WO2017123506A1

WO2017123506A1 - Orthopedic systems and methods

Info

Publication number: WO2017123506A1
Application number: PCT/US2017/012753
Authority: WO
Inventors: Kambiz BEHZADI; Alexandre Carvalho LEITE; Paul Kardel; Danny Kent WINKLER; Jesse Rusk; David Jacobs
Original assignee: Behzadi Kambiz
Priority date: 2016-01-11
Filing date: 2017-01-09
Publication date: 2017-07-20
Also published as: WO2017123506A9

Abstract

A system and method for allowing any surgeon, including those surgeons who perform a fewer number of a replacement procedure as compared to a more experienced surgeon who performs a greater number of procedures, to provide an improved likelihood of a favorable outcome approaching, if not exceeding, a likelihood of a favorable outcome as performed by a very experienced surgeon with the replacement procedure, such as by understanding the prosthesis installation environment (e.g., cup/cavity interface) and to provide intelligent and interactive tools and methods to standardize the installation process, including systems and methods for improving assembly, preparation, and installation of a prosthesis, the tools optionally including a secondary motion that preferably includes an ultrasonic vibration.

Description

ORTHOPEDIC SYSTEMS AND METHODS

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] The application claims benefit from the following: a) US Patent Application No. 62/277,294 filed 11 January 2016, b) US Patent Application No. 15/202,434 filed 5 July 2016, c) US Patent Application No. 15/235,032 filed 11 August 2016, d) US Patent Application No. 15/235,053 filed 11 August 2016, e) US Patent Application No. 15/362,675 filed 28 November 2016, f) US Patent Application No. 15/396,785 filed 2 January 2017, g) US Patent Application No. 15/398,996 filed 5 January 2017, h) US Patent Application No. 62/353,024 filed 21 June 2016, i) 62/355,657 filed 28 June 2016, j) US Patent Application No. 15/234,782 filed 11 August 2016, and k) US Patent Application No. 15/284,091 filed 3 October 2016, all the contents of all these applications hereby expressly incorporated by reference thereto in their entireties for all purposes.

FIELD OF THE INVENTION

[0002] The present invention relates generally to installation of a prosthesis, and more specifically, but not exclusively, to improvements in prosthesis placement and positioning and the present invention relates generally to orthopedic surgical and processing systems and procedures employing a prosthetic implant for, and more specifically, but not exclusively, to joint replacement therapies such as total hip replacement including controlled installation and positioning of the prosthesis such as during replacement of a pelvic acetabulum with a prosthetic implant, and relates generally to installation of a prosthesis, and more specifically, but not exclusively, to improvements in prosthesis placement and positioning, and relates generally to force measurement systems such as may be used in these systems and methods..

BACKGROUND OF THE INVENTION

[0003] The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also be inventions. [0004] Total hip replacement refers to a surgical procedure where a hip joint is replaced using a prosthetic implant. There are several different techniques that may be used, but all include a step of inserting an acetabular component into the acetabulum and positioning it correctly in three dimensions (along an X, Y, and Z axis).

[0005] In total hip replacement (THR) procedures there are advantages to patient outcome when the procedure is performed by a surgeon specializing in these procedures. Patients of surgeons who do not perform as many procedures can have increased risks of complications, particularly of complications arising from incorrect placement and positioning of the acetabular component.

[0006] The incorrect placement and positioning may arise even when the surgeon understood and intended the acetabular component to be inserted and positioned correctly. This is true because in some techniques, the tools for actually installing the acetabular component are crude and provide an imprecise, unpredictable coarse positioning outcome.

[0007] It is known in some techniques to employ automated and/or computer-assisted navigation tools, for example, x-ray fluoroscopy or computer guidance systems. There are computer assisted surgery techniques that can help the surgeon in determining the correct orientation and placement of the acetabular component. However, current technology provides that at some point the surgeon is required to employ a hammer/mallet to physically strike a pin or alignment rod. The amount of force applied and the location of the application of the force are variables that have not been controlled by these navigation tools. Thus even when the acetabular component is properly positioned and oriented, when actually impacting the acetabular component into place the actual location and orientation can differ from the intended optimum location and orientation. In some cases the tools used can be used to determine that there is, in fact, some difference in the location and/or orientation. However, once again the surgeon must employ an impacting tool (e.g., the hammer/mallet) to strike the pin or alignment rod to attempt an adjustment. However the resulting location and orientation of the acetabular component after the adjustment may not be, in fact, the desired location and/or orientation. The more familiar that the surgeon is with the use and application of these adjustment tools can reduce the risk to a patient from a less preferred location or orientation. In some circumstances, quite large impacting forces are applied to the prosthesis by the mallet striking the rod; these forces make fine tuning difficult at best and there is risk of fracturing and/or shattering the acetabulum during these impacting steps. [0008] Earlier patents issued to the present applicant have described problems associated with prosthesis installation, for example acetabular cup placement in total hip replacement surgery. See US Patent Numbers 9,168,154 and 9,220,612, which are hereby expressly incorporated by reference thereto in their entireties for all purposes. Even though hip replacement surgery has been one of the most successful operations, it continues to be plagued with a problem of inconsistent acetabular cup placement. Cup mal-positioning is the single greatest cause of hip instability, a major factor in polyethylene wear, osteolysis, impingement, component loosening and the need for hip revision surgery.

[0009] These incorporated patents explain that the process of cup implantation with a mallet is highly unreliable and a significant cause of this inconsistency. The patents note two specific problems associated with the use of the mallet. First is the fact that the surgeon is unable to consistently hit on the center point of the impaction plate, which causes undesirable torques and moment arms, leading to mal-alignment of the cup. Second, is the fact that the amount of force utilized in this process is non-standardized.

[0010] Traditionally these methods do not have any clear understanding of the forces, including magnitude and direction, involved in installing a prosthesis. A surgeon often relies on qualitative factors from tactile and auditory senses. Consequently, the surgeon is left somewhat haphazardly and variably relying on two different fixation methods (e.g., pins and press-fit) without knowing how or why.

[0011] In these patents there is presented a new apparatus and method of cup insertion which uses an oscillatory motion to insert the prosthesis. Prototypes have been developed and continue to be refined, and illustrate that vibratory force may allow insertion of the prosthesis with less force, as well, in some embodiments, of allowing simultaneous positioning and alignment of the implant.

[0012] There are other ways of breaking down of the large undesirable, torque-producing forces associated with the discrete blows of the mallet into a series of smaller, axially aligned controlled taps, which may achieve the same result incrementally, and in a stepwise fashion to those set forth in the incorporated patents, (with regard to, for example, cup insertion without unintended divergence).

[0013] There are two problems that may be considered independently, though some solutions may address both in a single solution. These problems include i) undesirable and unpredictable torques and moment arms that are related to the primitive method currently used by surgeons, which involves manually banging the mallet on an impaction plate mated to the prosthesis and ii) non- standardized and essentially uncontrolled and unquantized amounts of force utilized in these processes. These unpredictable torqueing forces may also be present in assembly of modular prosthetic systems, especially those that employ a mallet to strike one component onto another component during assembly.

[0014] Total hip replacement has been one of the most successful orthopedic operations. However, as has been previously described in the incorporated applications, it continues to be plagued with the problem of inconsistent acetabular cup placement. Cup mal-positioning is a significant cause of hip instability, a major factor in polyethylene wear, osteolysis, impingement, component loosening, and the need for hip revision surgery.

[0015] Solutions in the incorporated applications generally relate to particular solutions that may not, in every situation and implementation, achieve desired goal(s) of a surgeon. There are various sensing systems that may be used over a course of preparation and installation of a prosthesis, for example an acetabular cup. These sensing systems may detect various parameters such as an orientation angle of the prosthesis at any given time. These sensing systems may provide a set of periodic snapshots in time over the course of the procedure, but they do not provide true realtime continuous data over the installation procedure. That is, a surgeon may employ a sensing system to measure an orientation before striking an acetabular cup using a mallet and tamp, and may employ a sensing system to measure an orientation after striking the acetabular cup. But these sensing systems do not provide an orientation measurement (and in most cases no measurement of any information) during the strike. That is, the surgeon often measures, strikes, remeasures, restrikes, and repeats until the surgeon decides to stop. For a conventional system in which the surgeon manually swings the mallet and the installation model includes a sequence of discrete impulses from the mallet, this paradigm is understandable.

[0016] Some conventional systems may describe some measurements as "real time" but those systems are real time in the sense that the measurements are taken in the operating room during a procedure. The actual system does not provide realtime measurement during the actual insertion event. [0017] In the incorporated applications, alternatives to the manual swinging of the mallet are described and in these systems the conventional measurement paradigm may be unnecessarily restrictive.

[0018] What is needed is a system and method for allowing any surgeon, including those surgeons who perform a fewer number of a replacement procedure as compared to a more experienced surgeon who performs a greater number of procedures, to provide an improved likelihood of a favorable outcome approaching, if not exceeding, a likelihood of a favorable outcome as performed by a very experienced surgeon with the replacement procedure, such as by

understanding the prosthesis installation environment (e.g., cup/cavity interface) and to provide intelligent and interactive tools and methods to standardize the installation process, including systems and methods for improving assembly, preparation, and installation of a prosthesis.

BRIEF SUMMARY OF THE INVENTION

[0019] Disclosed is a system and method for improving assembly, preparation, and installation of a prosthesis. The following summary of the invention is provided to facilitate an understanding of some of the technical features related to prosthesis assembly and installation, and is not intended to be a full description of the present invention. A full appreciation of the various aspects of the invention can be gained by taking the entire specification, claims, drawings, and abstract as a whole. The present invention is applicable to other prosthesis in addition to acetabular cups, other modular prosthesis in addition to assembly of modular femoral and humeral prosthesis, and to other alignment and navigation systems in addition to referenced light guides.

[0020] Disclosed is a system and method for allowing any surgeon, including those surgeons who perform a fewer number of a replacement procedure as compared to a more experienced surgeon who performs a greater number of procedures, to provide an improved likelihood of a favorable outcome approaching, if not exceeding, a likelihood of a favorable outcome as performed by a very experienced surgeon with the replacement procedure, such as by understanding the prosthesis installation environment (e.g., cup/cavity interface) and to provide intelligent and interactive tools and methods to standardize the installation process.

[0021] The following summary of the invention is provided to facilitate an understanding of some of technical features related to total hip replacement, and is not intended to be a full description of the present invention. A full appreciation of the various aspects of the invention can be gained by taking the entire specification, claims, drawings, and abstract as a whole. The present invention is applicable to other surgical procedures, including replacement of other joints replaced by a prosthetic implant in addition to replacement of an acetabulum (hip socket) with an acetabular component (e.g., a cup). Use of pneumatic and electric motor implementations have both achieved a proof of concept development.

[0022] Some of the disclosed concepts involve creation of a system/method/tool/gun that vibrates an attached prosthesis, e.g., an acetabular cup. The gun may be held in a surgeon's hands and deployed. It may use a vibratory energy to insert (not impact) and position the cup into desired alignment (using current intra-operation measurement systems, navigation, fluoroscopy, and the like).

[0023] In one embodiment, a first gun-like device may be used for accurate impaction of the acetabular component at the desired location and orientation.

[0024] In another embodiment, a second gun-like device may be used for fine-tuning of the orientation of the acetabular component, such as one installed by the first gun-like device, by traditional mallet and tamp, or by other methodology. However the second gun-like device may be used independently of the first gun-like device for adjusting an acetabular component installed using an alternate technique. Similarly the second gun-like device may be used independently of the first gun-like device, particularly when the initial installation is sufficiently close to the desired location and orientation. These embodiments are not necessarily limited to fine-tuning as certain

embodiments permit complete re-orientation. Some implementations allow for removal of an installed prosthesis.

[0025] Another embodiment may include a third gun-like device that combines the functions of the first gun-like device and the second gun-like device. This embodiment enables the surgeon to accurately locate, insert, orient, and otherwise position the acetabular component with the single tool.

[0026] Another embodiment includes a fourth device that installs the acetabular component without use of the mallet and the rod, or use of alternatives to strike the acetabular component for impacting it into the acetabulum. This embodiment imparts a vibratory motion to an installation rod coupled to the acetabular component that enables low-force, impactless installation and/or positioning. [0027] An embodiment of the present invention may include axial alignment of force transference, such as, for example, an axially sliding hammer moving between stops to impart a non- torqueing installation force. There are various ways of motivating and controlling the sliding hammer, including a magnitude of transferred force. Optional enhancements may include pressure and/or sound sensors for gauging when a desired depth of implantation has occurred.

[0028] Other embodiments include adaptation of various devices for accurate assembly of modular prostheses, such as those that include a head accurately impacted onto a trunnion taper that is part of a stem or other element of the prosthesis.

[0029] Still other embodiments include an alignment system to improve site preparation, such as, for example, including a projected visual reference of a desired orientation of a tool and then having that reference marked and available for use during operation of the tool to ensure that the alignment remains proper throughout its use, such as during a reaming operation.

[0030] Further embodiments include enhancement of various tools, such as those used for cutting, trimming, drilling, and the like, with ultrasonic enhancement to make the device a better cutting, trimming, drilling, etc. device to enable its use with less strength and with improved accuracy.

[0031] Embodiments disclosed herein may include selective operational directionality or dynamic selective of different directionality modes (unidirection_01, unidirection_02, and/or bidirectional). That is, for a BMD that includes vibration, it may be advantageous to control whether that vibration is driven unidirectionally and/or bidirectionally. For example, for an installation tool that installs a prosthesis into bone, it may be advantageous when a net vibratory motion is driven towards the installation site (moves toward installation) and not driven away from the installation (moves toward extraction). In a revision tool, such as disclosed in US Patent Application No., 15/092,384, which is hereby expressly incorporated by reference in its entirety for all purposes, where it may be desired to remove a previously installed prosthesis, reversing the drive direction of the unidirectional operation helps to remove the prosthesis by providing net extractive forces on the prosthesis to be removed. As further described herein, in some implementations, it may be desirable to drive a tool operated by the BMD with a bidirectional motion. Such a system may be used with a new acetabular broach, particularly with bidirectional vibratory motion. [0032] An embodiment of the present invention may include a grip structure on a body of modular assembly that may provide an anchor for defining an alignment axis for a trunnion of the body and a head to be installed onto the trunnion.

[0033] An embodiment of the present invention may include a head grasper that secures the head into an optimized assembly position relative to the alignment axis/trunnion. The optimized assembly position may include non-relative canting and alignment with the alignment axis.

[0034] An embodiment of the present invention may include a holder that engages a grip structure and is coupled to a head grasper. The holder may aid in reducing waste of energy used in assembly of the head onto the trunnion and it may aid in the optimized positioning of the head relative to the alignment axis/trunnion before and/or during installation of the head onto the trunnion.

[0035] An embodiment of the present invention may include use of force source coupled to a head grasper/tool to generate assembly forces to install the head onto the trunnion. The force source may deliver one or more of a dynamic assembly force, a vibratory assembly force, a set of discrete assembly impacts, other assembly forces, and combinations thereof. The assembly force(s) may be applied the head grasper/tool to install the head onto the trunnion. The assembly force(s) may be constrained to operate along the alignment axis, and may be reduced by securing/anchoring the body of the modular prosthesis, such as by using a grip structure.

[0036] An embodiment of the present invention may include use of a force sensing mechanism coupled to a head grasper/tool to measure, possibly in true realtime (e.g., during dynamic operation of the tool to apply the assembly force(s)), the assembly force(s).

[0037] An embodiment of the present invention may include development and production of standards, guidelines, recommendations for an optimum force, or force range for the assembly force(s) to achieve a desired cold weld.

[0038] A modular prosthesis body, including a stem portion; a trunnion portion coupled to the stem portion, the trunnion portion having an insertion profile defining an insertion axis; and a grip structure coupled to the trunnion portion and disposed on the insertion axis.

[0039] A system for assembly of a modular prosthesis including a stem portion, a trunnion portion coupled to the stem portion, the trunnion portion having an insertion profile defining an insertion axis, and a prosthesis head configured to be installed on the trunnion portion and defining an installation aperture complementary to the insertion profile with the installation aperture defining an installation axis, including a head grasper including a housing defining a cavity complementary to an outer portion of the prosthesis head with the housing having a grasper axis extending through the cavity wherein the housing is configured to secure the prosthesis head within the cavity and align the grasper axis with the installation axis.

[0040] A method, including a) installing a set of prosthetic heads onto a set of associated trunnions to produce a set of cold welds using a range of measured assembly forces; and b) establishing, responsive to the range of measured assembly forces, a set of ranges of optimized assembly forces to predict production of a cold weld for a particular one prosthetic head installed onto a particular associated trunnion.

[0041] A modular prosthesis body, including a support portion, a trunnion portion coupled to the support portion, the trunnion portion having an insertion profile defining an insertion axis; and a grip structure coupled to the support portion and disposed in a first predetermined relationship to the insertion axis.

[0042] A modular prosthesis head having a body defining a trunnion cavity, the trunnion cavity having a trunnion installation axis, including an indicia disposed on an outer surface of the body, the indicia having a predetermined relationship with the trunnion installation axis.

[0043] A modular prosthesis trunnion component having a body defining a trunnion portion coupled to a trunnion extension, the trunnion extension having a trunnion extension installation axis, including an indicia disposed on an outer surface of the body, the indicia having a predetermined relationship with the trunnion extension installation axis.

[0044] An anvil for a modular prosthesis head, the head defining a trunnion installation axis and an outer spherical perimeter surface, including a body defining a top planar surface, a bottom planar surface spaced apart from and parallel to the top planar surface, an anvil axis extending through and perpendicular to the planar surfaces and a depression defined in the top surface with the depression complementary to the outer spherical perimeter surface and symmetric about the anvil axis; and an anvil axis interaction structure defined in the bottom surface with the anvil axis interaction structure symmetric about the anvil axis. [0045] An adapter for a modular prosthesis head, the head defining a trunnion installation axis, an outer spherical perimeter surface, and a planar face symmetric about the trunnion installation axis, including an anvil body defining a top planar surface, a bottom planar surface spaced apart from and parallel to the top planar surface, a circumferential channel in an outer surface of the anvil body disposed between and parallel to the planar surfaces, an anvil axis extending through and perpendicular to the planar surfaces and a depression defined in the top surface with the depression complementary to the outer spherical perimeter surface and symmetric about the anvil axis; an anvil axis interaction structure defined in the bottom surface with the anvil axis interaction structure symmetric about the anvil axis; and a shell defining a shell planar portion, a sidewall having an interior circumferential ledge complementary to the circumferential channel with the circumferential ledge spaced apart from and parallel to the shell planar portion and the sidewall further defining a shell cavity; wherein the shell further defines a shell alignment axis when the modular prosthetic head is installed in the depression and both the modular prosthetic head and anvil are installed in the shell cavity with the shell alignment axis aligned with the trunnion installation axis and with the anvil axis.

[0046] An apparatus for coupling an installation force from a force applicator to a modular prosthetic body when installing a modular prosthetic component to the modular prosthetic body, the modular prosthetic body defining a grip structure, including a rigid clamp body including a grip structure engagement element configured to secure the clamp body to the modular prosthetic body, the clamp body further including a force applicator engagement element configured to secure the clamp body to the force applicator wherein the installation force is coupled from the force applicator without a flexing of the rigid clamp body by more than 10 microns.

[0047] An apparatus for a coupling of an installation force from a force applicator to a modular prosthetic body when installing a modular prosthetic component to the modular prosthetic body, the modular prosthetic body defining a grip structure, including a trunnion portion defined on the modular prosthetic body having a trunnion insertion axis; a cavity portion defined in the modular prosthetic component having a trunnion engagement axis; a force application axis aligned with a direction of the installation force; and a clamp body including a grip structure engagement element configured to secure the clamp body to the modular prosthetic body, the clamp body further including a force applicator engagement element configured to secure the clamp body to the force applicator; wherein the clamp body maintains an alignment of all the axes during the coupling of the installation force. [0048] An adapter for a modular prosthesis component, the component defining an installation axis, an outer perimeter surface, and a component face symmetric about the installation axis, including an anvil body defining a top planar surface, a bottom planar surface spaced apart from and parallel to the top planar surface, a circumferential channel in an outer surface of the anvil body disposed between and parallel to the planar surfaces, an anvil axis extending through and perpendicular to the planar surfaces and a depression defined in the top surface with the depression complementary to the outer perimeter surface and symmetric about the anvil axis; an anvil axis interaction structure defined in the bottom surface with the anvil axis interaction structure symmetric about the anvil axis; and a shell defining a shell planar portion, a sidewall having an interior circumferential ledge complementary to the circumferential channel with the circumferential ledge spaced apart from and parallel to the shell planar portion and the sidewall further defining a shell cavity; wherein the shell further defines a shell alignment axis when the modular prosthetic component is installed in the depression and both the modular prosthetic component and anvil are installed in the shell cavity with the shell alignment axis aligned with the installation axis and with the anvil axis.

[0049] An apparatus for coupling an installation force from a force applicator to a modular prosthetic body when installing a modular prosthetic component to the modular prosthetic body, the modular prosthetic body defining a grip structure, including a clamp body including a grip structure engagement element configured to secure the clamp body to the modular prosthetic body, the clamp body further including a force applicator engagement element configured to secure the clamp body to the force applicator; and a force measurement apparatus, coupled to the clamp body, configured to quantify the installation force.

[0050] A method for producing a modular prosthesis component, including producing a modular prosthetic body including a modular assembly portion having an assembly axis; and defining a grip structure in the modular prosthetic body, the grip structure having a predetermined relationship to the assembly axis.

[0051] A method of marking an assembly axis for a modular prosthetic head having a trunnion cavity defining the assembly axis, including establishing the assembly axis; determining an intersection of the assembly axis with an outer surface of the modular prosthetic head; and marking the intersection with a visible indicia. [0052] A method for installing a modular prosthetic component having a first axis into an anvil having a second axis, including disposing the modular prosthetic component into a depression of the anvil; and aligning axially the modular prosthetic component with the anvil by aligning the axes.

[0053] A method for joining a modular prosthetic component to a modular prosthetic body, including locking the modular prosthetic component to the modular prosthetic body while an assembly of the modular prosthetic component is aligned with an assembly axis of the modular prosthetic body; and thereafter applying, while the axes are locked in alignment, an assembly force to cold weld the modular prosthetic component to the modular prosthetic body wherein the assembly force is axially aligned with the axes.

[0054] A bone preparation tool, including a bone-processing implement configured to process an in-patient bone using a primary motion in a primary mode of freedom of motion; and a motive system, coupled to the cutting implement, configured to operate the cutting implement in the primary mode of freedom of motion and in a secondary mode of primary mode of freedom different from the primary mode of freedom wherein the secondary mode of freedom includes an ultrasonic vibratory motion.

[0055] A method for preparing an in-patient bone, including processing, using a bone- processing implement, the in-patient bone using a primary motion in a primary mode of freedom of motion for the a bone-processing implement; and concurrently operating the a bone-processing implement in a secondary motion including a secondary mode of freedom of motion; wherein the secondary mode of freedom is different than the primary mode of freedom of motion; and wherein the secondary motion includes an ultrasonic vibration motion.

[0056] Additional embodiments of the present invention may include a hybrid medical device that is capable of selectively using vibratory and/or axial-impacts at various phases of an installation as required, needed, and/or desired by the surgeon during a procedure. The single tool remains coupled to the prosthesis or prosthesis component as the surgeon operates the hybrid medical device in any of its phases, which include a pure vibratory mode, a pure axial mode, a blended vibratory mode, and an impactful mode. The axial impacts in this device may have sub- modes: a) unidirectional axial force-IN, b) unidirectional axial force-OUT, or c) bidirectional axial force. [0057] A positioning device for an acetabular cup disposed in a bone, the acetabular cup including an outer shell having a sidewall defining an inner cavity and an opening with the sidewall having a periphery around the opening and with the acetabular cup having a desired abduction angle relative to the bone and a desired anteversion angle relative to the bone, including a controller including a trigger and a selector; a support having a proximal end and a distal end opposite of the proximal end, the support further having a longitudinal axis extending from the proximal end to the distal end with the proximal end coupled to the controller, the support further having an adapter coupled to the distal end with the adapter configured to secure the acetabular cup; and a number N, the number N, an integer greater than or equal to 2, of longitudinal actuators coupled to the controller and disposed around the support generally parallel to the longitudinal axis, each the actuator including an associated impact head arranged to strike a portion of the periphery, each impact head providing an impact strike to a different portion of the periphery when the associated actuator is selected and triggered; wherein each the impact strike adjusts one of the angles relative to the bone.

[0058] An installation device for an acetabular cup disposed in a pelvic bone, the acetabular cup including an outer shell having a sidewall defining an inner cavity and an opening with the sidewall having a periphery around the opening and with the acetabular cup having a desired installation depth relative to the bone, a desired abduction angle relative to the bone, and a desired anteversion angle relative to the bone, including a controller including a trigger; a support having a proximal end and a distal end opposite of said proximal end, said support further having a longitudinal axis extending from said proximal end to said distal end with said proximal end coupled to said controller, said support further having an adapter coupled to said distal end with said adapter configured to secure the acetabular cup; and an oscillator coupled to said controller and to said support, said oscillator configured to control an oscillation frequency and an oscillation magnitude of said support with said oscillation frequency and said oscillation magnitude configured to install the acetabular cup at the installation depth with the desired abduction angle and the desired anteversion angle without use of an impact force applied to the acetabular cup.

[0059] An installation system for a prosthesis configured to be implanted into a portion of bone at a desired implantation depth, the prosthesis including an attachment system, including an oscillation engine including a controller coupled to a vibratory machine generating an original series of pulses having a generation pattern, said generation pattern defining a first duty cycle of said original series of pulses; and a pulse transfer assembly having a proximal end coupled to said oscillation engine and a distal end, spaced from said proximal end, coupled to the prosthesis with said pulse transfer assembly including a connector system at said proximal end, said connector system complementary to the attachment system and configured to secure and rigidly hold the prosthesis producing a secured prosthesis with said pulse transfer assembly communicating an installation series of pulses, responsive to said original series of pulses, to said secured prosthesis producing an applied series of pulses responsive to said installation series of pulses; wherein said applied series of pulses are configured to impart a vibratory motion to said secured prosthesis enabling an installation of said secured prosthesis into the portion of bone to within 95% of the desired implantation depth without a manual impact.

[0060] A method for installing an acetabular cup into a prepared socket in a pelvic bone, the acetabular cup including an outer shell having a sidewall defining an inner cavity and an opening with the sidewall having a periphery around the opening and with the acetabular cup having a desired installation depth relative to the bone, a desired abduction angle relative to the bone, and a desired anteversion angle relative to the bone, including (a) generating an original series of pulses from an oscillation engine; (b) communicating said original series of pulses to the acetabular cup producing a communicated series of pulses at said acetabular cup; (c) vibrating, responsive to said communicated series of pulses, the acetabular cup to produce a vibrating acetabular cup having a predetermined vibration pattern; and (d) inserting the vibrating acetabular cup into the prepared socket within a first predefined threshold of the installation depth with the desired abduction angle and the desired anteversion angle without use of an impact force applied to the acetabular cup.

[0061] This method may further include (e) orienting the vibrating acetabular cup within the prepared socket within a second predetermined threshold of the desired abduction angle and within third predetermined threshold of the desired anteversion angle.

[0062] A method for inserting a prosthesis into a prepared location in a bone of a patient at a desired insertion depth wherein non-vibratory insertion forces for inserting the prosthesis to the desired insertion depth are in a first range, the method including (a) vibrating the prosthesis using a tool to produce a vibrating prosthesis having a predetermined vibration pattern; and (b) inserting the vibrating prosthesis into the prepared location to within a first predetermined threshold of the desired insertion depth using vibratory insertion forces in a second range, said second range including a set of values less than a lowest value of the first range. [0063] An embodiment may include a force sensing system within the BMD tools with capacity to measure the force experienced by the system(mlF) (Within the tool) and calculate the change in mIF with respect to time, number of impacts, or depth of insertion. This system provides a feedback mechanism through the BMD tools, for the surgeon, as to when impaction should stop, and or if it should continue. This feedback mechanism can be created by measuring and calculating force, acceleration or insertion depth. In some implementations, an applied force is measured (TmlF) and compared against the mIF in any of several possible ways and an evaluation is made as to whether the prosthesis has stopped moving responsive to the applied forces. There are different implications depending upon where in the installation process the system is operating. In other implementations, the applied force is known or estimated and then the mIF may need to be measured.

[0064] An aspect of the present invention is use of a special version of this system to map out ranges of parameters for different prosthesis/cavity interactions to allow better understanding of typical or applicable curve for a particular patient with a particular implant procedure.

[0065] A force sensing system for a medical device tools with capacity to measure the force experienced by the system(mlF) - (Within the tool) and calculate a change in mIF with respect to time, number of impacts, or depth of insertion, wherein this system provides a feedback mechanism through the device, for the surgeon, as to when impaction should stop, and/or whether it should continue while assessing a risk of too early suspension with poor seating or too late when bone fracture risk is high and wherein this feedback mechanism can be created by measuring and calculating force, acceleration or insertion depth, among other variables.

[0066] An embodiment of the present invention may include true realtime sensing before, during, and after a procedure. These procedures may benefit from this invasive sensing (sensing during preparation of bone, during installation of a prosthesis, and during assembly of a modular prosthesis) and not just periodic static snapshots. The invasive sensing may employ force sensing directly, or may employ acceleration, vibration, or acoustic sensing in addition to, or in lieu of, force sensing.

[0067] An apparatus, including a medical device operating over a continuous period including an initial act with the medical device to a subsequent act with the medical device; and a microelectromechanical (MEM) sensing system physically coupled to the medical device configured to provide a realtime parametric evaluation over the period. [0068] Any of the embodiments described herein may be used alone or together with one another in any combination. Inventions encompassed within this specification may also include embodiments that are only partially mentioned or alluded to or are not mentioned or alluded to at all in this brief summary or in the abstract. Although various embodiments of the invention may have been motivated by various deficiencies with the prior art, which may be discussed or alluded to in one or more places in the specification, the embodiments of the invention do not necessarily address any of these deficiencies. In other words, different embodiments of the invention may address different deficiencies that may be discussed in the specification. Some embodiments may only partially address some deficiencies or just one deficiency that may be discussed in the specification, and some embodiments may not address any of these deficiencies.

[0069] Other features, benefits, and advantages of the present invention will be apparent upon a review of the present disclosure, including the specification, drawings, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0070] The accompanying figures, in which like reference numerals refer to identical or functionally-similar elements throughout the separate views and which are incorporated in and form a part of the specification, further illustrate the present invention and, together with the detailed description of the invention, serve to explain the principles of the present invention.

[0071] FIG. 1-FIG. 6 illustrate embodiments including installation of a prosthesis, including installation into living bone;

[0072] FIG. 1 illustrates an embodiment of the present invention for a sliding impact device;

[0073] FIG. 2 illustrates a lengthwise cross-section of the embodiment illustrated in FIG. 1 including an attachment of a navigation device;

[0074] FIG. 3 illustrates a cockup mechanical gun embodiment, an alternative embodiment to the sliding impact device illustrated in FIG. 1 and FIG. 2;

[0075] FIG. 4 illustrates an alternative embodiment to the devices of FIG. 1-3 including a robotic structure; [0076] FIG. 5 illustrates an alternative embodiment to the devices of FIG. 1-4 including a pressure sensor to provide feedback;

[0077] FIG. 6 illustrates an alternative embodiment to the feedback system of FIG. 5 including a sound sensor to provide feedback for the embodiments of FIG. 1-5;

[0078] FIG. 7-FIG. 10 illustrate prosthesis assembly embodiments including use of variations of the prosthesis installation embodiments of FIG. 1-FIG. 6, such as may be used to reduce a risk of trunnionosis;

[0079] FIG. 7 illustrates a modular prosthesis and assembly tools;

[0080] FIG. 8 illustrates a femoral head to be assembled onto a trunnion attached to a femoral stem;

[0081] FIG. 9 illustrates alignment of an installation device with the femoral head for properly aligned impaction onto the trunnion, such as an embodiment of FIG. 1-FIG. 6 adapted for this application;

[0082] FIG. 10 illustrates use of a modified vibratory system for assembly of the modular prosthesis;

[0083] FIG. 11-FIG. 12 illustrate an improvement to site preparation for an installation of a prosthesis;

[0084] FIG. 11 illustrates an environment in which a prosthesis is installed highlighting problem with site preparation; and

[0085] FIG. 12 illustrates an alignment system for preparation and installation of a prosthesis;

[0086] FIG. 13 illustrates modified surgical devices incorporating vibratory energy as at least an aid to mechanical preparation;

[0087] FIG. 14-FIG. 16 relate to a first particular implementation of a mechanical BMD for controlled axial impact;

[0088] FIG. 14 illustrates a perspective view of the particular BMD; [0089] FIG. 15 illustrates a first actuator for use with the particular BMD of FIG. 14; and

[0090] FIG. 16 illustrates a second actuator for use with the particular BMD of FIG. 14;

[0091] FIG. 17 illustrates a cross-sectional view of an impact energy control mechanism (spring preload) as may be used in the particular BMD of FIG. 14;

[0092] FIG. 18 illustrates an internal view of an impact energy control mechanism (spring preload) as may be used in the particular BMD of FIG. 14;

[0093] FIG. 19 illustrates cross-sectional view of an impact energy control mechanism (friction) as may be used in the particular BMD of FIG. 14;

[0094] FIG. 20 illustrates an internal view of an impact energy control mechanism (friction) as may be used in the particular BMD of FIG. 14;

[0095] FIG. 21 illustrates a close-up detail of an impact energy control mechanism (friction), ball-detent as may be used in the particular BMD of FIG. 14;

[0096] FIG. 22 illustrates a bottom view of an impact energy control mechanism (friction) as may be used in the particular BMD of FIG. 14;

[0097] FIG. 23-FIG. 24 relate to a second particular implementation of a mechanical BMD for controlled axial impact;

[0098] FIG. 23 illustrates a hand-operated slide hammer implementation for the mechanical BMD; and

[0099] FIG. 24 illustrates an exploded view of the mechanical BMD of FIG. 23;

[0100] FIG. 25-FIG. 27 relate to a third particular implementation of a mechanical BMD for controlled axial impact;

[0101] FIG. 25 illustrates a pneumatically-operated slide hammer implementation for the mechanical BMD;

[0102] FIG. 26 illustrates an internal view of the mechanical BMD of FIG. 25;

[0103] FIG. 27 illustrates an exploded view of the mechanical BMD of FIG. 25; [0104] FIG. 28 illustrates a detail view of the pneumatic engine for the BMD of FIG. 25;

[0105] FIG. 29 illustrates a BMD having bidirectional longitudinal motion;

[0106] FIG. 30 illustrates a BMD having bidirectional rotational motion;

[0107] FIG. 31 illustrates a first embodiment for a BMD5 tool;

[0108] FIG. 32 illustrates a second embodiment for a BMD5 tool;

[0109] FIG. 33 illustrates a third embodiment for a BMD5 tool;

[0110] FIG. 34 through FIG. FIG. 50 illustrate a particular implementation of a mechanical alignment system for use with an embodiment of a BMD5 tool;

[0111] FIG. 34 illustrates a side view of a prosthetic body to be mechanically joined to an installable prosthetic head;

[0112] FIG. 35 and FIG. 36 illustrate a set of views of a prosthetic head to be installed on the prosthetic body of FIG. 34;

[0113] FIG 35 illustrates a top view of the prosthetic head;

[0114] FIG. 36 illustrates a side view of the prosthetic head;

[0115] FIG. 37 through FIG. 40 illustrate a set of views for an anvil for imparting an assembly force to the prosthetic head;

[0116] FIG. 37 illustrates a side view of the anvil;

[0117] FIG. 38 illustrates a top view of the anvil;

[0118] FIG. 39 illustrates a bottom view of the anvil; and

[0119] FIG. 40 illustrates a sectional view through the anvil;

[0120] FIG. 41 through FIG. 45 illustrate a set of views of a two-part clamp for securing the anvil to the prosthetic head;

[0121] FIG. 41 illustrates a side view of the two-part clamp; [0122] FIG. 42 illustrates a top view of the two-part clamp;

[0123] FIG. 43 illustrates a bottom view of the two-part clamp;

[0124] FIG. 44 illustrates a sectional view through the two-part clamp; and

[0125] FIG. 45 illustrates an enlarged view of FIG. 27;

[0126] FIG. 46 through FIG. 48 illustrate a set of views of a clamp for attachment to the prosthetic body and apply an aligned assembly force to the prosthetic head by use of the two-part clamp;

[0127] FIG. 46 illustrates a top view of the clamp; [0128] FIG. 47 illustrates an end view of the clamp; and [0129] FIG. 48 illustrates a side view of the clamp;

[0130] FIG. 49 illustrates a stackup view for the mechanical alignment system shown securing, aligning, and applying an assembly force to the prosthetic head to install it onto the prosthetic body;

[0131] FIG. 50 illustrates a representative manual torque wrench which may be used with the system illustrated in FIG. 49 to apply a predetermined assembly force to produce a desired mechanical join of the prosthetic head onto the prosthetic body;

[0132] FIG. 51 illustrates a side view of an alternative prosthetic body to be mechanically joined to an installable prosthetic head;

[0133] FIG. 52 - FIG. 55 illustrate a set of standard orthopedic bone preparation tools;

[0134] FIG. 52 illustrates a perspective view of a powered bone saw;

[0135] FIG. 53 illustrates a broach attachment for a powered reciprocating bone preparation tool;

[0136] FIG. 54 illustrates a hand-operated reamer; and

[0137] FIG. 55 illustrates a set of bone preparation burrs; [0138] FIG. 56 illustrates a side view of a first set of components for a conventional bone preparation process;

[0139] FIG. 57 illustrates a side view of a second set of components for a three-dimensional bone sculpting process that may be enabled by some embodiments of the present invention;

[0140] FIG. 58 illustrates a plan diagram of a smart tool robot;

[0141] FIG. 59 illustrates a set of "cup prints" for a number of interactions between a cup and a cavity;

[0142] FIG. 60 illustrates a particular one representative cup print;

[0143] FIG. 61 illustrates a controlled modulated installation force envelope;

[0144] FIG. 62 illustrates an example installation force envelope that is representative of use of a mallet in its production;

[0145] FIG. 63 illustrates an example installation force envelope that is representative of use of a BMD3 in its production;

[0146] FIG. 64 illustrates an example installation force envelope that is representative of use of a BMD4 in its production;

[0147] FIG. 65-FIG. 68 relate to a vibratory Behzadi Medical Device (BMD3);

[0148] FIG. 65 illustrates a representative installation system;

[0149] FIG. 66 illustrates a disassembly of the representative installation system of FIG. 7;

[0150] FIG. 67 illustrates a first disassembly view of the pulse transfer assembly of the installation system of FIG. 65;

[0151] FIG 68 illustrates a second disassembly view of the pulse transfer assembly of the installation system of FIG. 65;

[0152] FIG. 69 illustrates a Force Resistance (FR) curve; [0153] FIG. 70-FIG. 71 illustrate a general force measurement system for understanding an installation of a prosthesis into an installation site (e.g., an acetabular cup into an acetabulum during total hip replacement procedures);

[0154] FIG. 70 illustrates an initial engagement of a prosthesis to a cavity when the prosthesis is secured to a force sensing tool;

[0155] FIG. 71 illustrates a partial installation of the prosthesis of FIG. 70 into the cavity by operation of the force sensing tool;

[0156] FIG. 72 illustrates a generalized FR curve illustrating various applicable forces implicated in operation of the tool in FIG. 70 and FIG. 71;

[0157] FIG. 73-FIG. 78 illustrate a first specific implementation of the system and method of FIG. 70-FIG. 72;

[0158] FIG. 73 illustrates a representative plot of insertion force for a cup during installation;

[0159] FIG. 74 illustrates a first particular embodiment of a BMDX force sensing tool;

[0160] FIG. 75 illustrates a graph including results of a drop test over time;

[0161] FIG. 76 illustrates a graph of measured impact force as impact energy is increased;

[0162] FIG. 77 illustrates a discrete impact control and measurement process; and

[0163] FIG. 78 illustrates a warning process;

[0164] FIG. 79-FIG. 84 illustrate a second specific implementation of the system and method of FIG. 70-FIG. 72;

[0165] FIG. 79 illustrates a basic force sensor system for controlled insertion;

[0166] FIG. 80 illustrates an FR curve including TmlF and mIF as functions of displacement;

[0167] FIG. 81 illustrates a generic force sensor tool to access variables of interest in FIG.

80;

[0168] FIG 82 illustrates a B-cloud tracking process using TmlF and MIF measurements; [0169] FIG. 83 illustrates a control system for the "controlled action" referenced in FIG. 82; and

[0170] FIG. 84 illustrates possible B-cloud regulation strategies;

[0171] FIG. 85 illustrates a generalized BMD including realtime invasive sense

measurement.

DETAILED DESCRIPTION OF THE INVENTION

[0172] Embodiments of the present invention provide a system and method for improving assembly, preparation, and installation of a prosthesis. The following description is presented to enable one of ordinary skill in the art to make and use the invention and is provided in the context of a patent application and its requirements.

[0173] Embodiments of the present invention provide a system and method for allowing any surgeon, including those surgeons who perform a fewer number of a replacement procedure as compared to a more experienced surgeon who performs a greater number of procedures, to provide an improved likelihood of a favorable outcome approaching, if not exceeding, a likelihood of a favorable outcome as performed by a very experienced surgeon with the replacement procedure, such as by understanding the prosthesis installation environment (e.g., cup/cavity interface) and to provide intelligent and interactive tools and methods to standardize the installation process. The following description is presented to enable one of ordinary skill in the art to make and use the invention and is provided in the context of a patent application and its requirements.

[0174] Various modifications to the preferred embodiment and the generic principles and features described herein will be readily apparent to those skilled in the art. Thus, the present invention is not intended to be limited to the embodiment shown but is to be accorded the widest scope consistent with the principles and features described herein.

[0175] Definitions

[0176] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this general inventive concept belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0177] The following definitions apply to some of the aspects described with respect to some embodiments of the invention. These definitions may likewise be expanded upon herein.

[0178] As used herein, the term "or" includes "and/or" and the term "and/or" includes any and all combinations of one or more of the associated listed items. Expressions such as "at least one of," when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.

[0179] As used herein, the singular terms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to an object can include multiple objects unless the context clearly dictates otherwise.

[0180] Also, as used in the description herein and throughout the claims that follow, the meaning of "in" includes "in" and "on" unless the context clearly dictates otherwise. It will be understood that when an element is referred to as being "on" another element, it can be directly on the other element or intervening elements may be present therebetween. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present.

[0181] As used herein, the term "set" refers to a collection of one or more objects. Thus, for example, a set of objects can include a single object or multiple objects. Objects of a set also can be referred to as members of the set. Objects of a set can be the same or different. In some instances, objects of a set can share one or more common properties.

[0182] As used herein, the term "adjacent" refers to being near or adjoining. Adjacent objects can be spaced apart from one another or can be in actual or direct contact with one another. In some instances, adjacent objects can be coupled to one another or can be formed integrally with one another.

[0183] As used herein, the terms "connect," "connected," and "connecting" refer to a direct attachment or link. Connected objects have no or no substantial intermediary object or set of objects, as the context indicates. [0184] As used herein, the terms "couple," "coupled," and "coupling" refer to an operational connection or linking. Coupled objects can be directly connected to one another or can be indirectly connected to one another, such as via an intermediary set of objects.

[0185] The use of the term "about" applies to all numeric values, whether or not explicitly indicated. This term generally refers to a range of numbers that one of ordinary skill in the art would consider as a reasonable amount of deviation to the recited numeric values (i.e., having the equivalent function or result). For example, this term can be construed as including a deviation of +10 percent of the given numeric value provided such a deviation does not alter the end function or result of the value. Therefore, a value of about 1% can be construed to be a range from 0.9% to 1.1%.

[0186] As used herein, the terms "substantially" and "substantial" refer to a considerable degree or extent. When used in conjunction with an event or circumstance, the terms can refer to instances in which the event or circumstance occurs precisely as well as instances in which the event or circumstance occurs to a close approximation, such as accounting for typical tolerance levels or variability of the embodiments described herein.

[0187] As used herein, the terms "optional" and "optionally" mean that the subsequently described event or circumstance may or may not occur and that the description includes instances where the event or circumstance occurs and instances in which it does not.

[0188] As used herein, the term "bone" means rigid connective tissue that constitute part of a vertebral skeleton, including mineralized osseous tissue, particularly in the context of a living patient undergoing a prosthesis implant into a portion of cortical bone. A living patient, and a surgeon for the patient, both have significant interests in reducing attendant risks of conventional implanting techniques including fracturing/shattering the bone and improper installation and positioning of the prosthesis within the framework of the patient's skeletal system and operation.

[0189] As used herein, the term "size" refers to a characteristic dimension of an object. Thus, for example, a size of an object that is spherical can refer to a diameter of the object. In the case of an object that is non- spherical, a size of the non-spherical object can refer to a diameter of a corresponding spherical object, where the corresponding spherical object exhibits or has a particular set of derivable or measurable properties that are substantially the same as those of the non-spherical object. Thus, for example, a size of a non-spherical object can refer to a diameter of a corresponding spherical object that exhibits light scattering or other properties that are substantially the same as those of the non-spherical object. Alternatively, or in conjunction, a size of a non-spherical object can refer to an average of various orthogonal dimensions of the object. Thus, for example, a size of an object that is a spheroidal can refer to an average of a major axis and a minor axis of the object. When referring to a set of objects as having a particular size, it is contemplated that the objects can have a distribution of sizes around the particular size. Thus, as used herein, a size of a set of objects can refer to a typical size of a distribution of sizes, such as an average size, a median size, or a peak size.

[0190] As used herein, mallet or hammer refers to an orthopedic device made of stainless steel or other dense material having a weight generally approximate that of a carpenter's hammer or a stonemason's lump hammer.

[0191] As used herein, an impact force for impacting an acetabular component (e.g., an acetabular cup prosthesis) includes forces from striking an impact rod multiple times with the orthopedic device that are generally similar to the forces that may be used to drive a three inch nail into a piece of lumber using the carpenter's hammer by striking the nail approximately a half-dozen times to completely seat the nail. Without limiting the preceding definition, a representative value in some instances includes a force of approximately 10 lbs./square inch.

[0192] As used herein, the term "realtime" sensing means sensing relevant parameters (e.g., force, acceleration, vibration, acoustic, and the like) during processing.

[0193] As used herein, the term "BMD" means Behzadi Medical Device, a range of orthopedic tools for preparation, installation, measurement, adjustment, and other processings of orthopedic systems, including prostheses and tissue. BMD may include one or more of a BMD2, BMD3, BMD4, BMD5, and/or BMD7 unless the context requires or excludes one or more of these systems. BMD2 a tool for correcting of a mal-positioned implant such as a cup, BMD3 a vibratory tool used for vibratory insertion/adjustment of an prosthesis into bone; BMD4 controlled impaction (the magnitude and direction is now controlled- unlike a mallet), BMD5 a tool created for application of prosthesis to prosthesis, to solve the problem of tribocorrosion, and trunnionosis, and/or BMD7 a Hybrid of multiple tools (e.g.,. a BMD3 and a BMD4), for example intended to initiate insertion with a BMD3 vibratory tool (insert and align) AND, then complete the insertion with a BMD4 controlled impaction tool with a mode switch of the same tool. [0194] The following description relates to improvements in a wide-range of prostheses installations into live bones of patients of surgeons. The following discussion focuses primarily on total hip replacement (THR) in which an acetabular cup prosthesis is installed into the pelvis of the patient. This cup is complementary to a ball and stem (i.e., a femoral prosthesis) installed into an end of a femur engaging the acetabulum undergoing repair.

[0195] Embodiments of the present invention may include one of more solutions to the above problems. The incorporated US Patent No. 9,168,154 includes a description of several embodiments, sometimes referred to herein as a BMD3 device, some of which illustrate a principle for breaking down large forces associated with the discrete blows of a mallet into a series of small taps, which in turn perform similarly in a stepwise fashion while being more efficient and safer. The BMD3 device produces the same displacement of the implant without the need for the large forces from the repeated impacts from the mallet. The BMD3 device may allow modulation of force required for cup insertion based on bone density, cup geometry, and surface roughness. Further, a use of the BMD3 device may result in the acetabulum experiencing less stress and deformation and the implant may experience a significantly smoother sinking pattern into the acetabulum during installation. Some embodiments of the BMD3 device may provide a superior approach to these problems, however, described herein are two problems that can be approached separately and with more basic methods as an alternative to, or in addition to, a BMD3 device. An issue of undesirable torques and moment arms is primarily related to the primitive method currently used by surgeons, which involves manually banging the mallet on the impaction plate. The amount of force utilized in this process is also non-standardized and somewhat out of control.

[0196] With respect to the impaction plate and undesirable torques, an embodiment of the present invention may include a simple mechanical solution as an alternative to some BMD3 devices, which can be utilized by the surgeon's hand or by a robotic machine and in some cases a smart tool robotic machine or a three-dimensional bone sculpting tool. A direction of the impact may be directed or focused by any number of standard techniques (e.g., A-frame, C-arm or navigation system). Elsewhere described herein is a refinement of this process by considering directionality in the reaming process, in contrast to only considering it just prior to impaction. First, an embodiment may eliminate the undesirable torques by delivering the impacts by a sledgehammer device or a (hollow cylindrical mass) that travels over a stainless rod. [0197] As noted in the background, the surgeon prepares the surface of the hipbone which includes attachment of the acetabular prosthesis to the pelvis. Conventionally, this attachment includes a manual implantation in which a mallet is used to strike a tamp that contacts some part of the acetabular prosthesis. Repeatedly striking the tamp drives the acetabular prosthesis into the acetabulum. Irrespective of whether current tools of computer navigation, fluoroscopy, robotics (and other intra-operative measuring tools) have been used, it is extremely unlikely that the acetabular prosthesis will be in the correct orientation once it has been seated to the proper depth by the series of hammer strikes. After manual implantation in this way, the surgeon then may apply a series of adjusting strikes around a perimeter of the acetabular prosthesis to attempt to adjust to the desired orientation. Currently such post-impaction result is accepted as many surgeons believe that post- impaction adjustment creates an unpredictable and unreliable change which does not therefore warrant any attempts for post-impaction adjustment.

[0198] In most cases, any and all surgeons including an inexperienced surgeon may not be able to achieve the desired orientation of the acetabular prosthesis in the pelvis by conventional solutions due to unpredictability of the orientation changes responsive to these adjusting strikes. As noted above, it is most common for any surgeon to avoid post-impaction adjustment as most surgeons understand that they do not have a reliable system or method for improving any particular orientation and could easily introduce more/greater error. The computer navigation systems, fluoroscopy, and other measuring tools are able to provide the surgeon with information about the current orientation of the prosthesis (in real time) during an operation and after the prosthesis has been installed and its deviation from the desired orientation, but the navigation systems (and others) do not protect against torsional forces created by the implanting/positioning strikes. The prosthesis will find its own position in the acetabulum based on the axial and torsional forces created by the blows of the mallet. Even those navigation systems used with robotic systems (e.g., MAKE) that attempt to secure an implant in the desired orientation prior to impaction are not guaranteed to result in the installation of the implant at the desired orientation because the actual implanting forces are applied by a surgeon swinging a mallet to manually strike the tamp.

[0199] A Behzadi Medical Device (BMD) is herein described and enabled that eliminates this crude method (i.e., mallet, tamp, and surgeon- applied mechanical implanting force) of the prosthesis (e.g., the acetabular cup). A surgeon using the BMD is able to insert the prosthesis exactly where desired with proper force, finesse, and accuracy. Depending upon implementation details, the installation includes insertion of the prosthesis into patient bone, within a desired threshold of metrics for insertion depth and location) and may also include, when appropriate and/or desired, positioning at a desired orientation with the desired threshold further including metrics for insertion orientation). The use of the BMD reduces risks of fracturing and/or shattering the bone receiving the prosthesis and allows for rapid, efficient, and accurate (atraumatic) installation of the prosthesis. The BMD provides a viable interface for computer navigation assistance (also useable with all intraoperative measuring tools including fluoroscopy) during the installation as a lighter more responsive touch may be used.

[0200] The BMD encompasses many different embodiments for installation and/or positioning of a prosthesis and may be adapted for a wide range of prostheses in addition to installation and/or positioning of an acetabular prosthesis during THR.

[0201] FIG. 1 illustrates an embodiment of the present invention for a sliding impact device 100, and FIG. 2 illustrates a lengthwise cross-section of sliding impact device 100 including an attachment of a navigation device 205.

[0202] Device 100 includes a moveable hammer 105 sliding axially and freely along a rod 110. Rod 110 includes a proximal stop 115 and distal stop 120. These stops that may be integrated into rod 110 to allow transference of force to rod 110 when hammer 105 strikes distal stop 120. At a distal end 210 of rod 110, device 100 includes an attachment system 215 for a prosthesis 220. For example, when prosthesis 220 includes an acetabular cup having a threaded cavity 225, attachment system 215 may include a complementary threaded structure that screws into threaded cavity 225. The illustrated design of device 100 allows only a perfect axial force to be imparted. The surgeon cannot deliver a blow to the edge of an impaction plate. Therefore the design of this instrument is in and of itself protective, eliminating a problem of "surgeon's mallet hitting on the edge of the impaction plate" or other mis-aligned force transference, and creating undesirable torques, and hence unintentional mal-alignment of prosthesis 220 from an intended position/orientation.

[0203] FIG. 3 illustrates a cockup mechanical gun 300 embodiment, an alternative embodiment to the sliding impact device illustrated in FIG. 1 and FIG. 2. An alternate embodiment includes cockup mechanical gun 300 that uses the potential energy of a cocked up spring 305 to create an axially aligned impaction force. Hammer 105 is drawn back and spring 305 is locked until an operator actuates a trigger 310 to release spring 305 and drive hammer 105 along rod 110 to strike distal stop 120 and transfer an axially aligned impacting force to prosthesis 220. [0204] Each pull of trigger 310 creates the same predetermined fixed unit of force (some alternatives may provide a variably predetermined force). The surgeon cannot deliver a misaligning impact to an impaction plate with this design.

[0205] FIG. 4 illustrates an alternative robotic device 400 embodiment to the devices of FIG. 1-3 including a robotic control structure 405. For example, device 100 and/or device 300 may be mounted with robot control structure 405 and the co-axial impacts may be delivered mechanically by a robotic tool using pneumatic or electric energy.

[0206] FIG. 5 illustrates an alternative embodiment 500 to the devices of FIG. 1-4 including a pressure sensor 505 to provide feedback during installation. With respect to management of the force required for some of these tasks, it is noted that with current techniques (the use of the mallet) the surgeon has no indication of how much force is being imparted onto the implant and/or the implant site (e.g., the pelvis). Laboratory tests may be done to estimate what range of force should be utilized in certain age groups (as a rough guide) and then fashioning a device 500, for example a modified sledgehammer 100 or cockup gun 300 to produce just the right amount of force. Typically the surgeon may use up to 2000N to 3000N of force to impact a cup into the acetabular cavity. Also, since some embodiments cannot deliver the force in an incremental fashion as described in association with the BMD3 device, device 500 includes a stopgap mechanism. Some embodiments of the BMD3 device have already described the application of a sensor in the body of the impaction rod. Device 500 includes sensing system/assembly 505 embedded in device 500, for example proximate rod 110 near distal end 210, and used to provide valuable feedback information to the surgeon. Pressure sensor 505 can let the surgeon know when the pressures seems to have

maximized, whether used for the insertion of an acetabular cup, or any other implant including knee and shoulder implants and rods used to fix tibia and femur fractures. When pressure sensor 505 is not showing an advance or increase in pressure readings and has plateaued, the surgeon may determine it is time to stop operation/impacting. An indicator, for example an alarm can go off or a red signal can show when maximal peak forces are repeatedly achieved. As noted above, the incorporated patents describe a presence of a pressure sensor in an installation device, the presence of which was designed as part of a system to characterize an installation pulse pattern communicated by a pulse transfer assembly. The disclosure here relates to a pressure sensor provided not to characterize the installation pulse pattern but to provide an in situ feedback mechanism to the surgeon as to a status of the installation, such as to reduce a risk of fracturing the installation site. Some embodiments may also employ this pressure sensor for multiple purposes including characterization of an applied pulse pattern such as, for example, when the device includes automated control of an impacting engine coupled to the hammer. Other embodiments of this invention may dispose the sensor or sensor reading system within a handle or housing of the device rather than in the central rod or shaft.

[0207] FIG. 6 illustrates an alternative device 600 embodiment to the feedback system of FIG. 5 including a sound sensor 605 to provide feedback for the embodiments of FIG. 1-5. Surgeons frequently use a change in pitch (sound) to gauge whether an implant (e.g., the cup) has "bottomed out" and device 600 includes sound sensor 605 either attached or coupled to rod 110 or otherwise disposed separately in the operating room. Sound sensor system/assembly 605 may be used in lieu of, or in addition to, pressure sensor system/assembly 505 illustrated in FIG. 5.

[0208] FIG. 7-FIG. 10 illustrate prosthesis assembly embodiments including use of variations of the prosthesis installation embodiments of FIG. 1-FIG. 6, such as may be used to reduce a risk of trunnionosis or for other advantage. FIG. 7 illustrates a modular prosthesis 700 and assembly tool 705. Prosthesis 700 includes a head 710 and a trunnion taper 715 at an end of a stem 720 (e.g., a femoral stem for supporting a ball head to fit within an acetabular cup used in a total hip replacement procedure). During the procedure, the surgeon assembles prosthesis 700 by using tool 705 which may include an impact rod 725 attached to a head coupler 730. The surgeon uses tool 705 to drive head 710 onto trunnion taper 715 which conventionally includes a free mallet striking tool 705. Such a procedure may be prone to the similar problems as installation of a prosthesis into an implant site, namely application of off-axis torqueing forces and an uncertainty of applied force and completion of assembly.

[0209] It is believed that even a 0.1 degree mal-alignment on head 710 on trunnion taper 715 may lead to progressive wear and metalosis. Variations of the embodiments of devices illustrated in FIG. 1-FIG. 6 and its associated content may be developed to help resolve this problem.

[0210] FIG. 8 illustrates a femoral head 805, a variation of head 710 illustrated in FIG. 7, to be assembled onto trunnion taper 715 that is coupled to femoral stem 720. A center dot 810 may be placed on femoral (or humeral) head 805 to be impacted using tool 705.

[0211] FIG. 9 illustrates alignment of an installation device 900, a variation of any of devices 100-600, with femoral head 805 for properly aligned impaction onto trunnion taper 715, such as an embodiment of FIG. 1-FIG. 6 adapted for this application. Such adaptation may include, for example, an axial channel 910 to view dot 810 through a slot 915, and align force transference, prior to operation of hammer 105. A sledgehammer 920 is coupled to a cock-up spring 925.

[0212] Dot 810 can be aligned with an impactor/device/gun. Once axial alignment, such as through the sight channel, has been confirmed, a sledgehammer, a cockup gun, or other similar device can bang the impactor onto femoral (humeral) head 805 to impact it on trunnion taper 715. The co-axiality of the head and the device can be confirmed visually (for example, through a hollow cylinder that comprises a center shaft of the device) or with a variety of electronic and laser methods.

[0213] FIG. 10 illustrates use of a modified vibratory system 1000, a variation of installation device 900 for assembly of the modular prosthesis illustrated in FIG. 7. Alternatively to device 900, a variation of the BMD3 device can be used to insert the femoral and humeral heads 710 onto trunnion taper 715. For example, a version of the BMD3 device where femoral head 710 is grasped by a "vibrating gun" and introduced methodically and incrementally onto trunnion taper 715. Since there are no large forces being applied to the head/trunnion junction, there is essentially no possibility, or a reduced possibility, of head 710 seating onto trunnion taper 715 in a misaligned fashion. It would be possible to use the same technique of marking the center of head 710 and lining it up with trunnion taper 715 and device axially before operating the device.

[0214] FIG. 11-FIG. 12 illustrate an improvement to site 1100 preparation for an installation of a prosthesis 1105. FIG. 11 illustrates an environment 1100 in which prosthesis 1105 is installed highlighting a problem with site preparation for a prosthesis installation procedure having variable density bone (line thickness/separation distance reflecting variable bone density) of acetabulum 1110.

[0215] There is a secondary problem with the process of acetabular preparation and implantation that leads to cup mal-alignment. Currently, during the process of acetabular reaming, surgeons make several assumptions. One common assumption is that the reamer is fully seated in a cavity and surrounded on all sides by bone. Another common assumption is that the bone that is being reamed is uniform in density. Imagine a carpenter that is preparing to cut a piece of wood with a saw. Now imagine that parts of this piece of wood are embedded with cement and some parts of the piece of wood are hollow and filled with air. The carpenter's saw will not produce a precise cut on this object. Some parts are easy to cut and some parts are harder to cut. The saw blades skives and bends in undesirable ways. A similar phenomenon happens in acetabular preparation with a reamer and when performing the cuts for knee replacement with a saw. With respect to the acetabulum, the side of the cavity that is incomplete (side of the reamer that is uncovered) will offer less resistance to the reamer and therefor the reamer preferentially reams towards the direction of the uncovering. Second, the reamer cuts the soft bone much more easily than the dense and sclerotic bone, so the reamer moves away from the sclerotic bone and moves toward the soft bone. From a machining perspective, the reaming and preparation of the acetabulum may not be concentric or precise. This maybe a significant factor in the surgeon's inability to impact the cup in the desired location

[0216] FIG. 12 illustrates an alignment system 1200 for preparation and installation of a prosthesis to help address/minimize this effect. A first step that can be taken is to include

directionality into the process of reaming at the outset, and not just at the last step during impaction. Current technique allows the surgeon to ream the cup haphazardly moving the reamer handle in all directions, being ignorantly unaware that he is actually creating a preference for the sinking path of the acetabular implant. Ultimately the direction in which the surgeon reams may in fact be determining the position/path of the final implant. The surgeon then impacts the cup using the traditional A-frame or any of the currently used intra-operative measurement techniques such as navigation or fluoroscopy. These methods provide information about the position of the cup either as it is being implanted or after the implantation has occurred. None of these techniques

predetermine the cup's path or function to guide the cup in the correct path.

[0217] Proposed is a method and a technique to eliminate/reduce this problem. Before the surgeon begins to ream the acetabulum, the reamer handle should be held, with an A-frame attached, in such a way to contemplate the final position of the reamer and hence the implant, (e.g., hold the reamer in 40 degree abduction and 20 degree anteversion reaming is started). This step could also be accomplished with navigation or fluoroscopy. The surgeon could, for example, immediately mark this position on a screen or the wall in the operating room as described below and as illustrated in FIG. 12. After the anticipated position of the reamer is marked, the surgeon can do whatever aspect of reaming that needs to be done. For example the first reaming usually requires medialization in which the reamer is directed quite vertically to ream in to the pulvinar. Typically three or four reamings are done. First, the acetabular cavity is medialized. The other reamings function to get to the subchondral bone in the periphery of the acetabulum. One solution may be that after each reaming, the reamer handle be held in the final anticipated position of the implant. In some cases it may be difficult to have an A-frame attached to every reamer and to estimate the same position of the reamer in the operating space accurately with the A-frame. [0218] An alternative to that is also proposed to address this process. For example, at a proximal end of the reamer shaft handle will be placed a first reference system 1205, for example a laser pointer. This laser pointer 1205 will project a spot 1210 either on a wall or on a screen 1215, a known distance from the operating room table. That spot 1210 on wall 1215 (or on the screen) is then marked with another reference system 1220, for example a second independent laser pointer that sits on a steady stand in the operating room. Thereafter manipulating the shaft handle so that the first reference system has the desired relationship, example co-aligned, with the second reference system, the surgeon knows that the device attached to the handle has the desired orientation. So when the first reamer is held in the anticipated and desired final alignment of the implant (e.g., 40 degree abduction, 20 degree anteversion for many preferred installation angles of an acetabular cup), the laser pointer at the proximal end of the reamer handle projects a spot on the wall or screen. That spot is marked with the second stationary laser, and held for the duration of the case. All subsequent reamings will therefore not require an A-frame to get a sense of the proper alignment and direction of the reamer. The surgeon assures that no matter how he moves the reamer handle in the process of reaming of the acetabulum, that the reaming finishes with the reamer handle (laser pointer) pointing to the spot on the wall/screen.. In this manner, directionality is assured during the reaming process. In this way the sinking path of the actual implant is somewhat predetermined. And no matter what final intra -operative monitoring technique is used (A-frame, C-Arm, Navigation) that the cup will likely seat/sink more closely to the desired final position.

[0219] FIG. 13 illustrates modified surgical devices 1300 incorporating vibratory energy as at least an aid to mechanical preparation. Also proposed herein is another concept to address a problem associated with non-concentric reaming of the acetabulum caused by variable densities of the bone and the uncovering of the reamer. Imagine the same carpenter has to cut through a construct that is made out of wood, air, and cement. The carpenter does not know anything about the variable densities of this construct. There are two different saws available: one that cuts effectively through wood only, and ineffectively through the cement. Also available is a second saw that cuts just as effectively through cement as wood. Which of these saws would improve a chance of producing a more precise cut? Proposed is a mixing of ultrasonic energy with the standard oscillating saw and the standard reamer. In effect any oscillating equipment used in orthopedics, including the saw, reamer, drill, and the like may be made more precise in its ability to cut and prepare bone with the addition of ultrasonic energy. This may feel dangerous and counterintuitive to some, however, the surgeon typically applies a moderate amount of manual pressure to the saw and reamers, without being aware, which occasionally causes tremendous skiving , bending and eccentric reaming. An instrument that does not requires the surgeon's manual force maybe significantly safer and as well as more precise and effective.

[0220] A further option includes disposition of a sensor in the shaft of the ultrasonic reamers and saws so that the surgeon can ascertain when hard versus soft bone is being cut, adding a measure of safety by providing a visual numerical feedback as to the amount of pressure being utilized. This improvement (the ability to cut hard and soft bone with equal efficacy) will have tremendous implications in orthopedic surgery. When the acetabular cavity is prepared more precisely, with significantly lower tolerances, especially when directionality is observed, the acetabular implant (cup) may more easily follow the intended sinking path.

[0221] Other applications of this concept could be very useful. Pressfit and ingrowth fixation in total knee replacements in particular (as well as ankle, shoulder and other joints to a lesser degree) are fraught with problems, particularly that of inconsistent bony ingrowth and fixation. The fact that a surgeon is unable to obtain precise cuts on the bone may be a significant factor in why the bone ingrowth technology has not gotten off the ground in joints other than the hip. The problem is typically blamed on the surgeon and his less than perfect hands. The experienced surgeon boasts that only he should be doing this operation (i.e.: non-cemented total knee replacement). This concept (a more precise saw that cuts hard and soft bone equally allowing lower tolerances) has huge potential in orthopedics, in that it can lead to elimination of the use of cement in orthopedic surgery altogether. This can spark off the growth and use of bone ingrowth technology in all aspects of joint replacement surgery which can lead to tremendous time saving in the operating room and better results for the patients.

[0222] FIG. 14-FIG. 22 relate to a first particular implementation of a mechanical BMD 1400 for controlled axial impact; FIG. 14 illustrates a perspective view of BMD 1400; FIG. 15 illustrates a first impact energy control mechanism 1500 for use with the particular BMD of FIG. 14; and FIG. 16 illustrates a second impact energy control mechanism 1600 for use with the particular BMD of FIG. 14. BMD 1400 includes a motor is directly connected to a cam via a gear train.

Instead of having the cam directly displace the instrument shaft, the cam an impact energy control that is positioned proximally of the shaft by means of a rocker assembly. The profile of the cam is such that the control is actuated between impacts, until a desired condition is reached and the energy is released, driving the shaft forward and generating an impact force. [0223] The mechanism of FIG. 14 may allow a device to indirectly measure the rate of insertion of an acetabular cup while controlling the impact force being delivered to the cup as described in US Patent Application No. 15/234,782 filed 11 August 2016, the contents of which are hereby expressly incorporated by reference thereto in its entirety. The method may include a handheld instrument that would include an actuator, shaft, and cup interface. Similar to the impaction rod currently used by surgeons, the instrument would couple to an acetabular cup using an appropriate thread at the distal end of the instrument shaft. The actuator would couple to the proximal end of the instrument shaft, and create controlled impacts that would be applied to the shaft and connected cup. The magnitude of the impact would be controlled by the surgeon through a dial or other input mechanism on the device, or directly by the instrument's software.

[0224] While the cup is being inserted, each blow must reach a minimum impact force in order to overcome the static friction of the cup/bone interface. The impact force required increases as the insertion depth of the cup increases due to larger normal forces acting on the cup/bone interface (see incorporated patent application). There is a balancing act though, as larger impact forces raise the risk of fracture of surrounding bone. The goal of the surgeon is to reach a sufficient insertion depth to generate acceptable cup stability, while minimizing forces imparted to the acetabulum during the process. This area is believed to be in the beginning of the non-linear regime, as higher forces begin to have a smaller incremental benefit to cup insertion (i.e. smaller incremental insertion depth with larger forces).

[0225] There are a number of challenges with developing a tool that will aid cup insertion: 1) the insertion force plot will vary for each procedure, 2) the resulting optimal depth will vary, and 3) there is no simple way to measure the insertion depth of the cup relative to the acetabulum.

[0226] The proposed solution will instead have the actuator control the amount of energy being transmitted during each impact. This could be done in a number of ways, with two examples explained below. Both mechanisms utilize the basic arrangement of BMD 1400, but could be adapted for other implementations discussed.

[0227] Energy Impact Control Mechanism - Spring Preload:

[0228] FIG. 17 illustrates a cross-sectional view of an impact energy control mechanism (spring preload) 1700 as may be used in the particular BMD of FIG. 14, and FIG. 18 illustrates an internal view of an impact energy control mechanism (spring preload) 1700 as may be used in the particular BMD of FIG. 14. The first approach would have the device compress a spring of known spring constant by retracting the instrument shaft by a fixed distance. In the figures this shaft displacement is performed via a rotating cam which in turn uses a rocker to convert the rotational motion to linear movement. The device would be able to vary the energy stored within the shaft spring for each impact by varying the amount of spring preload (i.e. the amount of spring

compression immediately after an impact has occurred).

[0229] The preload is varied using a spring compression insert. The spring compression insert includes external threads which mates to the housing of the tool. A gear head is attached to the top face of the spring compression insert, which mates to a motor via a worm gear or other appropriate mechanism (e.g. chain drive, belt drive, gear train, etc.). The vertical position of the insert relative to the shaft spring can be increased or decreased by incrementing the motor either clockwise or counterclockwise. This in turn will rotate the compression insert, which will raise or lower via its external threading.

[0230] Motor design can use a stepper motor, brushed DC, or brushless DC. Depending on the accuracy required a rotary encoder can be incorporated, being placed either on the output shaft of the spring preload motor or on the spring compression gear face.

[0231] Impact Energy Control Mechanism, Friction

[0232] FIG. 19 illustrates cross-sectional view of an impact energy control mechanism (friction) 1900 as may be used in the particular BMD of FIG. 14; FIG. 20 illustrates an internal view of an impact energy control mechanism (friction) 1900 as may be used in the particular BMD of FIG. 14; FIG. 21 illustrates a close-up detail of an impact energy control mechanism (friction) 1900, ball-detent as may be used in the particular BMD of FIG. 14; and FIG. 22 illustrates a bottom view of an impact energy control mechanism (friction) 1900 as may be used in the particular BMD of FIG. 14.

[0233] The second example would have a static spring preload, and would instead us friction to control the amount of energy transferred for each impact. The shaft spring would strike a hollow tube, which would fit over a distal instrument shaft. One or more ball plungers would be threaded through the wall of the tube, pressing onto the side of the instrument shaft. The insertion depth of the ball plungers could be controlled via a motor and ball detent control gear, which in turn would determine the friction forces between the tube and the instrument shaft. The ball detent control gear would have a cam inner profile, allowing the depth of the ball plungers to be varied depending on the rotational position of the gear. The friction force generated by the ball plungers would determine the amount of energy that would be transmitted to the instrument shaft, with any excess spring forces resulting in slip between the tube and shaft.

[0234] Acetabulum Cup Insertion Device, Slide Hammer, Hand Operated Concept

[0235] FIG. 23-FIG. 24 relate to a second particular implementation of a mechanical BMD for controlled axial impact. FIG. 23 illustrates a hand-operated slide hammer implementation for a mechanical BMD 2300; and FIG. 24 illustrates an exploded view of mechanical BMD 2300. BMD 2300 includes a fixed grip 2305, a set of travel stop adjustment grooves 2310, a slide travel stop adjuster 2315, a heavy slide 2320, a slide shaft 2325, a force sensor top 2330, a force sensor 2335, a force sensor bottom 2340, an acetabular cup 2345, a medium slide 2350, and a light slide 2355 (slides represent variable mass for varying force).

[0236] Acetabulum cup insertion involves striking an insertion shaft threaded to the replacement cup with a free-swinging hammer to seat the cup. Alignment and full seating of the cup is a trial-and-error process, involving much corrective striking of the insertion shaft to properly seat the cup. The many variables involved in this process include striking force, direction of strike on the insertion shaft, and hammer weight. If done incorrectly, damage to the patient may result. The slide- hammer insertion device is designed to minimize these liabilities by making each force input separate from the others, and by helping to constrain each force input to a controlled factor.

[0237] Each force input is separated into a controllable vector: Direction - The Slide Shaft directs the seating force of each impact. Impact Mass: The Impact Sliders come in a range of rates. The heavier they are, the greater the impact force, and the greater the "dwell time", or duration of the impact. Slide Distance: The Slide Travel Adjuster limits the acceleration and therefore the impact speed of the hammer weight. Impact Force Sensor: Indicates the force generated with each impact, giving the surgeon a comparison to the optimal desired impact for each combination of cup size and type and bone density.

[0238] Resultant Forces:

[0239] Combinations of the slide weights and the travel distance can be tabulated to take into ac- count the surgeon's strength, the patient's bone density, and the size and type of Acetabular Cup being used. Insertion direction can be adjusted between each impact to reduce the amount of corrective impact needed to properly seat the cup. A navigation system may be employed to assist in proper orientation during installation of cup 2345.

[0240] Acetabulum Cup Insertion Device, Slide Hammer, Pneumatic Concept

[0241] FIG. 25-FIG. 27 relate to a third particular implementation of a mechanical BMD for controlled axial impact; FIG. 25 illustrates a pneumatically-operated slide hammer implementation for a mechanical BMD 2500; FIG. 26 illustrates an internal view of the mechanical BMD of FIG. 25; FIG. 27 illustrates an exploded view of the mechanical BMD of FIG. 25; and FIG. 28 illustrates a detail view of the pneumatic engine for the BMD of FIG. 25. BMD 2500 includes a trigger 2505, an upper grip 2510, an air manifold 2515, a cylinder 2520, a travel adjust tube 2525, a heavy slide 2530 (inside), an impact plate 2535, a slide tube/lower grip 2540, a cup shaft 2545, a cup 2550, a medium slide 2555, ad light slide 2560 (slides interchangeable with heavy slide 2530). Pneumatic system further includes an air input 2562, an air exhaust 2564, a reset air input 2566, a reset actuation pressure control 2568, an exhaust valve 2570, a reset valve 2572, a piston actuation pressure control 2574, and a piston actuation valve 2576. Further illustrated in FIG. 26, BMD 2500 includes air actuator control circuits 2605, air actuator wiring 2610, piston and rod 2615, a slide guide 2620, and a force sensor 2625.

[0242] The current state-of-the-art acetabulum cup insertion involves striking an insertion shaft threaded to the replacement cup with a free- swinging hammer to seat the cup. Alignment and full seating of the cup is a trial-and-error process, involving much corrective striking of the insertion shaft to properly seat the cup. The many variables involved in this process include striking force, direction of strike on the insertion shaft, and hammer weight. If done incorrectly, damage to the patient may result.

[0243] The slide-hammer insertion device is designed to minimize these liabilities by making each force input separate from the others, and by helping to constrain each force input to a controlled factor. Additionally, this concept uses air to move the impact weight, making the application of force more predictable across a range of users, regardless of strength and size.

[0244] Each force input is separated into a controllable vector: Direction: The Slide Shaft directs the seating force of each impact. Impact Mass: The Impact Sliders come in a range of rates. The heavier they are, the greater the impact force, and the greater the "dwell time", or duration of the impact. Pneumatic force: is adjustable to take the user variability out of the equation. Impact Force Sensor: Indicates the force generated with each impact, giving the surgeon a comparison to the optimal desired impact for each combination of cup size and type and bone density.

[0245] Resultant Forces:

[0246] Combinations of the slide weights and the air pressure can be tabulated to take into account the patient's bone density and the size and type of Acetabular Cup being used. Insertion direction can be adjusted between each impact to reduce the amount of corrective impact needed to properly seat the cup.

[0247] FIG. 29 illustrates a BMD 2900 having bidirectional longitudinal motion; and FIG. 30 illustrates a BMD 3000 having bidirectional rotational motion. In previous discussions of BMD3 vibratory and operational devices, specific directionality controls of the movement were not addressed as described herein. Many vibratory systems are "driven" in one-direction based upon a particular application and implementation. For example, a device may be driven longitudinaly outward and have a soft/undriven inward return motion. For many instances this may not affect operation, however for some bone preparation procedures, the device may become lodged in a portion of the bone when it is driven in one direction only. As described herein, there can be advantages to having tools with intentional directionality, bidirectionality, and an ability to select directionality modes. Disclosed herein are devices that have intentionally designed and allow for, based upon application, for unidirectionality and bidirectionality, and selectivity in directionality mode selection in applied force by an oscillatory engine. For procedures and processes relating to preparing an installation site, installing a prosthesis, and revising/removing an installed prosthesis, there may be advantages in different directionalities in different contexts. Rather than having three different tools, the present disclosure contemplates a tool having multiple selectable directionalities allowing it to be used in different procedures.

[0248] Also disclosed is a new type of cavity formation tool (for hip replacement in preparation of the pelvic bone) that may advantageously employ bidirectional vibratory motion: a broach for the acetabulum cavity preparation.

[0249] BMD3 bidirectional vibratory tool: The BMD3 vibratory tool was initially created and envisioned for vibratory insertion of prosthesis into bone. During the experimentation of BMD3 vibratory tool an implementation included a case that vibratory energy can be unidirectional in forward and backward directions or it can be bidirectional. Some embodiments may demonstrate an effectiveness and use of unidirectional forward vibrating BMD3 tool for insertion of a prosthesis (in particular acetabular prosthesis) into bone. Other embodiments may make use of bidirectional BMD3 vibratory tool for the purpose of preparing bone, and in particular the acetabular cavity.

[0250] BMD3 bidirectional vibratory tool for preparation of bone, and in particular the acetabular cavity: The use of an Acetabular Broach: a new idea. BMD3 bi-directional vibratory tool can be used for preparation of bone (any cavity of bone that needs to be prepared for application of a prosthesis, but especially the acetabulum, as well as the proximal femur, proximal tibia, proximal humerus, and any other long bone in the body that receives a prosthesis). With regards to the acetabulum, unlike the other bones discussed above, this structure has never before been prepared with a broach, but rather always prepared with a hemispherical "cheese grater type" reamers that rotates in one direction (forward). An embodiment may include preparation of the acetabulum with a broach using one of the two degrees of freedom for oscillation

[0251] (1. Longitudinal and 2. rotational), utilizing a bidirectional BMD vibratory tool. The outer surface of this broach will very closely resemble the rough surface of the prosthesis, with high coefficient of static friction. Some embodiments may demonstrate this method in action, particularly at higher frequencies of around 300 hertz, and believe that this method of acetabular preparation will provide a cut surface that is much more precise and conferring the ability to produce lower tolerances. This method may also allow preparation of acetabular cavity in "half sizes. Currently the cavity is reamed in 1mm intervals. It may be much easier to prepare the acetabulum with ½ mm interval broaches than ½ mm reamers. Half size broaching may dramatically improve the ability of the surgeon to cut and prepare the acetabular precisely and at lower tolerances.

[0252] For purposes of review it is that that the equation FR is directly related to K * x * Us (sometimes it may be written FR = K * x * Us though it is not always accurate to do so). Where x is represents the amount of under reaming and the shape of the cup being inserted.

[0253] X is controlled by the amount of under or over reaming of the acetabulum. In the past when the surfaces of the cup were not as rough (lower coefficient of static friction, i.e. Zimmer Fiber Metal cup), surgeons used to under ream by 2mm. Now most companies recommend under reaming by 1mm, since the surfaces of most cups are much rougher with better porosity

characteristics that allow better and quicker bony ingrowth. Sometimes when the surgeon has difficulty seating the cup, he/she reams line to line, and describes this action as "touching up the rim". This action however, many times, eliminates the compressive quality of the acetabulum by decreasing the value of x towards zero. This issue brings attention to the problem that has been described which is that the surgeon does not have anything but a most basic understanding of the spring like qualities of bone. If he/she is can understand the basic science involved in this system, he can then use the proper tools to appropriately fine tune the pelvis for a good press fit fixation, without fear of under seating or fracture. There is a huge market need for better tools to prepare (fine tune) the acetabulum, for good press fit fixation.

[0254] Current techniques utilize 'cheese grater type' hemispherical reamers to prepare the bed of the acetabulum. As discussed in relation to BMD4, a quality of acetabular bone can be drastically different between patients and even within the same patient, particularly at different locations around the acetabular fossa. Some parts of the bone are soft, and some are hard. Current cheese grater hemispherical reamers come in 1mm intervals. This creates two specific problems: 1. The current acetabular reamers in 1mm intervals for preparation of the acetabular bone do not provide the ability to precisely machine the acetabulum , and obtain lower tolerances, and therefore proper tuning of the pelvic bone. 2. No method exists to cut hard and soft bone with the same level of effectiveness, i.e.: hard bone always pushes the reamers towards the soft bone which ends up being chewed up more, and in that sense, a perfect hemisphere is not created with current cheese grater reaming techniques. Some embodiments may include two distinct and separate solutions which can, under some situations, remedy this problem of poor quality acetabular preparation.

[0255] 1. The creation of half reamers. The production and use of half reamers gives the surgeon the ability to ream up or down by half millimeters. Which gives him/her the ability to fine tune x more precisely, and therefore FR more precisely. This basically gives the surgeon a better set of tuning forks to obtain better tension for the acetabulum and utilize its viscoelastic properties to his/ her advantage to obtain a better press fit fixation.

[0256] 2. Ultrasonic assisted reaming or broaching: Lastly, it is believed that there is some room for creating a better cutting tool by adding ultrasonic energy to either the acetabular broach described above or the acetabular half reamers described above to create an ultrasonic assisted reaming or broaching of the acetabulum for obtaining a more precise cut and at a lower tolerance. An embodiment may include this new and novel idea for preparation of the acetabulum for obtaining better tension of the pelvis for application of an acetabular prosthesis. [0257] In addition to the incorporated parent applications, embodiments of the present invention may include aspects of resistive force measurement, resistive force curves, and BMD tools that include force sensing, such as described in US Patent Application No. 15/234,782 filed 11 August 2016 which claims benefit of the incorporated '434 parent application as well as US Patent Application No. 62/355,657 and US Patent Application No. 62/353,024 and also described in US Patent Application No. 15/284,091, all of which are hereby expressly incorporated by reference thereto in their entireties for all purposes.

[0258] These applications include a description of a resistive force for insertion of a hemispherical acetabular cup into an under reamed cavity. This resistive force is sometimes referred to as the FR curve, defining a "cup print" for the insertion parameters. This resistive force has been described as being variable with three distinct sections. It has a profile that may be described as an "exponential curve". There is an identification of an early section/part of this FR curve where poor insertion and pull out forces exist. There is an identification of a middle section (a sweet spot) on this FR curve where good insertion and extraction forces are achieved. And, finally, the discussion describes that using larger forces beyond the sweet spot provide little additional benefit to the strength of fixation, and may increase a risk of fracture. In one analogy, this FR curve may represent a dangerous peak such as Mount Everest having five base camps. In the discussion, there is an observation that an orthopedic surgeon should be content to stop at base camp 3 or 4, and perhaps should not attempt to summit, when trying to obtain press fit fixation of the cup in an under-reamed cavity. This phenomena has been described in association with BMD3 and BMD4.

[0259] There is a very serious problem in orthopedics. Some of the incorporated patent applications discuss trunnionosis in connection with material regarding "BMD4" and "Intelligent Prosthesis Two". There are fundamental problems related to trunnionosis in orthopedics, specifically on the insertion of a femoral and humeral head onto the trunnion and the related problems that have been so far described as tribocorrosion. There many who believe that the mechanism of taper corrosion is best characterized as mechanically assisted crevice corrosion.

Fretting initiated crevice corrosion in tapers is a complex problem and the severity is dependent on multiple factors. Corrosion has been associated with clinical complications, such as elevated metal ion levels, persistent pain, tissue damage, and early implant failure.

[0260] Regardless of the design, including shorter and slimmer trunnions and larger heads, as well as taper angles (including positive and negative mismatch) there appears to be some universal problems with the process of head impaction onto the trunnion that have to do with "taper impaction technique" and the "engagement of the modular taper interface" that doom the trunnion interface to failure.

[0261] Described herein are problems associated with head/trunnion impaction and possible solutions. Vibratory insertion of a prosthetic acetabular cup is extended here in that some of the same fundamental problems associated with mallet based impaction techniques of the prosthetic acetabular cup are present here with head/trunnion impaction.

[0262] Noted below are four specific and fundamental problems with current techniques of head to trunnion impaction:

[0263] A) Inconsistent magnitude of force. The force is delivered by a surgeon using a mallet. There is no standardization of magnitude of force. There is no guidance as to how much force needs to be delivered. The medical device companies have not done In Vitro studies to determine how much force to deliver for a good seal. There is no a priori information as to what type of force produces a desired "cold weld", which appears to be what some embodiments may need or desire to accomplish strong fixation with no micro-motion.

[0264] B) Inconsistent direction of force. Non-axial alignment of force is the norm for head to trunnion impaction. This produces "canting" which leads to micro motion and corrosion.

[0265] C) Impacting against a soft object. The impact is not "elastic" but "inelastic" or plastic. The kinetic energy produced by the surgeon and the mallet is mostly lost in a system that is inelastic. Momentum is conserved in that much of the energy produced by the surgeon and the hammer is dissipated by the spring like quality of the whole leg/femur/thigh/prosthesis complex. But kinetic energy is not conserved, with most of the energy lost by the system described above, and therefore, the transfer of energy from the head to trunnion interface is highly inefficient.

[0266] D) Assuming a surgeon is able to get the right amount (magnitude) of force delivered with the right technique (perfectly axially), how do you know you have actually achieved a "cold weld"? How do you know when to stop application of Force? No In Vitro studies have ever been done to guide the surgeon as to how much force to apply. Also, a proper tool have never been provided to the surgeon to accomplish this job.

[0267] The solution may include a new design with several key features. [0268] 1) A head may include a flat edge that allows it to sit flat on a table. A "head holder" may grasp the head in a 'normal' fashion on the flat edges. On an opposite side of the head holder a center axis point may be created, which allows ONLY central axis application of force.

[0269] 2) The force as will be described can be delivered dynamically through controlled impaction as with BMD4 technique (e.g., various slide hammer configurations), or vibratory insertion as with BMD3 techniques or with Constant insertion (to allow the system to mostly deal with friction (e.g., a coefficient of kinetic friction Uk).

[0270] 3) The prosthesis may have either indentations, holes, or ridges created in it to allow an insertion apparatus (BMD5) to purchase and grasp the prosthesis. This is a way to avoid unnecessary loss and waste of kinetic energy.

[0271] 4) A force sensor/torque wrench/strain gauge within the tool measures the force experienced within the tool/head/trunnion/prosthesis complex.

[0272] 5) An amount (magnitude) of force required to obtain a perfect weld can be determined in vitro. The force can be delivered with controlled impaction, vibratory insertion, or constant insertion. The force sensor may, in some implementations, act much like a torque wrench (possibly) stopping the application of the perfectly tuned force (both magnitude and direction) when a cold weld is obtained. Little to no dissipation of force/energy may occur in this system. The inconsistencies that are introduced by the surgeon and the mallet with current techniques are eliminated entirely. Since the surgeon is told in advance how much force to deliver and given the proper tool to accomplish this job, it is impossible to deliver less than required force. Since the tool only applies perfectly axial force, no canting can occur. Since the head and trunnion are now coupled/constrained in one physical system, wasting of kinetic energy will reduced or eliminated. The insertion of the head onto the trunnion is now done with a technologically intelligent and reliable system.

[0273] In each of FIG. 31-FIG. 33, an embodiment of a BMD5 tool will be used to help assemble a modular prosthesis. This is similar to the discussion of FIG. 7. In FIG. 7, modular prosthesis 700 was assembled using assembly tool 705 while in these discussions, a BMD5 tool replaces tool 705 (with an optional modification to prosthesis 700). Prosthesis 700 includes a head 710 and a trunnion taper 715 at an end of a stem 720 (e.g., a femoral stem for supporting a ball head to fit within an acetabular cup used in a total hip replacement procedure). During some embodiments of this alternative procedure, the surgeon assembles prosthesis 700 by using a BMD5 tool. The surgeon uses the BMD5 tool to drive, and cold weld, head 710 onto trunnion taper 715.

[0274] FIG. 31 illustrates a first embodiment for a BMD5 tool 3100 used in cooperation with assembly of modular prosthesis 700 to install head 710 onto trunnion taper 715 at an end of stem 720. Prosthesis 700 is modified to include a grip structure 3105 (e.g., an indentation, hole, cavity, aperture, and the like) to allow engagement of a retention structure (e.g., a claw, grasper, gripper, and the like - represented by G) coupled to both tool 3100 and to prosthesis 700. Optional grip structure 3105 may be used to reduce or eliminate wasting of kinetic energy during assembly and welding of head 710 onto taper 715.

[0275] BMD5 tool 3100 includes a head grasper 3110, an in-line force sensor module 3115, a torquer 3120, and torque converter 3125. Head grasper 3110 retains and aligns head 710 into an optimum installation orientation (e.g., perpendicular/normal) to allow application of force only along an assembly axis 3130 joining, and aligned with, grip structure 3105, head 710, taper 715, grasper 3110, module 3115 and torque converter 3125. This alignment allows for only force application only along assembly axis 3130 which prevents/reduces canting. Gripper G is illustrated as being functionally connected to grasper 3110, but could be mechanically communicated to another portion or component of tool 3100. This is a functional representation as there may be several mechanical ways to implement this function, including allowing relative displacement of the grasper and trunnion while maintaining the desired alignment(s).

[0276] Grasper 3110 is important in positioning (including alignment and relative orientation) of head 710 and trunnion 715. Head 710 includes an aperture, typically complementary to the taper of a mating surface of trunnion 715. Grasper 3110 secures head 710 for assembly in a very simple and efficient manner that positions, without relative canting, head 710 and trunnion 715.

[0277] Module 3115 may include a torque wrench/strain gauge allowing a surgeon to understand one or more forces in play, such as knowing exactly how much force needs to be, and is being, delivered to obtain perfect cold weld of head 710 onto taper 715.

[0278] Torquer 3120 may include a manual or motorized source of force or torque, such as a torque engine which may include a rotary motor. [0279] Torque converter 3125 transforms torque of torquer 3120 into axial-exclusive linear force for module 3115. When the torque engine provides rotary force, converter 3125 may include a linear motion converter to alter the rotary force into an axially-aligned linear force.

[0280] In operation, femoral head 710 may be joined to trunnion taper 715 using constant insertion. That is, head 710 is "press-fit" with application of a constant (but potentially variable) axial force. This is distinguished from application of one or more discrete impacts or impulses onto grasper 3110. Constant insertion strongly implicates Uk (coefficient of kinetic friction) which may be less than a series of discrete impacts that more strongly implicate a coefficient of static friction. In some cases, stem 720 is installed into bone and thereafter tool 3100 is used to install head 710 onto the taper of trunnion 715 to obtain a sufficient mechanical connection. Herein, that mechanical connection is sometimes referred to as a "cold weld" which for purposes of this application means that head 710 and trunnion 715 are engaged enough that relative micro-motion is eliminated or sufficiently reduced that risks of relative micro-motion are reduced below a predetermined threshold.

[0281] This is one aspect of the present invention, that a manufacturer of modular prosthetics may develop, or share, information on the forces necessary to produce a cold weld as noted above. Without recognition of the problems noted herein and a BMD5 tool to measure and/or control assembly forces and a surgeon swinging uncalibratingly a mallet to freely strike head 710 and drive it onto trunnion 715, there was insufficient need or motivation to develop or share this type of information.

[0282] FIG. 32 illustrates a second embodiment for a BMD5 tool 3200 used in cooperation with assembly of modular prosthesis 700 to install head 710 onto trunnion taper 715 at an end of stem 720. Tool 3200 varies from tool 3100 in that tool 3200 performs insertion using a vibration profile. The vibration profile is provided by a vibration engine 3205 that may include a rotary motor 3210 coupled to a linear motion converter 3215 to impart a vibration to head grasper 3110 (and then to head 710) to insert and cold weld head 710 onto trunnion taper 715. There are other ways to implement vibration engine 3205.

[0283] In operation, tool 3200 may join head 710 to taper 715 with a vibratory force

(implicating a blend of static and kinetic coefficients of friction - Us and Uk), which may require less force than a series of discrete/dynamic impacts onto head 710. [0284] FIG. 33 illustrates a third embodiment for a BMD5 tool 3300 used in cooperation with assembly of modular prosthesis 700 to install head 710 onto trunnion taper 715 at an end of stem 720. Tool 3300 varies from tool 3100 in that tool 3300 performs insertion using an impact profile. The impact profile is provided by an impact engine 3305 that may include a slide hammer 3310 having an axially-limited sliding mass to impart a discrete impact onto a shaft 3315 and by that mechanism to head grasper 3110 (and then to head 710) to insert and cold weld head 710 onto trunnion taper 715. There are other ways to implement impact engine 3305, including manual, mechanized (e.g., robotic), and semi-mechanized solutions.

[0285] In operation, tool 3300 may join head 710 to taper 715 with a series of one or more discrete impacts from impact engine 3305 (implicating predominantly/exclusively static coefficient of friction Us).

[0286] In summary BMD 5 is a tool that:

[0287] 1. Advantageously modifies a femoral prosthesis in such a way to allow a grasp or engagement of the prosthesis by the BMD5 tool. This can be accomplished in a variety of ways: A hole, dent, ridges, and indentations can be created on the prosthesis. The ability to grasp the prosthesis is important in some embodiments in that it prevents, or reduces, waste of kinetic energy.

[0288] 2. The BMD5 tool may include a "head grasper" which holds the femoral or humeral head in a perpendicular or "normal" fashion. This allows the force of insertion/impaction to be applied perfectly axially, without the risk of "canting".

[0289] 3. The BMD5 tool has a torque wrench/strain gauge/force sensor of a wide variety of possible types that measures an amount of force applied through the tool/head/trunnion/prosthesis complex. The surgeon will always know exactly how much force is being applied. The amount of force required to obtain a perfect "cold weld" can be predetermined in the laboratory. The surgeon can simply apply the force that is recommended by the medical device company to obtain a perfect cold weld every single time, eliminating all variability that is currently present with application of force with variable surgeon strengths and mallet sizes.

[0290] 4. For Constant insertion, manual or motorized rotatory motion is converted into linear motion with any linear motion converter. In a simple form, the rotatory motion of a screw/thread is converted into linear compression. For Vibratory insertion, similarly, rotatory motion by a motor is converted into linear vibration. For Discrete Impacts a sliding mass of known weight can travel over a known distance to deliver a predetermined amount of force.

[0291] BMD5 may include a self-contained system that reduces any wasting of energy. BMD5 may allow for perfect axial delivery of force while providing for quantitative measurement of applied/communicated/transmitted force(s). So stakeholders can rest assured that every step has been taken to obtain a cold weld at the trunnion/head interface. Embodiments of BMD5 may allow a surgeon to cold weld the femoral head onto the trunnion simply, efficiently, and accurately while minimizing risks of improper installation. Some embodiments of BMD5 may include ultrasonic press-fitting, such as described in Csaba LAURENCZY et al., "ULTRASONIC PRESS-FITTING: A NEW ASSEMBLY TECHNIQUE" S. Ratchev (Ed.): IPAS 2014, IFIP AICT 435, pp. 22-29, 2014, hereby expressly incorporated by reference in its entirety for all purposes.

[0292] FIG. 34 through FIG. 40 illustrate a particular implementation of a mechanical alignment system for use with an embodiment of a BMD5 tool, such as, for example, those illustrated and/or described herein. FIG. 34 illustrates a side view of a prosthetic body 3400 to be mechanically joined to an installable prosthetic head. Body 3400 includes a stem portion 3405 for insertion into a prepared bone and a taper portion 3410 for mechanical joinder to a selected installable prosthetic head. A center line 3415 is defined as a central axis of taper portion 3410. Taper portion 3410 may include a two-dimensional symmetry along a length of center line 3415. The installable prosthetic head will include a complementary taper cavity that may further match this two-dimensional symmetry over a depth of the taper cavity along a taper cavity center line.

Maintaining an alignment of these center lines as the prosthetic head is mechanically joined to taper portion 3410 may reduce, minimize, and/or eliminate canting or dangerous installation conditions that may contribute to or exacerbate any trunnionosis related to assembly of the prosthetic head onto taper portion 3410. Body 3400 may include, as a grip structure, a non-traditional through-hole 3420 centered on center line 3415 proximate taper portion 3410.

[0293] In some embodiments, grip structure 3420 may not be a through hole but may include, for example, laterally opposed divots with each centered on center line 3415. In other embodiments, the grip structure may include a conventional non-center line aligned element 3425. An adaptor, jig, or engagement system cooperating with element 3425 may provide a predetermined offset to align such other assembly components with center line 3415. [0294] FIG. 35 and FIG. 36 illustrate a set of views of a prosthetic head 3500 to be installed on taper portion 3410 of prosthetic body 3400. FIG 35 illustrates a top view of prosthetic head 3500 and FIG. 36 illustrates a side view of prosthetic head 3500. Prosthetic head 3500 defines an outer spherical surface 3505, at least a hemisphere, and further includes a planar face 3610, offset from but generally parallel to a diameter of the spherical portion of head 3500. An aperture is defined in planar face 3610, this aperture provides an opening into a taper cavity 3515 disposed within prosthetic head 3500. Taper cavity 3515 is designed to mate and engage with taper portion 3510 and in this sense is referred to herein as being complementary. Taper cavity 3515 also defines a taper cavity center line 3520 also having a two-dimensional symmetry along a depth of taper cavity 3515, and in some cases taper cavity center line 3520 is perpendicular to planar face 3610. An optional feature includes a marking, for example, a laser etch or other patterning modality, that applies a visible set of "cross hairs" 3525 centered on taper cavity center line 3520.

[0295] A goal of the supporting structures of some embodiments of the present invention may include configuring alignment of center line 3420 with center line 3520, maintaining that alignment while taper portion 3410 is mechanically joined with taper cavity 3515, and in some cases monitoring a magnitude of applied assembly forces to achieve a desired mechanical join (e.g., a cold weld or the like).

[0296] While the cross sections along a length of the center lines for both taper portion 3410 and taper cavity 3515 are circular, other cross sectional shapes may be employed without departing from the present invention.

[0297] FIG. 37 through FIG. 40 illustrate a set of views for an anvil 3700 intended to impart an assembly force to prosthetic head 3500 relative to prosthetic body 3400. FIG. 37 illustrates a side view of anvil 3700, FIG. 38 illustrates a top view of anvil 3700, FIG. 39 illustrates a bottom view of anvil 3700, and FIG. 40 illustrates a sectional view through anvil 3700 at A-A of FIG. 37. Anvil 3700 includes a solid body 3705 having a circumferential channel 3710 extending completely around an outside of a lateral sidewall of body 3705. Body 3705 includes a top face 3715 and a bottom face 3720 spaced apart from top face 3715 by the sidewall. A spherical sectional depression 3725 is defined in top face 3715. Depression 3725 is complementary to outer spherical surface 3505. Depression 3725 has a depth to position the planar face of prosthetic head 3500 into a predetermined relationship with top face 3715. In some instances, bottom face 3720 may define a tap or aperture 3905 that is centered at a longitudinal axis 4005 of body 3705 that extends through top face 3715 and bottom face 3720 and automatically aligns with taper cavity center line 3520 when prosthetic head 3500 is installed into mating depression 3725. Bottom surface 3720 supports an anvil axis interaction structure, such as tap or aperture 3905 and/or other structure, which may be used for visual confirmation of axial alignment with indicia 3520, or may be used for receipt of a force applicator, or some additional or other interaction with anvil 3700.

[0298] In some embodiments, aperture 3905, the optional structure, may extend from bottom surface 3720 into depression 3725. When so provided, and when prosthetic head is further provided with optional cross hairs 3525, it is possible to confirm alignment of axis 4005 with center line 3520 when cross hairs 3525 are visible in aperture 3905.

[0299] FIG. 41 through FIG. 45 illustrate a set of views of a multi-part adaptor 4100 for securing anvil 3700 to prosthetic head 3500. FIG. 41 illustrates a side view of multi-part adaptor 4100, FIG. 42 illustrates a top view of multi-part adaptor 4100, FIG. 43 illustrates a bottom view of multi-part adaptor 3700, FIG. 44 illustrates a sectional view through multi-part adaptor 3700, and FIG. 45 illustrates an enlarged view of FIG. 44. As illustrated, multi-part adaptor 4100 includes two half-shells (half-shell 4105 and half-shell 4110, each half-shell a mirror image of the other) though other configurations may provide for a different number of parts and differing configurations.

[0300] These are half-shells because they each include a rigid exterior wall cooperatively defining an interior cavity 4405 that is sized and configured to secure and hold prosthetic head 3500 within depression 4005 of anvil 3700 while center line 3525 is aligned with axis 4005. Adaptor 4100 defines a top face 4115 and a bottom opening 4120. Top face 4115 defines an aperture 4205 for receipt of taper portion 3410 when prosthetic head 3500 is installed into depression 4005 of anvil 3700 and both head 3500 and anvil 3700 are installed into cavity 4405.

[0301] Interior portions of the walls of adaptor 4100 further define an interior circumferential ledge 4410 that is designed to mate to circumferential channel 3710 when adaptor 4100 secures anvil 3700 and head 3500. A distance from ledge 4410 to top face 4415 is based upon a height of the planar face of head 3500 above depression 4005 when head 3500 is installed in anvil 3700 with axis 4005 aligned with center line 3525. By matching the distance to the height, top face 4115 will automatically align center line 3525 with axis 4005 when the half-shells are closed down on head 3500 and anvil 3700. [0302] As further detailed in the enlarged view of adaptor 4100 in FIG. 45, aperture 4205 in top face 4115 may be formed with sloped edges to match an angle of taper portion 3410.

[0303] As illustrated, adaptor 4100 may be configured to a particular one size of prosthetic head 3500. When a differently sized prosthetic head 3500 is to be installed on taper portion 3410, a different adaptor 4100 may be used and in some embodiments, this is the only modification that need be made to the system to accommodate differently sized heads. Similarly, with proper attendance to the configuration options, different sized bodies may be matched to different sized heads by only varying adaptor 4100 in appropriate fashion.

[0304] FIG. 46 through FIG. 48 illustrate a set of views of a clamp 4600 for attachment to prosthetic body 3400 and apply an aligned assembly force to prosthetic head 3500 by use of multipart adaptor 4100. FIG. 46 illustrates a top view of clamp 4600, FIG. 47 illustrates an end view of clamp 4600, and FIG. 48 illustrates a side view of clamp 4600. Clamp 4600 includes a "U-shaped" body 4605 having a first leg 4610, a second leg 4615, and a bridge 4620 coupled to each leg. A distal end of each leg defines an aperture 4625 that are aligned with each other.

[0305] Bridge 4620 defines a force application structure 4630 for allowing an assembly force to be transferred from outside of clamp 4600 to a location disposed between the legs. In FIG. 47, structure 4630 includes a tapped/threaded interior surface to allow a complementary threaded bolt to pass into the location. FIG. 48 illustrates that in this implementation, structure 4630 is aligned with apertures 4625.

[0306] As noted herein, there may be many different types of assembly forces used and therefore the transfer structure may need to be adapted accordingly to accommodate the particular assembly force in use. For example, in some cases, a simple aperture may be used and other cases clamp 4600 may be part of a robotic system, among other variations.

[0307] FIG. 49 illustrates a stackup view for a mechanical alignment system 4900 shown securing, aligning, and applying an assembly force F to prosthetic head 3500 to install it onto prosthetic taper 3410. A pin 4905 is illustrated that is passed through aligned apertures 4625 and structure 3420 which aligns to center line 3415 and secures the components to prosthetic body 3400.

[0308] A representative assembly force F is applied by use of a screw 4910 threaded through structure 4630. A pad 4915 at a distal end of screw 4910 contacts anvil 3700 and helps to distribute assembly force F when applied against the assembly including head 3500, anvil 3700, and adaptor 4100. Assembly force F, applied on a force application axis 4920 is automatically aligned with center line 3415 as is the taper cavity of head 3500.

[0309] As screw 4910 is rotated, it is advanced into the space between the legs of clamp 4600 which transfers assembly force F onto the assembly that includes prosthetic head 3500.

Assembly force F causes head 3500 and taper portion 3410 to join together without tilting, canting, or off-axis torqueing impacts, such as is often applied from a mallet.

[0310] During joinder of head 3500 and taper portion 3410, as assembly force F increases at some point a desired mechanical join is achieved. In some cases, this mechanical join may include a desired cold weld with reduced risk of trunnionosis. As noted herein, in some cases it may be desirable to continue to increase assembly force F until a desired assembly force profile is achieved.

[0311] FIG. 50 illustrates a representative manual torque wrench 5000 which may be used with the system illustrated in FIG. 49 to apply a predetermined assembly force, or assembly force profile to produce a desired mechanical join of prosthetic head 3500 onto prosthetic body 3400.

[0312] FIG. 51 illustrates a side view of an alternative prosthetic body 5100 to be

mechanically joined to installable prosthetic head 3500. Body 3400 includes a stem portion 3405 for insertion into a prepared bone and a modular taper portion 3410 for mechanical joinder to selected installable prosthetic head 3500. A center line 3415 is defined as a central axis of modular taper portion 3410. Modular taper portion 3410 may include a two-dimensional symmetry along a length of center line 3415. Installable prosthetic head 3500 will include a complementary taper cavity that may further match this two-dimensional symmetry over a depth of the taper cavity along a taper cavity center line. Maintaining an alignment of these center lines as prosthetic head 3500 is mechanically joined to taper portion 3410 may reduce, minimize, and/or eliminate canting or dangerous installation conditions that may contribute to or exacerbate any trunnionosis or tribocorrosion related to assembly of prosthetic head 3500 onto taper portion 3410 and installation of modular trunnion 3410 into body 3405. Body 3400 may include, as a grip structure, a non-traditional through-hole 3415 (or detent/depression/extension/pin or other physical structure centered on center line 3415.

[0313] In some embodiments, grip structure 3415 may not be a through hole on center line 3415 but may include, for example, laterally opposed divots with each centered on center line 3415. In other embodiments, the grip structure may include a conventional non-center line aligned element 3425 which may have optionally been provided for removal of body 3400 when installed. An adaptor, jig, or engagement system cooperating with element 3425 may provide a predetermined offset to align such other assembly components with center line 3415.

[0314] Differences between body 5100 as compared to body 3400 may include one or more of the following possible elements. Illustrated in FIG. 51 is use of modular taper portion 5110 in which the modular prosthesis may include three interchangeable elements: stem, trunnion taper, and head (FIG. 51) as compared to two interchangeable elements: integrated stem/trunnion and head (FIG. 34).

[0315] Modular trunnion taper 5110 may be a separate element that includes taper portion 5110 coupled to a trunnion extension 5120. Trunnion extension 5120 is designed to be inserted into and received and secured by a complementary trunnion extension channel defined in stem 5105. Trunnion extension 5120 may also include a center line and may also use an extension taper for mechanical joinder of modular trunnion taper onto stem 5105. The system described herein may be used to center and axially install modular trunnion taper 5110 into the channel of stem 5105.

Modular trunnion taper 5110 may optionally include a visible indicia marking a center line of trunnion extension 5120 to aid in non-tilting/non-canting installation of extension 5120 into the channel of stem 5105.

[0316] As illustrated, a centerline of extension 5120 is aligned with center line 3415 of modular trunnion portion 5110 and grip structure 3420 or grip structure 5115 may be used for installation of both elements (extension 5120 into the channel and then head 3500 onto modular trunnion portion 5110 thereafter). Alternatively, extension 5120 may be provided with a grip structure and head 3500 first installed onto modular trunnion portion 5110 and then the subassembly of head 3500 and modular trunnion portion 5110 thereafter installed onto stem 5105.

[0317] In some cases, a more complex assembly system results when a center line of extension 5120 is not aligned with center line 3415 of modular trunnion portion 5110 but the system described herein may be suitably adapted for assembly, including but not limited to multiple grip structures aligned with each center line (or variable jigs for proper offset at each stage of assembly). [0318] There are a number of functions may be achieved by the assembly system including establishment and maintenance of alignment of all axes during assembly, reduce inefficient use of assembly forces, and provide for measure of assembly force(s) used during assembly.

[0319] Reduction of inefficient energy usage may be achieved by the mechanical coupling of the two elements being joined (e.g., stem and head, stem and modular trunnion, head and modular trunnion, subassembly of head/modular taper and stem, and the like). This is contrasted to a conventional approach of installing a stem into a patient bone and then using a mallet to hammer a head onto the stem - some of the kinetic energy is absorbed by the bone, body portion, operating table, and the like. By mechanically linking one portion to the other during the assembly, this loss of assembly energy is reduced or eliminated.

[0320] Another function of establishment and maintenance of axial alignment may be achieved by awareness of axes and ensuring that these axes are aligned as assembly forces are applied. As noted, the various structures, systems, and processes described herein aid in the establishment and confirmation, in some cases this is done automatically, of alignment before and during application of force assembly. The definition and establishment of predetermined center line(s), fixing structures to these center line(s), and ensuring that appropriate axes are aligned to the appropriate center line(s) during application of the assembly force(s).

[0321] Body 5100 of FIG. 51 differs from body 3400 of FIG. 34 not only from the description of the optional modularity of the trunnion portion, but further illustration of an optional use of a non-circular grip structure. Grip structure 3420, as implemented in FIG. 49, allows clamp 4600 to rotate about pin 4905 because pin 4905 may act as axle or pivot. In some cases, such as when there is some misalignment of an application of force to the center line(s) of center line 3415, this misalignment may contribute an undesired tilting, canting, or other non-aligned assembly as the assembly force is applied.

[0322] Body 5100 provides grip structure 5115 with an irregular perimeter that inhibits or prevents rotation. As illustrated, grip structure 5115 includes a polygon (e.g., an N-sided regular polygon, N an element of an integer set {3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or more} of sides, N = 3 for in FIG. 51. The irregular perimeter need not be a regular polygon, it may be an irregular polygon. In other instances, it may be an oval, oblong, ovoid, or other non-circular perimeter. [0323] In other implementations, anti-rotation may be provided by use of two or more grip structures that are spaced apart from any other grip structure, when the multiple grip structures are used concurrently during application of an assembly force. One or both of these grip structures may include a circular perimeter.

[0324] As illustrated, the prosthesis bodies (body 3400 and body 5100) are illustrated for use in shoulder (e.g., humerus) and hip (e.g., femur) modular prosthetic assemblies. There are other modular prostheses systems in which there are mechanical joinders of multiple prosthesis components. Whenever there are two prosthesis components that must be mechanically joined together, some embodiments of the present invention may be applied to axial assembly of these other modular prosthesis systems. For example there are modular systems for knee, ankle, wrist and other joints and skeletal systems that may benefit from use of the present invention when a body (not limited to a stem or the like) is joined to another modular component.

[0325] Regarding ultrasonic assisted bone preparation in orthopedics, there is a problem with preparation of bone in joint replacement: these procedures are typically performed using

conventional orthopedic equipment such as 1) saw, 2) broach, 3) reamer, and 4) burr.

[0326] FIG. 52 - FIG. 55 illustrate a set of standard orthopedic bone preparation tools, FIG. 52 illustrates a perspective view of a powered bone saw 5200, FIG. 53 illustrates a broach attachment 5300 for a powered reciprocating bone preparation tool, FIG. 54 illustrates a hand- operated reamer 5400, and FIG. 55 illustrates a set of bone preparation burrs 5500. Conventionally, these tools include an operating motion with one degree of freedom (e.g., saw 5200 has a blade that moves laterally, broach attachment 5300 reciprocates longitudinally, reamer 5400 and the burrs of set of burrs 5500 each rotate about a longitudinal axis).

[0327] As noted below, these bone preparation tools may be enhanced by adding an additional vibratory motion component, preferably but not necessarily required, that is "orthogonal" to the conventional cutting motion. Saw 5200 includes a laterally reciprocating cutting blade that may be ultrasonically enhanced by an additional ultrasonic vibratory motion in one of the other five degrees of motion (e.g., vertical, longitudinal, or vibratory rotations of the blade such as pitch, yaw, and/or roll). Similarly each of the conventional tools has a primary mode of freedom of motion for the bone processing and an enhancement may be made by adding an additional vibratory motion in one or more other modes of freedom. Embodiments of the present invention may include an additional vibratory motion, in the primary mode and/or the additional mode(s) that may be imperceptible visually (a very small amplitude and/or very fast about or beyond 20,000 hertz).

[0328] During bone preparation, two types of bony surfaces are generally encountered which include flat surfaces and contained surfaces. For the flat surfaces, seen in knee replacement, (end of the femur or the top of the tibia) saw 5200 is used to cut the bone. For the contained surfaces (such as the acetabulum and the proximal femur), as in hip replacement surgery, broach attachment 5300 or reamer 5400 is used to prepare the bone.

[0329] A problem with all of these techniques is that the density of the bone is not uniform between patients and even within the same compartment or joint of a single patient. The bone can be very soft or very hard and vary from region to region. With hard bone, saw 5200 may "skive" which causes an uneven cut surface and which minimizes that chance of successful "porous ingrowth". This fact may be a principle reason that cement is still used in knee replacement. For the contained bone cavities such as the acetabulum and proximal femur a "goldilocks" situation exists. During preparation, a surgeon may desire to know how with confidence to prepare the bone to provide just the right amount of compressive (fit). Not too loose and not too tight. Too loose leads to loosening and potential infection of the prosthesis. Too tight leads to either poor seating (which can lead to failure of fixation) or fracture (which leads to loss of press fit fixation and loosening).

[0330] Current art does not provide a reliable and consistent tool or method for the orthopedic surgeon to reliably prepare a (variable density bone) in order to obtain a "perfect" fit for the prosthesis, whether the bone is flat as in the tibia in knee replacement or contained as in the acetabulum in hip replacement.

[0331] For contained cavities such as the acetabulum, US Patent application 15/234,782 filed 11 August 2016 (all the content hereby expressly incorporated by reference thereto in its entirety) described a basic estimation of the compressive forces involved in bone. This was named a compressive force and developed an FR curve where FR is related Fn * Us; where Fn represents the normal forces and Us represents the coefficient of static friction. Vis a vis Hooke's law the FR is directly related to K * x * Us. Where K represents the material properties of bone (the spring like quality of bone) and x represents the amount of under-reaming of bone compared to an oversized prosthesis intended for press fit. [0332] This current discussion mostly concerns itself with the variable "x" which represents the spring like quality of bone. In Hooke's law F = k * x; k is the spring's constant and x is amount of stretch placed on the spring. In orthopedic bone preparation k is represented by the material properties of bone and x is represented by the difference between the diameters of the prepared bone versus the prosthesis to be press fit.

[0333] As stated herein and in some of the incorporated applications, the surgeon and industry both appear to have a poor understanding of the basic science of the prosthesis/bone cavity interaction. It is believed that x can be more tightly and precisely machined to give a better tuning of the bone, which is to accept an oversized prosthesis.

[0334] The following further elaborates upon ultrasonic assisted preparing, milling, burring, sawing, broaching, reaming, and the like in order to obtain a more precise and efficient process of bone preparation in joint replacement surgery.

[0335] Another important advance in orthopedics is the use of robotics in the operating room. Sensors and computer-controlled electromechanical devices are integrated into a robot with a haptic sense, where robotic manipulators now have a complete spatial sense of the patient' s bone in the operating room, sometimes to within a half millimeter of accuracy.

[0336] Currently robots such as the Stryker Mako robot use a standard rotating burr, reamer or a standard saw to prepare the bone for application of a knee or hip prosthesis. The term "robot" has a special meaning in the context of preparation of live bone in a living patient. Currently it is impermissible to automate any cutting of the live bone. Robot in this sense operates as a realtime constraint that provides haptic feedback to the surgeon during use when certain movements of the processing tool are outside predetermined limits.

[0337] An advantage of the robot is that it is helps in processing bone to within less than half a millimeter. This means that the surgeon cannot easily push the burr, reamer or saw out of the allowed haptic plane. In a sense, with the robot, the cutting tool is in safer hands. These standard tools (burr, saw, and reamer) provide no particular advantage for the robotic system, that is, the conventional robotic system uses conventional tools with the constraint haptic system. A

disadvantage of the robot is that the process of cutting bone with a burr, saw and reamers are very inefficient (slow) especially in hard sclerotic bone. The robot is also very a bulky piece of equipment that adds time to the operation. Mako or other robotic knee surgeries have been somewhat adopted in the uni-compartmental knee replacement procedures (less than 10% of surgeons), and is currently being investigated for use in total knee replacement (Not yet in general markets). The use of the Mako robot in hip replacement however, has shown a very poor adoption rate; less than 0.01% of surgeons have used the Mako robot for hip replacement. Some of the weakness of this robotic procedure is in the process of 1) bone preparation and 2) the actual insertion of the prosthesis into bone.

[0338] Earlier tools have addressed tools for installing an acetabular cup into the bony cavity with either "vibratory-BMD3"technique or "discrete impact- BMD4"technique. These solutions are believed to largely eliminate the problems associated with insertion of the prosthesis, providing the ability not only to insert but also to position the prosthesis in proper alignment. Other tools have dealt with manipulating the value of Us, coefficient of static friction, during a process of insertion.

[0339] An embodiment of the present invention may include a better job of preparation of bone. In effect, some embodiments provide a tool or process that more precisely manipulates the value of x in the formula: FR related to K * x * Us. A goal of some embodiments of the present invention is to obtain lower (tighter tolerances) and do it more quickly, with different tools and methods such as disclosed herein.

[0340] An embodiment of the present invention may include bone preparation using robotic surgery through use of haptic control and management to provide an unprecedented level of safety and accuracy coupled with modified equipment that more efficiently prepares in-patient bone while offering novel solutions for bone preparation. In some of these implementations the robotic haptic feedback may be exploited by addition and utilization of a more powerful and efficient bone cutting tool/method never before used or contemplated in orthopedics as it would have been too easy to mis- process a bone portion.

[0341] Ultrasonic motion may be added to traditional bone processing tools (e.g., to the tools of FIG. 52 - FIG. 55) to offer effective non-traditional bone processing tools. This addition of ultrasonic energy to standard cutting, milling, reaming, burring and broaching techniques can be used to provide (methods and tools) in orthopedic surgery to remove bone more effectively with a (higher material removal rate) MMR and with significantly less force, and therefore more efficiency.

[0342] Specifically, in hip replacement surgery the traditional reamer, broach or burr can each be equipped with an ultrasonic transducer to provide an additional ultrasonic vibratory motion (e.g., longitudinal axial ultrasonic vibration). These new cutting methods can then be incorporated within, or in association with, a robot that only allows operation of the tool within safe haptic zones. This ultrasonic robotic cutting tool is therefore more powerful, fast and precise. It would cut hard and soft bone with equal efficiency. Additionally, the robotic operation of an ultrasonic assisted cutting tool is safe, in that the robot does not allow operation of the tool outside of the haptic safe planes.

[0343] For example, a Mako robot may be equipped with a rotatory ultrasonic bone preparation tool, operating a bone processing tool (such as single metal-bonded diamond abrasive burr) that is ultrasonically vibrated, for example in the axial direction while the burr is rotated about this axis. This tool can prepare both the proximal femur and acetabulum quickly with extreme precise. This tool and method therefore does away with the standard manual broaching techniques used for femoral preparation and the standard reaming techniques used for acetabular preparation.

[0344] An implementation of this system of a constrained ultrasonic vibration of a bone processing tool such as a rotating burr enables a three-dimensional bone-sculpting tool or a smart tool robot. The sculpting tool and smart tool robot may allow a surgeon to accurately, quickly, and safely provide non-planar contours when cutting bones as further described below while also potentially replacing all the conventional preparation tools of FIG. 52-FIG. 55.

[0345] The addition of the ultrasonic bone preparation tool to a robot makes the system a truly efficient and precise tool. The surgeon can sculpt the surfaces of the bone, for example a femur, tibia or an acetabulum and the like, and in some implementations any tissue may be sculpted with the sculpting tool, with high degree of accuracy and speed.

[0346] With current tools, it would take too much time to perform such bone preparation with a burr, making the operation extremely slow and adding risk to the patient and is therefore not performed. Some implementations include an addition of an improved bone processing tool to any haptically constrained system will make the preparation of bone for joint replacement easy, fast and efficient, ultimately delivering on the promise of a better, faster and more precise operation.

[0347] With respect to knee and shoulder replacement, some of the bone surfaces are flat which have led to prosthetic designs that have a flat undersurfaces, and the decision to prepare these bones with a saw. One concept is to add ultrasonic axial vibrations to the saw for a more effective cut. [0348] Ultrasonic enhancement may be added to all current bone removal techniques in orthopedics, including the burr, saw, reamer, and the broach, making all of these bone preparation tools more effective.

[0349] In some instances, use of the same burr described above (e.g., a rotating tool with metal-bonded diamond abrasives that is ultrasonic ally vibrated in the axial direction) to prepare surfaces of the tibia, femur and the glenoid in the shoulder for mating to an implant surface. One important benefit of use of such a burr is that the surgeon and the smart tool robot can now very quickly and effectively machine these mating surfaces any way desired, potentially introducing waves and contours that can match the undersurface of the prosthesis ( which itself has been created with waves and contours for additional stability. Portions of the tibia and the glenoid in the shoulder are flat bones that do not have inherent stability. These bones are prepared in such a way to accept a prosthesis with a flat surface. With the advent of high-power 3D bone sculpting, 3D printing, and smart tool haptic constraint, the sculpting/smart tool system may create prostheses that have waves and contours on their bottom surface to enhance stability when mated. For example, a bone surface may be 3D sculpted/contoured and a prosthesis produced to match the profile or a preformed contoured prosthesis may be provided with a non-flat profile and the mating bone surface may be sculpted/contoured to match the preformed non-flat prosthesis mating surface, particularly for the "flat ended" bone and the associated prostheses. These contouring profiles for bone and implant mating surfaces are not limited to "flat ended" bones and may have benefit in other implants or bone mating surface.

[0350] These changes can enhance the initial fixation of the prosthesis to bone by creating a contact surface areas which are more resistant to shear forces. This may provide a specific advantage for the tibial component in knee and the glenoid component in shoulder replacement surgery. These prostheses generally have flat undersurfaces and are less inherently stable. They can be made significantly more stable with the suggested changes in the method of bone preparation and prosthesis fabrication.

[0351] FIG. 56 illustrates a side view of a first set of components 5600 for a conventional bone preparation process and FIG. 57 illustrates a side view of a second set of components 5700 for a three-dimensional bone sculpting process that may be enabled by some embodiments of the present invention. [0352] Components 5600 include a bone B (e.g., a tibia) having a flat end 5605. Flat end 5605 is typically removed by a conventional (non-ultrasonic or single freedom of motion) version of saw 5200, to allow an implant 5610 to be installed. In the conventional process, bone B is prepared having a flat/planar bone mating surface 5615 which matches a flat/planar implant mating surface 5620 of implant 5610. As noted, the pair of mated surfaces may exhibit instability, especially with lateral shear loading.

[0353] Components 5700 include bone B that has been prepared differently by removing flat end 5605 using an orthopedic sculpting system as described herein. The sculpting system enables use of an implant 5705 that includes a contoured (non-flat/planar) implant mating surface 5710. A bone mating surface 5715 produced by the orthopedic sculpting system is contoured to

match/complement implant mating surface 5710. Components 5700 may include a preformed implant 5705 and surface 5715 is sculpted to match/complement for bonding, or surface 5715 is sculpted and surface 5710 is thereafter formed to match/complement surface 5715. An

additive/subtractive manufacturing process may be used to make surface 5710 and/or implant 5705. For example, implant 5705 may include two portions - a premade head portion and a later-formed body portion that may be contoured or manufactured as needed to produce surface 5710, with the head portion and body portion joined together to produce implant 5705.

[0354] Bone ingrowth technology has not enjoyed that same success in shoulder and knee replacement surgery as it has done in hip replacement surgery. One reason that this may be true is because current methods do not allow precise and uniform preparation of bone due to variable density of bone, and especially on the flat surfaces. The ultrasonic assisted bone preparation (example, the orthopedic sculpting system or smart tool robot) discussed herein has a potential to solve this problem of inconsistent bone preparation. The use of the above bone preparation method/tools instead of the standard techniques may represent a disruptive technology. The ability to quickly machine bone, and to do it in an extremely precise and safe manner may eliminate the need for bone cement in joint replacement surgery. This fact can cause an explosion in the use of porous ingrowth prosthesis/technology in orthopedics joint replacement surgery.

[0355] FIG. 58 illustrates a plan diagram of a smart tool robot 5800 which may include a type of three-dimensional bone sculpting tool. Robot 5800 includes a controller 5805 coupled to a linkage 5810 which is coupled to a high-efficiency bone preparation tool 5815, with tool 5815 including a bone processing implement 5820. Controller 5805 includes systems and methods for establishing and monitoring a three-dimensional spatial location for implement 5820. Controller 5805 further includes governance systems for linkage 5810. Collectively, controller 5805 and linkage 5810 may include a type of constraint, with other systems and methods optionally including another type of constraint and optionally providing.

[0356] Linkage 5810, illustrated as including a mechanically limited articulating arm, is coupled to both controller 5805 and tool 5815. In some cases when processing a particular in-patient bone, controller 5805 may predefine a set of bone regions of the in-patient bone for a processing (e.g., a cutting, a removing, a reaming, a sawing, a broaching, a burring, and the like). Controller 5805 may monitor a relative, or absolute, location of implement 5820 relative to a particular portion of the in-patient bone to be processed and compare that particular portion with the predefined regions. Those predefined regions may include a first subset of regions to be processed by implement 5820 and in some cases also include (or alternatively substitute for the first subset) a second subset of regions not to be processed by implement 5820. Controller 5805 provides a realtime feedback to the user regarding an appropriateness or desirability of processing each the particular portion of bone at the location of implement 5820.

[0357] In some cases, the realtime feedback may include a realtime haptic signal imparted from controller 5805 through linkage 5810 to tool 5815. That haptic signal may be of sufficient strength to significantly restrict an ability of an operator to casually move implement 5820 to a region of the in-patient bone that is not to be processed, and some cases may essentially prevent or inhibit the locating of implement 5820 to those regions of the in-patient that are not to be processed.

[0358] Other feedback signals may be included in addition, or in lieu of, the haptic system. Audio feedback may in some cases be sufficient to provide feedback to an operator.

[0359] Tool 5815 may be an embodiment of an ultrasonically enhanced bone preparation tool which operates implement 5820. Tool 5815 includes a motive system that operates implement 5820 with a bone processing motion. The bone processing motion includes a primary motion having a primary freedom of motion (e.g., for a burr as illustrated, the primary motion may include a rotation about a longitudinal axis, this primary motion having a freedom of motion that includes the rotation about the longitudinal axis). The bone processing motion includes a secondary motion having a secondary freedom of motion, the secondary freedom of motion different from the first freedom of motion. The secondary motion includes an ultrasonic vibratory motion that enhances the bone-preparation of implement 2020 than would be the case of the primary motion alone. [0360] Different implements and tools may include varying primary and secondary motions, there generally being six freedom of motion possibilities for the primary or secondary motions: x, y, and z translations and rotations about any of the x, y, and z axes. Typically the primary motion will include a repetitive (and sometimes reciprocating) component.

[0361] An operator grips tool 5815 and manipulates it by hand. Controller 5805

automatically monitors these manipulations to establish a relative location of implement 5820 with respect to a particular portion of an in-patient bone. Comparison of the relative location to predetermined/premapped regions of the in-patient bone that identify processable/non-processable regions results in controller 5820 is used to provide appropriate realtime feedback signals to the operator for each particular portion of bone. Under some circumstances, such as when greater autonomy is allowed for automated equipment implementing certain bone-processing procedures, system 5800 may be adapted to offer greater levels of autonomy up to, in some cases, automatically processing a portion of bone without substantive input from an operator.

[0362] FIG. 59-FIG. 64 illustrate a set of graphs of Force (y-axis) versus displacement (x- axis), sometimes time (T) may a secondary x-axis value. FIG. 59 illustrates a set of "cup prints" for a number of interactions between a cup and a cavity. Each combination of an implant (e.g., an acetabular cup) and its implant site (e.g., a reamed cavity in an acetabulum) has a resistive force (FR) that may be thought of as a particular cup print unique for that combination. FIG. 59 includes four such cup prints. Factors influencing the cup print include bone density (hard/soft), cup geometry (elliptical/spherical), cup surface preparation (e.g., roughness), and reaming preparation. Other sensors or sets of sensors may produce a more complex characteristic sensor print for processing of a prosthesis or portion of a prosthesis.

[0363] FIG. 60 illustrates a particular one representative cup print that relates to one cup/cavity interaction. FIG. 61 illustrates a controlled modulated installation force envelope superimposed over the cup print of FIG. 60. Typically the amplitude of the modulation increases as the implant is seated, with too great of force increasing a risk of fracture and too little force increasing a risk of poor "seatedness" - a property of the implant relating to how well seated it is within its installation site.

[0364] FIG. 62 illustrates an example installation force envelope that is representative of use of a mallet in its production. In this example, a surgeon "feels" and "listens" for the magic zone - adequate insertion and good pull-out force (seatedness) while being concerned with every strike that the installation site may fracture. A representation of a non-controlled mallet- applied installation force is shown superimposed over the cup print of FIG. 60. A strike may have poor seating and a following strike may result in a force in the fracture zone.

[0365] FIG. 63 illustrates an example installation force envelope that is representative of possible use of a BMD3 for its production. In this example, a surgeon dials into the magic zone by gradually changing the BMD3 force-applied profile. A BMD3 controlled modulated installation force envelope is shown superimposed over the cup print of FIG. 60. The surgeon is able to use a BMD3-type tool to walk the envelope (the contour of the installation force envelope) up and into the magic zone with greatly improved confidence of achieving the desired seatedness without greatly increasing a risk of fracture. Frictional forces may be decreased (effectively and realistically) at certain frequencies that may improve as the frequency increases (e.g., one to hundreds of Hertz or more, one-two kilohertz or more, and beyond to ultrasonic frequencies above two kilohertz). The reduced frictional forces may also enable easier alignment of the cup during and/or after

insertion/placement.

[0366] FIG. 64 illustrates an example installation force envelope that may be representative of possible use of a BMD4 for its production. In this example, a surgeon dials into the magic zone by dialing the BMD4 force-applied profile. A BMD4 controlled modulated installation force envelope is shown superimposed over the cup print of FIG. 60. The surgeon is able to use a BMD4-type tool to dial into the magic zone (the contour of the installation force envelope) with greatly improved confidence of achieving the desired seatedness without greatly increasing a risk of fracture and while maintaining a desired alignment/positioning, for example, within the Lewinski range. A hybrid BMD3/BMD4 embodiment may provide a hybrid controlled modulated installation force envelope that offers advantages of both BMD3 and BMD4.

[0367] FIG. 65 illustrates a representative installation gun 6500. The installation gun may be operable with operable using pneumatics, though other implementations may use other mechanisms including motors, engines, motive systems, and the like for creating a desired vibratory motion in a prosthesis to be installed.

[0368] Installation gun 6500 may be used to control precisely one or both of (i) insertion, and (ii) abduction and anteversion angles of a prosthetic component. Installation gun 6500 preferably allows both installation of an acetabular cup into an acetabulum at a desired depth and setting or adjusting an orientation of the cup for both abduction and anteversion to desired values. [0369] Installation gun 6500 may include a controller with a handle supporting an elongate tube that terminates in an adapter that engages a cup. Operation of a trigger may initiate a motion of the elongate tube. This motion is referred to herein as an installation force and/or installation motion that is much less than the impact force used in a conventional replacement process. An exterior housing allows the operator to hold and position the prosthesis (e.g., the cup) while elongate tube moves within. Some embodiments may include a handle or other grip in addition to or in lieu of the housing that allows the operator to hold and operate installation gun without interfering with the mechanism that provides a direct transfer of installation motion to the prosthesis. The illustrated embodiment may include the prosthesis held securely by adapter allowing a tilting and/or rotation of gun about any axis to be reflected in the position/orientation of the secured prosthesis.

[0370] The installation motion includes constant, cyclic, periodic, and/or random motion (amplitude and/or frequency) that allows the operator to install the cup into the desired position (depth and orientation) without application of an impact force. There may be continuous movement or oscillations in one or more of six degrees of freedom including translation(s) and/or rotation(s) of an adapter about the X, Y, Z axes (e.g., oscillating translation(s) and/or oscillating/continuous rotation(s) which could be different for different axes such as translating back and forth in the direction of the longitudinal axis of the central support while rotating continuously around the longitudinal axis). This installation motion may include continuous or intermittent very high frequency movements and oscillations of small amplitude that allow the operator to easily install the prosthetic component in the desired location, and preferably also to allow the operator to also set the desired angles for abduction and anteversion.

[0371] In some implementations, the controller includes a stored program processing system that includes a processing unit that executes instructions retrieved from memory. Those instructions could control the selection of the motion parameters autonomously to achieve desired values for depth, abduction and anteversion entered into by the surgeon or by a computer aided medical computing system such as the computer navigation system. Alternatively those instructions could be used to supplement manual operation to aid or suggest selection of the motion parameters.

[0372] For more automated systems, consistent and unvarying motion parameters are not required and it may be that a varying dynamic adjustment of the motion parameters better conform to an adjustment profile of the cup installed into the acetabulum and status of the installation. An adjustment profile is a characterization of the relative ease by which depth, abduction and anteversion angles may be adjusted in positive and negative directions. In some situations these values may not be the same and the installation gun could be enhanced to adjust for these differences. For example, a unit of force applied to pure positive anteversion may adjust anteversion in the positive direction by a first unit of distance while under the same conditions that unit of force applied to pure negative anteversion may adjust anteversion in the negative direction by a second unit of distance different from the first unit. And these differences may vary as a function of the magnitude of the actual angle(s). For example, as the anteversion increases it may be that the same unit of force results in a different responsive change in the actual distance adjusted. The adjustment profile when used helps the operator when selecting the actuators and the impact force(s) to be applied. Using a feedback system of the current real-time depth and orientation enables the adjustment profile to dynamically select/modify the motion parameters appropriately during different phases of the installation. One set of motion parameters may be used when primarily setting the depth of the implant and then another set used when the desired depth is achieved so that fine tuning of the abduction and anteversion angles is accomplished more efficiently, all without use of impact forces in setting the depth and/or angle adjustment(s).

[0373] This device better enables computer navigation as the installation/adjustment forces are reduced as compared to the impacting method. This makes the required forces more compatible with computer navigation systems used in medical procedures which do not have the capabilities or control systems in place to actually provide impacting forces for seating the prosthetic component. And without that, the computer is at best relegated to a role of providing after-the-fact assessments of the consequences of the surgeon's manual strikes of the orthopedic mallet. (Also provides information before and during the impaction. It is a problem that the very act of impaction introduces variability and error in positioning and alignment of the prosthesis.

[0374] FIG. 65 illustrates a representative installation system 6500 including a pulse transfer assembly 6505 and an oscillation engine 610; FIG. 66 illustrates a disassembly of representative installation system 6500; FIG. 6700 illustrates a first disassembly view of pulse transfer assembly 6505; and FIG 68 illustrates a second disassembly view of pulse transfer assembly 6505 of installation system 6500.

[0375] Installation system 6500 is designed for installing a prosthesis that, in turn, is configured to be implanted into a portion of bone at a desired implantation depth. The prosthesis includes some type of attachment system (e.g., one or more threaded inserts, mechanical coupler, link, or the like) allowing the prosthesis to be securely and rigidly held by an object such that a translation and/or a rotation of the object about any axis results in a direct corresponding translation and/or rotation of the secured prosthesis.

[0376] Oscillation engine 6510 includes a controller coupled to a vibratory machine that generates an original series of pulses having a generation pattern. This generation pattern defines a first duty cycle of the original series of pulses including one or more of a first pulse amplitude, a first pulse direction, a first pulse duration, and a first pulse time window. This is not to suggest that the amplitude, direction, duration, or pulse time window for each pulse of the original pulse series are uniform with respect to each other. Pulse direction may include motion having any of six degrees of freedom - translation along one or more of any axis of three orthogonal axes and/or rotation about one or more of these three axes. Oscillation engine 6510 includes an electric motor powered by energy from a battery, though other motors and energy sources may be used.

[0377] Some engines are directly coupled to the implant or prosthesis to be processed and in other cases there is a decoupling mechanism between the engine and the implant/prosthesis.

Installation tool 6500 includes a decoupled engine.

[0378] Pulse transfer assembly 6505 includes a proximal end 6515 coupled to oscillation engine 6510 and a distal end 6520, spaced from proximal end 6520, coupled to the prosthesis using a connector system 6525. Pulse transfer assembly 6505 receives the original series of pulses from oscillation engine 6510 and produces, responsive to the original series of pulses, an installation series of pulses having an installation pattern. Similar to the generation pattern, the installation pattern defines a second duty cycle of the installation series of pulses including a second pulse amplitude, a second pulse direction, a second pulse duration, and a second pulse time window.

Again, this is not to suggest that the amplitude, direction, duration, or pulse time window for each pulse of the installation pulse series are uniform with respect to each other, nor does it imply that they are non-uniform. Pulse direction may include motion having any of six degrees of freedom - translation along one or more of any axis of three orthogonal axes and/or rotation about one or more of these three axes.

[0379] For some embodiments of pulse transfer assembly 6505, the installation series of pulses will be strongly linked to the original series and there will be a close match, if not identical match, between the two series (e.g., directly coupled and not decoupled implementations). Some embodiments may include a more complex pulse transfer assembly 6505 that produces an installation series that is somewhat different, or very different, from the original series.

[0380] Connector system 6525 (e.g., one or more threaded studs complementary to the threaded inserts of the prosthesis, or other complementary mechanical coupling system) is disposed at proximal end 6520. Connector system 6525 is configured to secure and rigidly hold the prosthesis. In this way, the attached prosthesis becomes a secured prosthesis when engaged with connector system 6525.

[0381] Pulse transfer assembly 6505 communicates the installation series of pulses to the secured prosthesis and produces an applied series of pulses that are responsive to the installation series of pulses. Similar to the generation pattern and the installation pattern, the applied pattern defines a third duty cycle of the applied series of pulses including a third pulse amplitude, a third pulse direction, a third pulse duration, and a third pulse time window. Again, this is not to suggest that the amplitude, direction, duration, or pulse time window for each pulse of the applied pulse series are uniform with respect to each other. Pulse direction may include motion having any of six degrees of freedom - translation along one or more of any axis of three orthogonal axes and/or rotation about one or more of these three axes.

[0382] For some embodiments of pulse transfer assembly 6505, the applied series of pulses will be strongly linked to the original series and/or the installation series and there will be a close, if not identical, match between the series. Some embodiments may include a more complex pulse transfer assembly 6505 that produces an applied series that is somewhat different, or very different, from the original series and/or the installation series. In some embodiments, for example one or more components may be integrated together (for example, integrating oscillation engine 6510 with pulse transfer assembly 6505) so that the first series and the second series, if they exist

independently are nearly identical if not identical).

[0383] The applied series of pulses are designed to impart a vibratory motion to the secured prosthesis that enable an installation of the secured prosthesis into the portion of bone to within 95% of the desired implantation depth without a manual impact. That is, in operation, the original pulses from oscillation engine 6510 propagate through pulse transfer assembly 6505 (with implementation- depending varying levels of fidelity) to produce the vibratory motion to the prosthesis secured to connector system 6525. In a first implementation, the vibratory motion allows implanting without manual impacts on the prosthesis and in a second mode an orientation of the implanted secured prosthesis may be adjusted by rotations of installation system 6500 while the vibratory motion is active, also without manual impact. In some implementations, the pulse generation may produce different vibratory motions optimized for these different modes.

[0384] Installation system 6500 includes an optional sensor 6530 (e.g., a flex sensor or the like) to provide a measurement (e.g., quantitative and/or qualitative) of the installation pulse pattern communicated by pulse transfer assembly 6505. This measurement may be used as part of a manual or computerized feedback system to aid in installation of a prosthesis. For example, in some implementations, the desired applied pulse pattern of the applied series of pulses (e.g., the vibrational motion of the prosthesis) may be a function of a particular installation pulse pattern, which can be measured and set through sensor 6530. In addition to, or alternatively, other sensors may aid the surgeon or an automated installation system operating installation system 6500, such as a bone density sensor or other mechanism to characterize the bone receiving the prosthesis to establish a desired applied pulse pattern for optimal installation. In some implementations, sensor 6530 measures force magnitude as part of the installation pulse pattern.

[0385] The disassembled views of FIG. 67 and FIG. 68 detail a particular implementation of pulse transfer assembly 6505, it being understood that there are many possible ways of creating and communicating an applied pulse pattern responsive to a series of generation pulses from an oscillation engine. The illustrated structure of FIG. 67 and FIG. 68 generate primarily

longitudinal/axial pulses in response to primarily longitudinal/axial generation pulses from oscillation engine 6510.

[0386] Pulse transfer assembly 6505 includes an outer housing 6535 containing an upper transfer assembly 6740, a lower transfer assembly 6745 and a central assembly 6750. Central assembly 6750 includes a double anvil 6755 that couples upper transfer assembly 6740 to lower transfer assembly 6745. Outer housing 6735 and central assembly 6750 each include a port allowing sensor 6730 to be inserted into central assembly 6750 between an end of double anvil 6755 and one of the upper/lower transfer assemblies.

[0387] Upper transfer assembly 6740 and lower transfer assembly 6745 each include a support 6760 coupled to outer housing 6535 by a pair of connectors. A transfer rod 6765 is moveably disposed through an axial aperture in each support 6760, with each transfer rod 6765 including a head at one end configured to strike an end of double anvil 6755 and a coupling structure at a second end. A compression spring 6770 is disposed on each transfer rod 6765 between support 6760 and the head. The coupling structure of upper transfer assembly 6740 cooperates with oscillation engine 6710 to receive the generated pulse series. The coupling structure of lower transfer assembly 6745 includes connector system 6525 for securing the prosthesis. Some embodiments may include an adapter, not shown, that adapts connector system 6525 to a particular prosthesis, different adapters allowing use of pulse transfer assembly 6505 with different prosthesis.

[0388] Central assembly 6750 includes a support 6775 coupled to outer housing 6535 by a connector and receives double anvil 6755 which moves freely within support 6775. The heads of the upper transfer assembly and the lower transfer assembly are disposed within support 6775 and arranged to strike corresponding ends of double anvil 6755 during pulse generation.

[0389] In operation, oscillation engine 6510 generates pulses that are transferred via pulse transfer assembly 6505 to the prosthesis secured by connector system 6525. The pulse transfer assembly 6505, via upper transfer assembly 6740, receives the generated pulses using transfer rod 6765. Transfer rod 6765 of upper transfer assembly 6740 moves within support 6760 of upper transfer assembly 6740 to communicate pulses to double anvil 6755 moving within support 6775. Double anvil 6755, in turn, communicates pulses to transfer rod 6765 of lower transfer assembly 6745 to produce vibratory motion of a prosthesis secured to connector system 6525. Transfer rods 6765 move, in this illustrated embodiment, primarily longitudinally/axially within outer housing 6535 (a longitudinal axis defined as extending between proximate end 6515 and distal end 6520. In this way, the surgeon may use outer housing 6535 as a hand hold when installing and/or positioning the vibrating prosthesis.

[0390] The use of discrete transfer portions (e.g., upper, central, and lower transfer assemblies) for pulse transfer assembly 6505 may allow a form of loose coupling between oscillation engine 6510 and a secured prosthesis. In this way pulses from oscillation engine 6510 are converted into a vibratory motion of the prosthesis as it is urged into the bone during operation. Some embodiments may provide a stronger coupling by directly securing one component to another, or substituting a single component for a pair of components.

[0391] The embodiment of FIG. 65 has demonstrated insertion of a prosthetic cup into a bone substitute substrate with ease and a greatly reduced force as compared to use of a mallet and tamp, especially as no impaction was required. While the insertion was taking place and vibrational motion was present at the prosthesis, the prosthesis could be positioned with relative ease by torqueing on a handle/outer housing to an exact desired alignment/position. The insertion force is variable and ranges between 20 to 800 pounds of force. Importantly the potential for use of significantly smaller forces in application of the prosthesis (in this case the acetabular prosthesis) in bone substrate with the present invention is demonstrated to be achievable.

[0392] Installation system 6500 may include an oscillation engine producing pulses at approximately 60 Hz. System 6500 operated at 60 Hz. In testing, approximately 4 seconds of operation resulted in a desired insertion and alignment of the prosthesis (meaning about 240 cycles of the oscillation engine). Conventional surgery using a mallet striking a tamp to impact the cup into place is generally complete after 10 blows of the mallet/hammer.

[0393] Experimental

[0394] System 6500 was tested in a bone substitute substrate with a standard Zimmer acetabular cup using standard technique of under reaming a prepared surface by 1 mm and inserting a cup that was one millimeter larger. The substrate was chosen as the best option available to study this concept, namely a dense foam material. It was recognized that certain properties of bone would not be represented here (e.g. less of an ability of the bone substrate to stretch before failure).

[0395] FIG. 65 demonstrated easy insertion and positioning of the prosthetic cup within the chosen substrate. Some embodiments were able to move the cup in the substrate with relative ease. There was no requirement for a mallet or hammer for application of a large impact. These experiments demonstrated that the prosthetic cups could be inserted in bone substitute substrates with significantly less force and more control than what could be done with blows of a hammer or mallet. It is possible that the same phenomena can be reproduced in human bone. Some

embodiments may provide that the prosthetic cup may be inserted with ease using very little force.

[0396] Additionally some embodiments may provide that simultaneously, while the cup is being inserted, the position of the cup can be adjusted under direct visualization with any intraoperative measurement system (navigation, fluoroscopy, etc.). This invention provides a system that allows insertion of a prosthetic component with NON-traumatic force (insertion) as opposed to traumatic force (impaction).

[0397] Experimental configuration - System 6500 [0398] Oscillation engine 6510 included a Craftsman GO Hammerhead nailer used to drive fairly large framing nails into wood in confined spaces by applying a series of small impacts very rapidly in contrast to application of few large impacts.

[0399] The bone substitute was 15 pound density urethane foam to represent the pelvic acetabulum. It was shaped with a standard cutting tool commonly used to clean up a patient's damaged acetabulum. A 54 mm cup and a 53 mm cutter were used in testing.

[0400] In one test, the cup was inserted using a mallet and tamp, with impaction complete after 7 strikes. Re-orientation of the cup was required by further strikes on a periphery of the cup after impaction to achieve a desired orientation. It was qualitatively determined that the feel and insertion were consistent with impaction into bone.

[0401] An embodiment of system 6500 was used in lieu of the mallet and tamp method. Several insertions were performed, with the insertions found to be much more gradual; allowing the cup to be guided into position (depth and orientation during insertion). Final corrective positioning is easily achievable using lateral hand pressure to rotate the cup within the substrate while power was applied to the oscillation engine.

[0402] Further testing using the sensor included general static load detection done to determine the static (non-impact) load to push the cup into the prepared socket model. This provided a baseline for comparison to the impact load testing. The prosthesis was provided above a prepared socket with a screw mounted to the cup to transmit a force applied from a bench vise. The handle of the vice was turned to apply an even force to compress the cup into the socket until the cup was fully seated. The cup began to move into the socket at about an insertion force of -200 pounds and gradually increased as diameter of cup inserted into socket increased to a maximum of 375 pounds which remained constant until the cup was fully seated.

[0403] Installation system 6500 was next used to install the cup into a similarly prepared socket. Five tests were done, using different frame rates and setup procedures, to determine how to get the most meaningful results. All tests used a 54 mm acetabular Cup. The oscillation engine ran at an indicated 60 impacts/second. The first two tests were done at 2,000 frames/second, which wasn't fast enough to capture all the impact events, but helped with designing the proper setup. Test 3 used the oscillation engine in an already used socket, 4,000 frames per second. Test 4 used the oscillation engine in an unused foam socket at 53 mm, 4,000 frames per second. [0404] Test 3: In already compacted socket, the cup was pulsed using the oscillation engine and the pulse transfer assembly. Recorded strikes between 500 and 800 lbs., with an average recorded pulse duration 0.8 Ms.

[0405] Test 4: Into an unused 53 mm socket, the cup was pulsed using the oscillation engine and the pulse transfer assembly. Recorded impacts between 250 and 800 lbs., and an average recorded pulse duration 0.8 Ms. Insertion completed in 3.37 seconds, 202 impact hits.

[0406] Test 5: Into an unused 53 mm socket, the cup was inserted with standard hammer (for reference). Recorded impacts between 500 and 800 lbs., and an average recorded pulse duration 22.0 Ms. Insertion completed in 4 seconds using 10 impact hits for a total pressure time of 220 Ms. This test was performed rapidly to complete it in 5 seconds for good comparability with tests 3 and 4 used 240 hits in 4 seconds, with a single hit duration of 0.8 MS, for a total pressure time of 192 Ms.

[0407] Additionally, basic studies can further be conducted to correlate a density and a porosity of bone at various ages (e.g., through a cadaver study) with an appropriate force range and vibratory motion pattern required to insert a cup using the present invention. For example a surgeon will be able to insert sensing equipment in patient bone, or use other evaluative procedures,

(preoperative planning or while performing the procedure for example) to asses porosity and density of bone. Once known, the density or other bone characteristic is used to set an appropriate vibratory pattern including a force range on an installation system, and thus use a minimal required force to insert and/or position the prosthesis.

[0408] BMD is a "must have" device for all medical device companies and surgeons.

Without BMD the Implantation problem is not addressed, regardless of the recent advances in technologies in hip replacement surgery (i.e.; Navigation, Fluoroscopy, MAKE/robotics, accelerometers/gyro meters, etc.). Acetabular component (cup) positioning remains the biggest problem in hip replacement surgery. Implantation is the final step where error is introduced into the system and heretofore no attention has been brought to this problem. Current technologies have brought significant awareness to the position of the implants within the pelvis during surgery, prior to impaction. However, these techniques do not assist in the final step of implantation.

[0409] BMD allows all real time information technologies to utilize (a tool) to precisely and accurately implant the acetabular component (cup) within the pelvic acetabulum. BMD device coupled with use of navigation technology and fluoroscopy and (other novel measuring devices) is the only device that will allow surgeons from all walks of life, (low volume/high volume) to perform a perfect hip replacement with respect to acetabular component (cup) placement. With the use of BMD, surgeons can feel confident that they are doing a good job with acetabular component positioning, achieving the "perfect cup" every time. Hence the BMD concept eliminates the most common cause of complications in hip replacement surgery which has forever plagued the surgeon, the patients and the society in general.

[0410] There may be use of ultrasound devices in connection with some aspects of THR, primarily for implant removal (as some components may be installed using a cement that may be softened using ultrasound energy). There may be some suggestion that some ultrasonic devices that employ "ultrasound" energy could be used to insert a prosthesis for final fit, but it is in the context of a femoral component and it is believed that these devices are not presently actually used in the process). Some embodiments of BMD, in contrast, can simply be a vibratory device (non ultrasonic, others ultrasonic, and some hybrid impactful and vibratory), and is more profound than simply an implantation device as it is most preferably a positioning device for the acetabular component in THR. Further, there is a discussion that ultrasound devices may be used to prepare bones for implanting a prosthesis. BMD may address preparation of the bone in some aspects of the present invention.

[0411] Some embodiments BMD include devices that concern themselves with proper installation and positioning of the prosthesis (e.g., an acetabular component) at the time of implanting of the prosthesis. Very specifically, it uses some form of vibratory energy coupled with a variety of "real time measurement systems" to POSITION the cup in a perfect alignment with minimal use of force. A prosthesis, such as for example, an acetabular cup, resists insertion. Once inserted, the cup resists changes to the inserted orientation. The BMDs of the present invention produce an insertion vibratory motion of a secured prosthesis that reduces the forces resisting insertion. In some implementations, the BMD may produce a positioning vibratory motion that reduces the forces resisting changes to the orientation. There are some implementations that produce both types of motion, either as a single vibratory profile or alternative profiles. In the present context for purposes of the present invention, the vibratory motion is characterized as "floating" the prosthesis as the prosthesis can become much simpler to insert and/or re-orient while the desired vibratory motion is available to the prosthesis. Some embodiments are described as producing vibrating prosthesis with a predetermined vibration pattern. In some implementations, the predetermined vibration pattern is predictable and largely completely defined in advance. In other implementations, the predetermined vibration pattern includes randomized vibratory motion in one or more motion freedoms of the available degrees of freedom (up to six degrees of freedom). That is, whichever translation or rotational freedom of motion is defined for the vibrating prosthesis, any of them may have an intentional randomness component, varying from large to small. In some cases the randomness component in any particular motion may be large and in some cases predominate the motion. In other cases the randomness component may be relatively small as to be barely detectable.

[0412] A tool, among others, that may support the force measurement includes an axially- impactful Behzadi Medical Device (BMD4), such as embodiment 500 illustrated in FIG. 5. The BMD4 may include a moveable hammer sliding axially and freely along a rod. The rod may include a proximal stop and a distal stop. These stops that may be integrated into rod allow transference of force to rod when the hammer strikes the distal stop. At a distal end of the rod, the device includes an attachment system for a prosthesis. For example, when the prosthesis includes an acetabular cup having a threaded cavity, the attachment system may include a complementary threaded structure that screws into the threaded cavity. The illustrated design of the device allows only a perfect axial force to be imparted. The surgeon cannot deliver a blow to the edge of an impaction plate. Therefore the design of this instrument is in and of itself protective, eliminating a problem of "surgeon's mallet hitting on the edge of the impaction plate" or other mis-aligned force transference, and creating undesirable torques, and hence unintentional mal-alignment of the prosthesis from an intended position/orientation. This embodiment may be modified to include a vibratory engine as described herein.

[0413] The embodiment may include a pressure sensor to provide feedback during installation. With respect to management of the vibration/force required for some of these tasks, it is noted that with current techniques (the use of the mallet) the surgeon has no indication of how much force is being imparted onto the implant and/or the implant site (e.g., the pelvis). Laboratory tests may be done to estimate what range of force should be utilized in certain age groups (as a rough guide) and then fashioning a device 1100, for example a modified sledgehammer or a cockup gun to produce just the right amount of force and/or producing a predetermined force of a known magnitude. Typically the surgeon may use up to 2000N to 3000N of force to impact a cup into the acetabular cavity. Also, since some embodiments cannot deliver the force in an incremental fashion as described in association with the BMD3 device, the device may include a stopgap mechanism. Some embodiments of the BMD3 device have already described the application of a sensor in the body of the impaction rod. The device may include a sensing system/assembly embedded in the device, for example proximate the rod near the distal end, and used to provide valuable feedback information to the surgeon. The pressure sensor can let the surgeon know when the pressures seem to have maximized, whether used for the insertion of an acetabular cup, or any other implant including knee and shoulder implants and rods used to fix tibia and femur fractures. When the pressure sensor is not showing an advance or increase in pressure readings and has plateaued, the surgeon may determine it is time to stop operation/impacting. An indicator, for example an alarm can go off or a red signal can show when maximal peak forces are repeatedly achieved. As noted above, the incorporated patents describe a presence of a pressure sensor in an installation device, the presence of which was designed as part of a system to characterize an installation pulse pattern communicated by a pulse transfer assembly. The disclosure here relates to a pressure sensor provided not to characterize the installation vibration/pulse pattern but to provide an in situ feedback mechanism to the surgeon as to a status of the installation, such as to reduce a risk of fracturing the installation site. Some embodiments may also employ this pressure sensor for multiple purposes including characterization of an applied pulse pattern such as, for example, when the device includes automated control of an impacting engine coupled to the hammer. Other embodiments of this invention may dispose the sensor or sensor reading system within a handle or housing of the device rather than in the central rod or shaft.

[0414] Previous work have sought to address the two problems noted above culminating in a series of devices identified as BMD2, BMD3, and BMD4. Each of these systems attempts to address the two problems noted above with different and novel methods.

[0415] The BMD2 concept proposed a system of correcting a cup (acetabular implant) that had already been implanted in a mis-aligned position. It basically involves a gun like tool with a central shaft and peripheral actuators, which attaches to an already implanted cup with the use of an adaptor. Using computer navigation, through a series of calculations, pure points (specifically defined) and secondary points on the edge of the cup are determined. This process confers positional information to the edge of the cup. The BMD2 tool has actuators that correspond to these points on the cup, and through a computer program, the appropriate actuators impact on specific points on the edge of the cup to adjust the position of the implanted cup. The surgeon dials in the desired alignment and the BMD2 tool fires the appropriate actuators to realign the cup to the perfect position. [0416] In BMD3, some embodiments may apply vibratory forces in a manner to disarm frictional forces in insertion of the acetabular cup into the pelvis. The following questions may aid in defining one or more embodiments: Is it possible to insert and position the cup into the pelvis without high energy impacts? Is it possible to insert the cup using vibratory energy? Is insertion and simultaneous alignment and positioning of the cup into the pelvis possible? BMD3 prototypes were designed and the concept of vibratory insertion was proven. It was possible to insert the cup with vibratory energy. The BMD3 principle involved the breaking down of the large momentum associated with the discrete blows of the mallet into a series of small taps, which in turn did much of the same work incrementally, and in a stepwise fashion. Some embodiments may allow that this method provides modulation of force required for cup insertion. In determining an amount of force to be applied, the resistive forces involved in a cup/cavity interaction were studied. It was determined that there are several factors that produce the resistive force to cup insertion. These include bone density (hard or soft), cup geometry (spherical or elliptical), and surface roughness of the cup. With the use of BMD3 vibratory insertion, some embodiments may demonstrate through FEM studies, that the acetabulum experiences less stress and deformation and the cup experiences a significantly smoother sinking pattern. Some embodiments may discover an added benefit of ease of movement and an ability to align the cup with the BMD3 vibratory tool. During high frequency vibration the frictional forces are disarmed in both effective and realistic ways, (see discussion herein and in the incorporated applications - periodic static friction regime, kinetic friction regime). Some embodiments may allow that certain "mode shapes" (preferred directions of deformation) can be elicited with high frequency vibration to allow easy insertion and alignment of the cup. The pelvis has a resonant frequency and is a viscoelastic structure. Theoretically, vibrations can exploit the elastic nature of bone and its dynamic response. This aspect of vibratory insertion can be used to advantage in cup insertion and deserves further consideration. Empirically, the high frequency aspect of BMD3 allows easy and effortless movement and insertion of the cup into the pelvis. This aspect BMD3 is clinically significant allowing the surgeon to align the cup in perfect position while the vibrations are occurring.

[0417] The BMD4 idea was described to address the two initial problems (uncontrolled force and undesirable torques) in a simpler manner. The undesirable torque and mis-alignment problem from mallet blows were neutralized with the concept of the "slide-hammer" which only allows axial exertion of force. With respect to the amount of force, BMD4 allowed the breaking down of the large impaction forces (associated with the use of the mallet) into quantifiable and smaller packets of force. The delivery of this force occurs through a simple slide-hammer, cockup gun, robotic tool, electric or pneumatic gun (all of which deliver a sliding mass over a central coaxial shaft attached to the impaction rod and cup. In the BMD4 discussions, some embodiments described two "stop gap" mechanisms to protect the pelvis from over exertion of force. An embodiment may include a pressure sensor in the shaft of the BMD4 tool that monitors the force pressure in the (tool/cup system). This force sensor would determine when the pressure had plateaued indicating the appropriate time to stop the manual impacts. Some embodiments may also include a pitch/sound sensor in the room, attached to the gun or attached to the pelvis that would assess when the pitch is not advancing, alerting the surgeon to stop applying force. These four aspects of BMD4 (coaxially of the gun, quantification and control of the force, a force sensor, a sound sensor) are separated and independent functions which can could be used alone or in conjunction with each other.

[0418] Some embodiments may include utilization of BMD4's (coaxiality and force control function) and BMD3's (vibratory insertion) for application of femoral and humeral heads to trunnions, to solve the trunnionosis problem.

[0419] Materials and Methods: During development of some embodiments, different aspects of the BMD3 and BMD4 prototypes were evaluated. With BMD3 concept some embodiments may seek to study several aspects of vibratory insertion:

[0420] 1. The ultimate effect of frequency on cup insertion.

[0421] 2. The range of impact forces achievable with vibratory insertion.

[0422] 3. The effect of frequency and vibratory impaction forces on cup insertion and (extraction forces measured to assess the quality of insertion).

[0423] With Respect to BMD4 various aspects of "controlled impaction" utilizing Drop Tests (dynamic testing) and Instron Machine (static testing) to determine the behavior of cup/cavity interaction were studied.

[0424] Results: BMD3

[0425] Preliminary results suggest that vibratory insertion of the cup into a bone substitute is possible. It is clear that vibratory insertion at higher frequencies allow easy insertion and alignment of the cup in bone. [0426] It is unclear as to how much higher frequencies contribute to the depth and quality of insertion, as measured by the extraction force, particularly as the cup is inserted deeper into the substrate.

[0427] Some embodiments may determine that with vibrational insertion, the magnitude of impaction force is limited and dependent on other mechanical factors such as frequency of vibration and the dwell time. So far 400 lbs. of force has been achieved with the BMD/BE prototype, 250 lbs. of force have been achieved with the auto hammer prototype, and 150 lbs. of force have been achieved by the pneumatic prototype. Further work is underway to determine an upper limit of achievable forces with the Vibrational tools.

[0428] During a study of Vibrational insertion it was also discovered that vibrational insertion can be unidirectional or bidirectional. For insertion of the cup into a substrate it was illustrated that unidirectional vibratory insertion (in a positive direction) may be ideal. It was discovered that unidirectional vibratory withdrawal and bidirectional vibration have other applications such as in revision surgery, preparation of bone, and for insertion of bidirectional prosthetic cups. The directionality of the BMD3 vibratory prototype and its applications will be further discussed in additional applications.

[0429] Results: BMD4

[0430] With respect to controlled impacts some embodiments may seek to understand the cup/cavity interaction in a more comprehensive way. Some embodiments may help discover a nature of the resistive forces involved in a cup/cavity interaction. In some cases it may be necessary or desirable to understand this information in order to be able to produce an appropriate amount of force for both BMD3 "vibratory insertion" and BMD4 "controlled impaction". Some dynamic drop tests were proposed and conducted and static Instron tests were conducted to evaluate a relationship between the cup and the cavity. The drop tests were conducted using a Zimmer continuum 62mm cup and 20 lbs. urethane foam. Multiple drop tests were conducted at various impaction forces to evaluate the relationship between applied force (TMIF) and displacement of the cup, and the quality of insertion (Extraction Force). It was discovered that for insertion of a cup into a cavity the total resistive force can be generally represented by an exponential curve. Some embodiments may identify this resistive force the FR, which may be determined by measuring a relationship of applied force (TMIF) and cup insertion for any particular (cup/cavity) system. FR is a function of several factors including the spring like quality of bone which applies a compressive resistive force (Hooke' s law F=kx) to the cup, the surface roughness' s of the cup, and the geometry of the cup (e.g., elliptical versus spherical outer surface profile).

[0431] Definitions: FR = Force Resistance (total resistive force to cup insertion over full insertion of the cup into bone substitute); TMIF = Theoretical Maximum Impact Force (external force applied to the system) to accomplish cup insertion; and mIF = measured Impact Force (force measured within the system) (as measured on the BMD3 and BMD4) tools.

[0432] BMD/BE vibratory prototype

[0433] Auto hammer vibratory prototype

[0434] Pneumatic vibratory prototype

[0435] Evaluation of the drop test data reveals a nonlinear (exponential) curve that represents FR. Some embodiments may contemplate that the cup/cavity system used (62m Continum cup and 20 lb. urethane foam) have a specific profile or "cup print", and that this profile may be important to know in advance so that application of force can be done intelligently.

[0436] The general shape of FR may be observed to be non-linear with three distinct segments to the curve, parsed into sections A, B, and C. In section A the resistive force is low (from 100 to 350 lbs.) with a smaller slope. In section A, when an applied force (TMIF) greater than this FR is applied, it can produce up to 55% cup insertion and 30% extraction force. A TMIF that is tuned to cross FR at the A range is at risk for poor seating and pull out. In section B the resistive forces range from 5001bs to 9001bs. The slope rises rapidly and is significantly larger than in section A (as expected in an exponential curve). In section B, if a TMIF greater than this FR is applied, it can produce between 74% to 90% cup insertion and between 51% to 88% extraction force. This section B is sometimes referred to as the "B cloud", to signify that the applied force (TMIF) should generally be tuned to this level to obtain appropriate insertion with less risk for fracture and or pull out, regardless of whether the TMIF is applied by a BMD3 or BMD4 tool. In section C the curve asymptotes, with small incremental increase in cup insertion and large increases in extraction force. The clinical value of the higher extraction force is uncertain with increased risk of fracture. A TMIF that is tuned to cross the FR at the C range is high risk for fracture and injury to the pelvis.

[0437] FIG. 69 relates to a Behzadi Medical Device (BMDX) which may combine vibratory and axial impactful forces from BMD3 and BMD4 among other options; and FIG. 69 illustrates a Force Resistance (FR) curve for various experimental configurations, for example, force as a function of distance or displacement.

[0438] Discussion:

[0439] The FR curve represents a very important piece of information. To the surgeon the FR curve should have the same significance that a topographical map has to a mountaineer.

Knowing the resistive forces involved in any particular cup/cavity interaction is desirable in order to know how much force is necessary for insertion of the cup. Some embodiments may be improved by in vitro studies and qualifications of all cup/cavity interactions. For example it may be important to know when the same 62 mm Continum cup used in one instance is going to be used in a 40 year old or 70 year old person. The variables that will determine FR include bone density which determines the spring like quality of bone that provides compression to the cup, the geometry of the cup, an amount of under reaming, and the surface roughness of the cup. Once the FR for a particular cup and bone density is known, the surgeon is now armed with information he/she can use to reliably insert the cup. This would seem to be a much better way to approach cup insertion than banging clueless on an impaction rod with a 41bs mallet. Approaching FR with an eye for the B range will assure that the cup is not going to be poorly seated with risk of pullout or too deeply seated with a risk of fracture.

[0440] Some embodiments may approach FR with both vibratory (BMD3) insertion and controlled (BMD4 impaction) among other devices. Each of these systems has advantages and disadvantages that continue to be studied and further developed.

[0441] For example it may be the case that vibratory insertion with the current BMD3 prototypes has a clear advantage of allowing the surgeon ease of movement and insertion. The surgeon appears to be able to move the cup within the cavity by simple hand pressure to the desired alignment. This provides the appearance of a frictionless state. However, some embodiments may not be able to achieve higher forces with a BMD3 tool configuration. Some embodiments have been able to achieve up to 150 lb. (pneumatic), 250 (auto hammer), and 400 lb. (BMD/BE) in some vibratory prototypes. This level of applied force provides submaximal level of insertion and pull out force. Some embodiments may be able to achieve higher forces with the vibratory BMD3 tools (500 to 9001b s) which may provide for deeper and more secure seating. [0442] With regards to this concern, some embodiments have contemplated a novel approach to address any technological deficits. Some embodiments may include a combination of BMD3 vibratory insertion with controlled BMD4 impaction. The BMD3 vibratory tool (currently at 100 lbs. to 4001bs) is used to initiate the first phase of insertion allowing the surgeon to easily align and partially insert the prosthesis with hand pressure, while monitoring the alignment with the method of choice (A-frame, navigation, C-arm, IMU). The BMD4 controlled impaction is then utilized to apply quantifiable packets of force (100 lbs. to 9001bs) to the cup to finish the seating of the prosthesis in the B range of the FR curve. This can be done either as a single step fashion or "walking up the FR curve" fashion.

[0443] Alternatively, BMD4 controlled impaction can be utilized to insert the cup without the advantage of BMD3 tool. The BMD4 technique provides the ability to quantify and control the amount of applied force (TMIF) and provides coaxiality to avoid undesirable torques during the impaction. It is particularly appealing for robotic insertion where the position of the impaction rod is rigidly secured by the robot.

[0444] Some embodiments may provide that the BMD4 controlled impaction be utilized in two separate techniques.

[0445] The first technique involves setting the impaction force within the middle of the B Cloud where 74% to 90% insertion and 51% to 88% extraction forces could be expected, and then impacting the cup. The BMD4 tool acts through the slide hammer mechanism to produce a specific amount of force (for example 6001bs) and delivers it axially. This can be considered a single step mechanism for use of BMD4 technique.

[0446] The second method involves "walking the forces" up the FR curve. In this system the applied force (TMIF) is provided in "packets of energy". For example, the BMD4 gun may create lOOlbs packets of force. It has an internal pressure sensing mechanism that allows the tool to know if insertion is occurring or not. A force sensor and a corresponding algorithm within the BMD4 tool is described herein. The force sensor monitors the measured impact force (mIF) and the

corresponding change in mIF within the system. When impacts are applied to an "inelastic" system, energy may be lost at the interface as insertion occurs and heat is produced. This loss of energy is measured and calculated in the (change) or slope of mIF. Consecutive mIF s have to be measured and compared to previous mIFs to determine if insertion is occurring. As long as insertion is occurring impactions will continue. When the change in mIF approaches zero, insertion is not occurring, there is no dissipation of energy within the system and the slope or (change) in mIF has approached zero. At this point the cup and cavity move together as a rigid system (elastic), and all the kinetic energy of TMIF is experienced by the cup/ cavity system and mIF is measured to be the same as TMIF. When insertion is not occurring mIF has approached TMIF and change in mIF has approached zero.

[0447] At this point the next step is taken and TMIF is increased, for example by a packet of lOOlbs. The subsequent mIF measurements are taken and if the slope (change) in mIF is high, insertion is occurring with the new TMIF, therefore impacts should continue until the change in mIF approaches zero again.

[0448] Conversely, when an increase in TMIF results in an increase in mIF but not the change (slope) in mIF, an embodiment may determine that the cup is no longer inserting and has reached its maximum insertion point. When the cup stops inserting, this also the point where FR exceeds TMIF. In this manner, an algorithm has been contemplated that allows for monitoring of the forces experienced in the system. Based on this algorithm, a system is created in which the surgeon can walk the TMIF up the FR curve while being given real time feedback information as to when to stop impaction.

[0449] A general idea is that at some point in time the cup will no longer insert (even though not fully seated). This algorithm determines when no further insertion is occurring. The surgeon will be content to stop impaction in the B cloud range of the FR curve.

[0450] In some embodiments, mIF may be related to TMIF+ FR. The value of TMIF is known. The value of mIF is measured. The FR can be calculated live during insertion by the BMD3 and BMD4 tools and shown to the surgeon as a % or (probability of fracture). This calculation and algorithm could be very significant.

[0451] A few words on Alignment:

[0452] Some embodiments may provide that the BMD3 vibratory tool be used to insert the cup under monitoring by current alignment techniques (navigation, Fluoroscopy, A-frame). An embodiment may include a mechanism that could be the most efficacious method of monitoring and assuring alignment. This system may use Radlink (Xrays) and PSI (patient specific models) to set and calibrate the OR space as the first step. [0453] As a second step, it utilizes a novel technique with use of IMU technology to monitor the movement of the reamers, tools (BMDs) and impaction rods. This is discussed in a separate paper. Needs to be written up.

[0454] Summary and Recommendations for BMD/BE project.

[0455] 1. A novel system of inserting and aligning the acetabular cup in the human pelvic bone has been implemented by some embodiments. This technique involves combining aspects of the BMD3 and BMD4 prototypes, initially utilizing BMD3 vibratory insertion to partially insert and perfectly align the acetabular cup into the pelvis. Subsequently switching to the BMD4 controlled impaction technique to apply specific quantifiable forces for full seating and insertion. In this manner some embodiments may combine the proven advantages of the vibratory insertion prototype with the advantages of the controlled impaction prototype.

[0456] 2. Some embodiments may include a force sensing system within the BMD tool with capacity to measure the force experienced by the system (mIF) and calculate the change in mIF with respect to time or number of impacts. This system provides a feedback mechanism for the BMD tools as to when impaction should stop.

[0457] 3. Some embodiments may define, utilize, and/or characterize, the FR curve which is a profile (cup print) of any cup/cavity interaction. It may be the case that this "cup print" for most cup/cavity interactions may be determined in vitro to arm the surgeon with information necessary for cup insertion. There may be advantages to studying every cup/cavity interaction to determine its FR profile. Once the FR is known, BMD3 and BMD4 tools can be used to intelligently and confidently apply force for insertion of the acetabular prosthesis.

[0458] 4. Some embodiments may include two methods for use of BMD4 controlled cup impaction, including a) setting the TMIF to the middle of the B cloud (somewhere between 500 to 900 range for an FR) and producing a single stage impaction, and b) producing sequential packets of increasing TMIF in order to walk TMIF up the FR curve. (Increasing packets of lOOlbs or 2001bs)

[0459] 5. Some embodiments may implement, or take advantage, that mIF may be related to TMIF+ FR. The value of TMIF is known. The value of mIF is measured. The FR can be calculated live during insertion by the BMD3 and BMD4 tools and shown to the surgeon as a % or (probability of fracture). This calculation and algorithm could be very significant in help the surgeon to insert the cup deeply without fracture.

[0460] Concept 5W and 1H:

[0461] 1. Who: The surgeon; 2. What: Cup insertion; 3. When: When to increase the force and when to stop; 4. Where: PSI and Radlink to set and EVIU to monitor alignment and position; 5. Why: Consistency for the surgeon and the patient; and 6. How: FR for every cup/cavity interaction, BMD3 and BMD4 tools.

[0462] FIG. 70-FIG. 71 illustrate a general force measurement system 7000 for

understanding an installation of a prosthesis P into an installation site S of a bone B (e.g., an acetabular cup into an acetabulum during total hip replacement procedures on a live patient); FIG. 70 illustrates an initial engagement of prosthesis P to a cavity at installation site S when prosthesis P is secured to a force sensing tool 7005; FIG. 71 illustrates a partial installation of prosthesis P 13 into the cavity by operation of force sensing tool 7005.

[0463] Tool 7005 includes an elongate member 7010, such as a shaft, rod, or the like. There may be many different embodiments but tool 7005 may include a mechanism for direct or indirect measurement of impact forces (mIF) such as by inclusion of an in-line sensor 1715. Further, tool 7005 allows for application of an external force applied to tool 7005. In some embodiments, another sensor 7020 may be used to measure this applied force as a theoretical maximum impact force (TMIF). In some cases, the TMIF is applied from outside and in other systems, the application is from tool 7005 itself. In some cases, there system 7000 has a priori knowledge of the force applied or it can estimate it without use of sensor 7020. Depending upon an implementation, various user interface elements and controls may be included, including indicators for various measured, calculated, and/or determined status information.

[0464] During operation, as mIF begins to approach TMIF, then system 7000 understands that prosthesis P is not moving much, if any, in response to the TMIF (when it is kept relatively constant). An advantage to the mechanical tools is their ability to repeatably apply a

known/predetermined force allowing for understanding of where the process is on an applicable FR curve for prosthesis P at installation site S. For example, in FIG. 71, the mIF, for a constant applied force, is closer to TMIF than in the case of FIG. 70. [0465] The arrangement of FIG. 70-FIG. 71 may be implemented in many different ways as further explained herein for improving installation and reducing risk of fracture.

[0466] FIG. 72 illustrates a set of parameters and relationships for a force sensing system 7200 including a generalized FR curve 7205 visualizing various applicable forces implicated in operation of the tool in FIG. 70 and FIG. 71. Curve 7205 includes TMIF vs displacement of the implant at the installation site. Early, a small change of TMIF can result is a relatively large change in displacement. However, near the magic spot, the curve starts to transition where the implant is close to being seated and increases in TMIF may result in little displacement change. And as TMIF increases, the risk of fracture increases.

[0467] In FIG. 72, a particular state is illustrated by "X" a point 7210 on curve 7205. A particular constant value of TMIF 7215 is applied to the system and prosthesis P moves along curve 7205. A measured Impact Force (mIF) 7220 approaches the value of TMIF 7215 as prosthesis P approaches point 7210. A resultant curve 7225 illustrates a difference between TMIF 7215 and mIF 7220. As prosthesis P approaches point 7210, resultant curve 7225 provides a valuable, previously unavailable quantitative indication of how prosthesis P was responding to applied forces. It may be that the procedure stops at point 7210, or a new, larger value for TMIF is chosen to move prosthesis P along curve 7205. System 7200 provides the surgeon with knowledge of where on curve 7205 the prosthesis P resides and provides an indication of a risk of fracture versus improving seating of prosthesis P. By monitoring resultant curve 7225 in some form, system 7000 understands whether prosthesis is moving or has become seated. Each of these pieces of information is useful to system 7200 and/or the surgeon until completion of the process.

[0468] FIG. 73-FIG. 78 illustrate a first specific implementation of the system and method of FIG. 70-FIG. 72, FIG. 73 illustrates a representative plot 7300 of insertion force for a cup during installation. As prosthesis P is being installed by a system, device, process, or tool, each increment of the active installation will have an applicable minimum impact to overcome resistive (e.g., static friction) forces. The impact force required increases as the insertion depth of the cup increases due to larger normal forces acting on the cup/bone interface (see FIG. 73). There is a tension between seating and increased force though, as larger impact forces raise the risk of fracture of surrounding bone. A goal of the surgeon is to reach a sufficient insertion depth to generate acceptable cup stability (e.g., pull-out resistance), while minimizing forces imparted to the acetabulum during the process. The process does not want to terminate early as the prosthesis may too easily be removed and the process doesn't want to continue too long until the bone fractures. This area is believed to be in the beginning of the non-linear regime in the plot of FIG. 73 as higher forces begin to have a smaller incremental benefit to cup insertion (i.e. smaller incremental insertion depth with larger forces).

[0469] FIG. 74 illustrates a first particular embodiment of a BMDX force sensing tool 7400. Tool 7400 allows indirect measurement of a rate of insertion of an acetabular cup and may be used to control the impact force being delivered to the cup based upon control signals and the use of features of FIG. 73. Tool 7400 may include an actuator 7405, a shaft 7410, and a force sensor 7415. One representative method for force measurement/response would employ such a tool 7400. Similar to the impaction rod currently used by surgeons, tool 7400 would couple to an acetabular cup (prosthesis P) using an appropriate thread at the distal end of shaft 7410. Actuator 7405 would couple to a proximal end of shaft 7410, and create controlled impacts that would be applied to shaft 7410 and connected cup P. The magnitude of the impact(s) would be controlled by the surgeon through a system control 7420, such as a dial or other input mechanism on the device, or directly by the instrument's software. System control 7420 may include a microcontroller 7425 in two-way communication with a user interface 7430 and receiving inputs from a signal conditioner 7435 receiving data from force sensor 7415. Controller 7425 is coupled to actuator 7405 to set a desired impact value.

[0470] Force sensor 7415 may be mounted between the shaft 7410 and acetabular cup P. Sensor 7415 would be of a high enough sampling rate to capture the peak force generated during an actuator impact. It is known that for multiple impacts of a given energy, the resulting forces increase as the incremental cup insertion distance decreases, see, for example, FIG. 75. FIG. 75 illustrates a graph including results of a drop test over time which simulate use of tool 7400 installing cup P into bone.

[0471] This change in force given the same impact energy may be a result of the frictional forces between cup P and surrounding bone of the installation site. For the plot of FIG. 75, the initial impact has a slow deceleration of the cup due to its relatively large displacement, resulting in a low force measurement. The displacement decreases for subsequent impacts due to the increasing frictional forces between the cup and bone, which results in faster deceleration of the cup (the cup is decelerating from the same initial velocity over a shorter distance). This results in an increase in force measurement for each impact. The maximum force for a given impact energy will be when the cup P can no longer overcome, responsive to a given impact force from the actuating system, the resistive (e.g., static friction) forces from the surrounding bone. This results in a "plateau", where any subsequent impact will not change either the insertion of cup P or the force measured.

[0472] In some embodiments, this relationship may be used to "walk up" the insertion force plot illustrated in FIG. 73, allowing tool 7400 to find the "plateau" of larger and larger impact energies. By increasing the energy linearly, the relationship between measured impact force and cup insertion illustrated in FIG. 75 should hold until the system reaches the non-linear insertion force regime of FIG. 73. When the non-linear regime is reached, a small linear increase in impact energy will not overcome the higher static forces needed to continue to insert the cup. This will result in an almost immediate steady state for the measured impact force (mIF of a force application X is about the same as MIF of a force application X+l). A visual representation of the measured impact force as the impact energy is increased is illustrated in FIG. 76. FIG. 76 illustrates a graph of measured impact force as impact energy is increased. Five impact energy levels are shown, with the last two increases in energy resulting in the cup entering the non-linear portion of the insertion force plot illustrated in FIG. 73.

[0473] A procedure for automated impact control/force measurement may include: a) begin impacts with a static, low energy; b) record the measured impact force (MIF); c) continue striking until the difference in measured impact force approaches zero (dMIF => 0), inferring that the cup is no longer displacing; d) increase the energy of the impacts by a known, relatively small amount; and e) repeat striking until plateau and increasing energy in a linear fashion until an increase in energy does not result in the relationship shown in FIG. 75. Instead, an increase in energy results in a "step function" in recorded forces, with an immediate steady-state. The user could be notified of each increase in energy, allowing a decision by the surgeon to increase the resulting impact force.

[0474] FIG. 77 illustrates a discrete impact control and measurement process 7700. Process 7700 includes step 7705-step 7745. Step 7705 (start) initializes process 7700. Process 7700 advances to a step 7710 to initiate the actuator to impart a known force application with energy X joules. After step 7710, process 7700 advances to step 7715 to measure impact force (MIF). After step 7715, process 7700 tests whether there have been a sufficient number of force applications to properly evaluate/measure a delta MIF (dMIF) between an initial value and a current value. When the test at step 7720 is negative, process 7700 returns to step 7710 to generate another force application event. Process 7700 continues with steps 7710-7720 until the test at step 7720 is affirmative, at which point process 7700 advances to a test at step 7725. Step 7725 tests whether the evaluated dMIF is approaching within a predetermined threshold of zero (that is, MIF(N) - MIF(N- 1) => 0 within a desired threshold. When the test at step 7725 is negative, process 7700 returns to step 7710 for produce another force application event and process 7700 repeats steps 7710-7725 until the test at step 7725 is affirmative.

[0475] When affirmative, process 7700 advances to a step 7730 and includes a user feedback event to inform a surgeon/observer that the prosthesis is no longer inserting at a given TMIF value. After step 7730, process 7700 may include a test at step 7735 as to whether the user desires to increase the TMIF. Some implementations may not include this test (and either automatically continue until a termination event or the system stops automatically).

[0476] In the test at step 7735, the user may choose to have the energy applied from the actuator increased. Process 7700 includes a step 7740 after an affirmative result of the test at step 7735 which increases the current energy applied by the actuator an additional Y joules. After the change of energy at step 7740, process 7700 returns to repeat steps 7710-7735 until the test at step 7735 is negative. At which point, process 7700 advances to an end step 7745 which may include any post-installation processing.

[0477] Once the non-linear regime discussed in FIG. 73 is reached, the probability of fracture increases. This is due to the acetabular cup nearing its full insertion depth, with limited incremental displacement from additional blows. This results in larger impact forces that are transmitted to the surrounding bone. Tool 7400 is able to detect when this regime is reached using process 7700, and could generate an alert through the user interface. The implementation of an alert could be performed in a number of different ways. One way would be a warning light and/or tone that would activate when a "step function" increase in measured impact force is detected. More advanced implementations are possible, with the system indicating the increasing probability of fracture as impact energy is increased once a "step function" increase in measured impact force is detected. The increasing risk of fracture could be shown through an LED bar that would illuminate additional lights to correspond to the relative risk, or by computing and displaying a fracture probability directly on the user interface. It should be noted that the cup may not fully seated when the system generates the aforementioned alert. This could be due to cup alignment issues, incorrect bone preparation, or incorrect cup sizing, among other causes. In these instances the system would generate an alert before the cup is fully inserted, allowing the surgeon to stop and determine the cause of the alert. This may be an additional benefit, allowing detection of an insertion issue before larger impact forces are used. A flowchart for one form of warning implementation is illustrated in FIG. 78.

[0478] FIG. 78 illustrates a warning process 7800. Process 7800 includes a step 7805-step 7840. Step 7805 (start) initializes process 7800. Process 7800 advances to a step 7810 to initiate the actuator to impart a known force application with energy X joules. After step 7810, process 7800 advances to step 7815 to measure impact force (MIF). After step 7815, process 7800 tests whether there have been a sufficient number of force applications to properly evaluate/measure a delta MIF (dMIF) between an initial value and a current value. When the test at step 7820 is negative, process 7800 returns to step 7810 to generate another force application event. Process 7800 continues with steps 7810-7820 until the test at step 7820 is affirmative, at which point process 7800 advances to a test at step 7825. Step 7825 tests whether the evaluated dMIF is approaching within a predetermined threshold of zero (that is, MIF(N) - MIF(N-l) => 0 within a desired threshold. When the test at step 7825 is negative, process 7800 returns to step 7810 for produce another force application event and process 7800 repeats steps 7810-7825 until the test at step 7825 is affirmative.

[0479] When affirmative, process 7800 advances to a step 7830 and includes a warning test event to test whether a first and a last MIF are within measurement error (MIF(0) = MIF(N)?) When the test at step 7830 is affirmative, a warning may be issued. When the test at step 7830 is negative, no warning is issued. There are similarities with process 7700 and process 7800 and some embodiments may combine them.

[0480] Improved performance may arise when the device is in the same state before each impact, in that the force applied by the user to the device is relatively consistent. Varying the user's input may influence the measured impact force for a strike, resulting in erroneous resistance curve modeling by the device. In order to minimize the occurrence, the device could actively monitor the force sensor between impacts, looking for a static load before within an acceptable value range. The system could also use the static load measurements directly before a strike as the impact's reference point, allowing relative measurements that reduce the effect of user variation. Even with this step, it is expected that filtering and statistical analysis may need to be performed in order to minimize signal noise.

[0481] FIG. 79-FIG. 84 illustrate a second specific implementation of the system and method of FIG. 70-FIG. 72; FIG. 79 illustrates a basic force sensor system 7900 for controlled insertion. System 7900 includes a handle 7905, a first force sensor 7910, a shock absorber 7915, a motor 7920, a second force sensor 7925, and impact rod 7930, and a processing unit 7935. A purpose of system 7900 is to use force measurements and estimates to provide cup settlement feedback. A basic configuration of the hardware involved in system 7900 is illustrated in FIG. 79. Important sensors include: Preload sensor 7910, motor current sensor located in PPU 7935; and impaction sensor 7925. Instrumentation of system 7900 either measures or estimates variables illustrated in FIG. 80. FIG. 80 illustrates an FR curve including TmlF and mIF as functions of displacement. FIG. 81 illustrates a generic force sensor tool to access variables of interest in FIG. 80. System 8100, corresponding generally to system 7000 includes a force sensor 8105 (measuring F), a damping mechanism 8110, a current sensor (TmlF estimation and Actuator) function 8115, a vibrating/impacting interface 8120, and a force sensor 8125 (measuring mIF).

[0482] Relationships among the three curves in FIG. 80 enable determination of a cup/cavity settlement behavior. mIF can be directly measured by system 7900 as described herein. For example, impaction sensor 7925 may be a force sensor placed in the impacting rod 7930. The impacting rod 7930 receives and transmits impacts directly to the cup. This same impaction force input is sensed by sensor 7925.

[0483] TmlF is composed by both preload and actuator force. The preload is measured directly by the force sensor 7910. The actuator force can be estimated by means of current sensing (motor 7920 and PPU 7935) as the torque/force generated by the motor can be related to its electric current. ] C. L. Chu, M. C. Tsai, H. Y. Chen, "Torque control of brushless dc motors applied to electric vehicles," in IEEE International Electric Machines and Drives Conference, 2001, pp. 82-87.

[0484] Motor 7920 is connected to PPU 7935 where the current sensor is installed. All measurements shall be properly filtered and handled in real-time before any advanced processing takes place. Both low level and advanced real-time processing are executed in PPU 7935 for each sensor. Sensor 7925 needs less processing since this is the direct measurement of mIF. TmlF needs more processing since it is composed by direct measurement of sensor 7910 and estimated force provided by motor 7920. Force estimation is basically data fusion of brushless DC motor current measurements with its electromechanical mathematical model considering mechanism interactions.

[0485] Once mIF and TmlF are internally available (to the PPU), the frequency of the actuating mechanism can be changed as a function of these variables. This allows the tool to track the optimal region (the B-Cloud) of the FR-Curve. It is important to note that mIF steady state value depends on current TmlF. In other words, the B -Cloud can be suitably tracked by the combination of both TmlF and mIF as described in the flowchart of FIG. 25.

[0486] FIG. 82 illustrates a B-cloud tracking process 8200 using TmlF and MIF

measurements. Process 8200 includes step 8205-step 8245. Step 8205, a start step, initiates process 8200. After start 8205, process 8200 includes a test step 8210 to determine whether TmlF = mIF. When negative, process 8200 performs a controlled action step 8215 and then returns to step 8210. Process 8200 repeats steps 8210-8215 until the test at step 8210 is affirmative, at which point process 8200 performs a test step 8220 to determine whether the B-cloud is achieved. When the test at step 8220 is negative, process 8200 performs a test step 8225 to determine whether to change the preload. When the test at step 8225 is negative, process 8200 performs a controlled action step 8230 and then branches to AA - to the test at step 8220.

[0487] When the test at step 8225 is affirmative, process 8200 queries the surgeon at step 8235 as to changing the preload. In response to surgeon consultation step 8235, process 8200 performs controlled action step 8230. Process 8200 repeats steps 8220-8235 until the test at step 8220 is affirmative. When affirmative, process 8200 performs a stop insertion step 8240 and may either ask surgeon at step 8230 and/or conclude process 8200 by performing an end step 8245.

[0488] Process 8200 begins when the cup is preloaded against the cavity. It may be triggered by force threshold or button press. Current TmlF and mIF are constantly compared and regulated to be equal according to an internal control system when they are not able to converge easily. The control system is detailed in FIG. 83. FIG. 83 illustrates a control system 8300 for the "controlled action" referenced in FIG. 82.

[0489] Control system 8300 includes a set of processing blocks, real objects, computed signals and raw measurement and computed signals selectively responsive to input force and input frequency commands. System 8300 includes a feedback block 8305, a Bcloud regulator block 8310, a control selector 8315, a device/cavity/cup interaction assessment 8320, an FR curve estimator 8325, a feedback block 8330, and a performance pursuit block 8335.

[0490] [0227] Feedback block 2605 compares TMIF against an output (input force command and mIF) of block 2620. When/If there is an Input Force error at block 2605, Bcloud Regulator provides a first input frequency command fl in response to the IF error. Feedback block 8330 compares a maximum feasible gain against a cup/cavity gain estimate from FR estimator 8325. When/if there is a gain error, performance pursuit 8335 takes this gain error and produces a second input frequency command. Control selector 8315 accepts both input frequency commands and selects one and provides it to the device/cavity/cup interaction 8320. Interaction 8320 produces input force command and mIF to FR estimator 8325, to selector 8315, and to feedback block 8305.

[0491] As the achievement of the B-Cloud is an objective, it is also constantly verified if it was achieved. However, the achievement of the B-Cloud is constrained to the value of the force source measured by TmlF. When the B-Cloud is not achieved, it is evaluated if there is need of preload increase or not (i.e. the actuator alone would be able to increase TmlF). In case of additional pre- load needed, the device asks the surgeon to increase the pre-load. The control system keeps running to make mIF track TmlF in an optimized way. The insertion stops automatically when the B-Cloud is achieved for the first time. A reference value inside the B-Cloud can be adjusted by the surgeon if she realizes based on its visual feedback that additional or less insertion force is necessary.

[0492] There are possible exceptions related to abnormal or unexpected cup/cavity behavior. As a cup/cavity which needs too much pre-load or much more force than some actuators are able to achieve. For this reason the "B-Cloud regulation" block 8310 in FIG. 83 may be implemented in two distinct ways: a BMD3 device alone (curve 8405 in FIG. 84 - mIF strong BMD3); or hybrid

BMD3/BMD4 devices combined (curve 8410 with "weak" mIF BMD3 switched to BMD4 - hybrid or discrete devices).

[0493] FIG. 84 illustrates possible B-cloud regulation strategies. A value on the B-Cloud is taken as reference for the B-Cloud regulator, this value is expressed by the dashed line in FIG. 84. In the case of a BMD3 able to perform the job alone, it can be achieved smoothly. In the case that BMD3 does not have sufficient power to accomplish the task, it may switch to BMD4 which provides incremental impacts proportional to the difference between mIF and TmlF. Progressive BMD4 impacts change its amplitude following KBMD4(miF-T_miF), while KBMD is a parameter which has to be determined experimentally.

[0494] Estimation of the force provided by the motor

[0495] A reliable and feasible way to determine the amount of force made available by the actuator is by means of electrical current measurement. The accuracy and sizes involved in some contexts of some embodiments would make difficult the installation of force/torque sensors for motors and piezo transducers, which are the basic types of actuators used in BMD3 and BMD4 devices. However, electrical current drawn by these actuators is related to the force produced by them. In other words, the force produced can be understood as a function of the electrical current. This idea is largely in engineering. Some embodiments may make effective use of estimators (e.g., Kalman filter) which relate the mathematical model of the electromechanical actuator fused with measured values of the electrical current to provide the force output generated in real-time by the actuator

[0496] FIG. 85 illustrates a generalized BMD 8500 including realtime invasive sense measurement. BMD 8500 includes one or more micro-electro-mechanical systems (MEMS) 8505 to measure realtime invasive sense measurement for BMD 8500. MEMS 8505 are secured to BMD 8500, such as by for example, an attachment or other coupling to a handle 8510 of BMD 8500. As illustrated, BMD 8500 includes an acetabular cup C for installation, though other systems may be used for different prosthetics.

[0497] During a procedure, MEMS 8505 provides realtime parametric evaluation of relevant information that may be needed or desired by an operator of handle 8510. For example, an orientation and seatedness of cup C may be evaluated in realtime to allow the operator to suspend operation when a desired orientation and/or seatedness has been achieved. MEMS 8505 may evaluate orientation, displacement depth, seatedness, using a range of potential sensing systems, including force, acceleration, vibration, acoustics, and other information. Just as an interaction between cup C and an installation site may produce an FR curve as described herein, various interactions of BMD 8500 or one or more components of BMD 8500 (e.g., cup C) with the installation site may produce characteristic profiles or "prints" that change during the realtime operation. Monitoring these parametric prints in true realtime may provide the operator with helpful information that is not available with a series of pre-process measurement and post-process measurement.

[0498] The force parameter has been described herein. Other parameters of acceleration, vibration, acoustic, and the like information may provide helpful information as well by including appropriate sensing structures for acceleration, vibration, acoustic, and the like. In the case of an installation depth of an acetabular cup, these parameters may help the operator to identify and differentiate between the three zones: too little seatedness zone, sweet zone, and fracture-risk zone. The specifics by which these zones are detected and identified are likely to be different however. [0499] BMD 8500, by appropriate selection of multiple sensing systems in MEMS 8505, may improve performance by providing a logical product of different parametric evaluations. That is, while any single parameter of force, acceleration, vibration, acoustic, or the like may offer improved performance, having multiple different sensors all operating in true realtime to

cross/double check can offer improved performance.

[0500] In some cases, a system may not identify that the prosthesis is in the sweet zone unless multiple parametric systems concur. In other cases, it may be that a first to detect a fracture- risk zone may result in suspension or termination of the installation process. Or that all systems must indicate adequate seatedness before stopping (possibly adding a further condition of providing no fracture risk detection).

[0501] Even without automatic detection of these zones, the combined information may useful to the operator in evaluating how to proceed with the installation to help maximize the desired orientation and seatedness without unnecessarily risking fracture.

[0502] Other procedures besides cup installation (e.g., installing a different type of prosthesis), other processes other than prosthesis installation (e.g., assembling a modular prosthesis), and other invasive operations (e.g., bone preparation), and other medical interventions that do not relate to prosthesis preparation, installation, and assembly may all benefit from providing true realtime analysis and feedback.

[0503] Feedback from a MEMS sensing system may be accomplished by one or more of a display or indicator on or integrated with the device, and/or an associated module in communication with the MEMS sensing system/display, a robot or navigation system in communication with the MEMS sensing system and/or an associated module.

[0504] The system and methods above has been described in general terms as an aid to understanding details of preferred embodiments of the present invention. In the description herein, numerous specific details are provided, such as examples of components and/or methods, to provide a thorough understanding of embodiments of the present invention. Some features and benefits of the present invention are realized in such modes and are not required in every case. One skilled in the relevant art will recognize, however, that an embodiment of the invention can be practiced without one or more of the specific details, or with other apparatus, systems, assemblies, methods, components, materials, parts, and/or the like. In other instances, well-known structures, materials, or operations are not specifically shown or described in detail to avoid obscuring aspects of embodiments of the present invention.

[0505] Reference throughout this specification to "one embodiment", "an embodiment", or "a specific embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention and not necessarily in all embodiments. Thus, respective appearances of the phrases "in one

embodiment", "in an embodiment", or "in a specific embodiment" in various places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, or characteristics of any specific embodiment of the present invention may be combined in any suitable manner with one or more other embodiments. It is to be understood that other variations and modifications of the embodiments of the present invention described and illustrated herein are possible in light of the teachings herein and are to be considered as part of the spirit and scope of the present invention.

[0506] It will also be appreciated that one or more of the elements depicted in the drawings/figures can also be implemented in a more separated or integrated manner, or even removed or rendered as inoperable in certain cases, as is useful in accordance with a particular application.

[0507] Additionally, any signal arrows in the drawings/Figures should be considered only as exemplary, and not limiting, unless otherwise specifically noted. Combinations of components or steps will also be considered as being noted, where terminology is foreseen as rendering the ability to separate or combine is unclear.

[0508] The foregoing description of illustrated embodiments of the present invention, including what is described in the Abstract, is not intended to be exhaustive or to limit the invention to the precise forms disclosed herein. While specific embodiments of, and examples for, the invention are described herein for illustrative purposes only, various equivalent modifications are possible within the spirit and scope of the present invention, as those skilled in the relevant art will recognize and appreciate. As indicated, these modifications may be made to the present invention in light of the foregoing description of illustrated embodiments of the present invention and are to be included within the spirit and scope of the present invention. [0509] Thus, while the present invention has been described herein with reference to particular embodiments thereof, a latitude of modification, various changes and substitutions are intended in the foregoing disclosures, and it will be appreciated that in some instances some features of embodiments of the invention will be employed without a corresponding use of other features without departing from the scope and spirit of the invention as set forth. Therefore, many

modifications may be made to adapt a particular situation or material to the essential scope and spirit of the present invention. It is intended that the invention not be limited to the particular terms used in following claims and/or to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include any and all embodiments and equivalents falling within the scope of the appended claims. Thus, the scope of the invention is to be determined solely by the appended claims.

Claims

CLAIMS What is claimed as new and desired to be protected by Letters Patent of the United States is:

1. An axially-impactful device for imparting a force on a portion of a prosthesis to be

installed in an installation direction with said prosthesis including an attachment structure, comprising:

a rod having a shaft including a proximal stop and a distal stop spaced apart from said proximal stop, said rod including a proximal end, a distal end spaced apart from said distal end, and a longitudinal axis extending from said proximal end to said distal end through said rod;

a hammer slidingly coupled to said shaft between said stops; and

an attachment system coupled to said distal end, said attachment system configured to both engage the attachment structure and align said longitudinal axis with the installation direction.

2. The device of claim 1 further comprising a force transfer engine coupled to said rod and to said hammer, said force transfer engine responding to an actuation control to move said hammer along said shaft towards said distal stop and subsequently have said hammer strike said distal stop with an axial installation force, said rod transferring said axial installation force to said distal end.

3. The device of claim 2 wherein said force transfer engine produces a predetermined axial installation force in response to said actuation signal.

4. The device of claim 2 wherein said force transfer engine includes a cockup mechanical apparatus having a spring coupled to said hammer.

5. The device of claim 3 wherein said force transfer engine includes a cockup mechanical apparatus having a spring coupled to said hammer.

6. The device of claim 2 wherein said force transfer engine includes a robot control

apparatus having a robotic actuator coupled to said hammer.

7. The device of claim 3 wherein said force transfer engine includes a robot control

apparatus having a robotic actuator coupled to said hammer.

8. The device of claim 2 wherein said force transfer engine includes a pneumatic apparatus including a pressurized fluid coupled to said hammer.

9. The device of claim 3 wherein said force transfer engine includes a pneumatic apparatus including a pressurized fluid coupled to said hammer.

10. The device of claim 3 wherein said predetermined axial installation force is fixed and non-adjustable.

11. The device of claim 3 wherein said predetermined axial installation force is variable and adjustable.

12. The device of claim 11 wherein said predetermined axial installation force is selected from a set of different predetermined values.

13. The device of claim 1 wherein the prosthesis includes an acetabular cup having a

generally semispherical exterior wall with an apex defining a prosthesis plane tangent to said exterior wall, wherein the attachment structure is disposed proximate said apex and parallel to said prosthesis plane, and wherein said rod is normal to said prosthesis plane.

14. The device of claim 13 wherein said distal stop includes an impact surface stricken by said hammer, and wherein said impact surface defines an impact plane generally coplanar with said prosthesis plane.

15. The device of claim 1 further comprising a pressure sensor coupled to said rod, said pressure sensor configured to provide feedback regarding an applied force to the prosthesis responsive to said hammer striking said distal stop.

16. The device of claim 1 further comprising a sound sensor acoustically coupled to the prosthesis, said sound sensor configured to provide feedback regarding a seatedness of the prosthesis at an installation site responsive to said hammer striking said distal stop.

17. The device of claim 15 further comprising a sound sensor acoustically coupled to the prosthesis, said sound sensor configured to provide feedback regarding a seatedness of the prosthesis at an installation site responsive to said hammer striking said distal stop.

18. The device of claim 1 wherein the prosthesis includes a component prosthesis having a trunnion and a head to be installed onto said trunnion, said trunnion including an installation axis, said head including a bore complementary to a taper of said trunnion with said bore including a bore axis with said bore axis aligned with said installation axis when said head is installed onto said trunnion taper, and wherein said attachment structure aligns said longitudinal axis with said bore axis and with said installation axis with the installation direction co-aligning said bore axis with said installation axis.

19. The device of claim 18 further comprising a force transfer engine coupled to said rod and to said hammer, said force transfer engine responding to an actuation signal to move said hammer along said shaft towards said distal stop and subsequently have said hammer strike said distal stop with an axial installation force, said rod transferring said axial installation force to said distal end.

20. The device of claim 18 further comprising a pressure sensor coupled to said rod, said pressure sensor configured to provide feedback regarding an applied force to the prosthesis responsive to said hammer striking said distal stop.

21. The device of claim 18 further comprising a sound sensor acoustically coupled to the prosthesis, said sound sensor configured to provide feedback regarding a seatedness of the prosthesis at an installation site responsive to said hammer striking said distal stop.

22. A method for imparting for imparting a force on a portion of a prosthesis to be installed in an installation direction with said prosthesis including an attachment structure, comprising:

a) coupling a rod to the attachment structure, said rod having a shaft including a proximal stop and a distal stop spaced apart from said proximal stop, said rod including a proximal end, a distal end spaced apart from said distal end, and a longitudinal axis extending from said proximal end to said distal end through said rod wherein said rod further includes a hammer slidingly coupled to said shaft between said stops; and

b) sliding said hammer along a path defined by said shaft to produce a strike against said distal stop;

c) transferring, responsive to said strike, an axially-constrained non-torqueing force to the prosthesis.

23. The method of claim 22 further comprising:

d) controlling an impact profile of said strike of said hammer against said distal stop using a force transfer engine coupled to said rod and to said hammer, said force transfer engine responding to an actuation control to move said hammer along said shaft towards said distal stop and subsequently have said hammer produce said strike against said distal stop with an axial installation force, said rod transferring said axial installation force to said distal end.

24. The method of claim 23 wherein said force transfer engine produces a predetermined axial installation force in response to said actuation signal.

25. The method of claim 23 wherein said force transfer engine includes a cockup mechanical apparatus having a spring coupled to said hammer.

26. The method of claim 24 wherein said force transfer engine includes a cockup mechanical apparatus having a spring coupled to said hammer.

27. The method of claim 23 wherein said force transfer engine includes a robot control

apparatus having a robotic actuator coupled to said hammer.

28. The method of claim 24 wherein said force transfer engine includes a robot control

apparatus having a robotic actuator coupled to said hammer.

29. The method of claim 23 wherein said force transfer engine includes a pneumatic

apparatus including a pressurized fluid coupled to said hammer.

30. The method of claim 24 wherein said force transfer engine includes a pneumatic

apparatus including a pressurized fluid coupled to said hammer.

31. The method of claim 24 wherein said predetermined axial installation force is fixed and non-adjustable.

32. The method of claim 24 wherein said predetermined axial installation force is variable and adjustable.

33. The method of claim 32 wherein said predetermined axial installation force is selected from a set of different predetermined values.

34. An axially-impactful device for imparting a force to a prosthesis to be installed in an installation direction with the prosthesis including an attachment structure, comprising: a rod having a shaft including a proximal end, a distal end spaced apart from said distal end, and a longitudinal axis extending from said proximal end to said distal end through said rod, said distal end including an engagement structure complementary to the attachment structure;

an impact energy control coupled to said proximal end;

a rocker assembly including a proximal end and a distal end, spaced away from said proximal end and coupled to said impact energy control;

a cam including a cam surface coupled to said proximal end of said rocker assembly; an engine producing a rotary engine motion; and

a gear train coupled to said engine and to said cam with said gear train configured to convert said rotary engine motion to a rotary cam motion of said cam surface.

35. The device of claim 34 wherein said cam surface includes a cam profile and wherein said impact energy control is responsive to said cam profile, and wherein said impact energy control periodically stores and releases energy to said shaft and is configured to produce a series of discrete impacts aligned with said longitudinal axis.

36. The device of claim 35 wherein each said discrete impacts has a predetermined

minimum impact force.

37. The device of claim 36 further comprising a variable control coupled to said impact energy control to set a desired variable value for said predetermined minimum impact force.

38. The device of claim 34 wherein said impact energy control includes a spring preload assembly.

39. The device of claim 34 wherein said impact energy control includes a friction-controlled assembly.

40. The device of claim 35 wherein said impact energy control includes a spring preload assembly.

41. The device of claim 35 wherein said impact energy control includes a friction-controlled assembly.

42. The device of claim 36 wherein said impact energy control includes a spring preload assembly.

43. The device of claim 36 wherein said impact energy control includes a friction-controlled assembly.

44. The device of claim 37 wherein said impact energy control includes a spring preload assembly.

45. The device of claim 37 wherein said impact energy control includes a friction-controlled assembly.

46. A method for imparting a force to a prosthesis to be installed in an installation direction with the prosthesis including an attachment structure, comprising:

a) rocking cyclically a first end of a first arm of a rocker assembly;

b) compressing cyclically an impact energy control coupled to said first arm responsive to said rocking step a);

c) releasing cyclically said impact energy control responsive to said rocking step c) to produce a series of discrete impacts; and

d) coupling said series of discrete impacts to the prosthesis through a shaft coupled to said impact energy control and to the prosthesis with said shaft having a longitudinal axis aligned with the installation direction; and

wherein said series of discrete impacts are aligned with said longitudinal axis.

47. An axially-impactful device for imparting a force to a prosthesis to be installed in an installation direction with said prosthesis including an attachment structure, comprising: a pneumatic engine producing a controllable air flow;

a rod having a shaft including a proximal end, a distal end spaced apart from said proximal end, an impact plate at said distal end, and a longitudinal axis extending from said proximal end to said distal end through said rod;

a slide, responsive to said controllable air flow, slidingly coupled to said shaft to deliver a series of discrete axial impacts against said impact plate; and an attachment system coupled to said distal end, said attachment system configured to both engage the attachment structure and align said longitudinal axis with the installation direction.

48. The device of claim 47 further comprising a force sensor coupled to said impact plate.

49. A device for imparting a force, comprising:

a rod having a shaft including a proximal end, a distal end spaced apart from said distal end, and a longitudinal axis extending from said proximal end to said distal end through said rod;

a motor producing a periodic motion;

a driver system, coupled to said proximal and to said motor, producing a driven rod motion for said distal end from said period motion;

an attachment system coupled to said distal end, said attachment system configured to engage an attachment structure; and

a set attachments, each particular attachment from said set of attachments including said attachment structure;

wherein said driven rod motion includes a selectable mode chosen from a mode group including a bidirectionally driven mode having a first driven direction and a second driven direction.

50. The device of claim 49 wherein said mode group further includes a first unidirectional mode and further comprising a mode selector to select a particular one mode from said bidirectionally driven mode and said first unidirectional mode.

51. The device of claim 49 wherein said bidirectionally driven mode includes a bidirectional longitudinal motion mode.

52. The device of claim 51 wherein said mode group further includes a first unidirectional longitudinal mode and further comprising a mode selector to select a particular one mode from said bidirectional longitudinal motion mode and said first unidirectional longitudinal mode.

53. The device of claim 49 wherein said bidirectionally driven mode includes a bidirectional rotational motion mode.

54. The device of claim 53 wherein said mode group further includes a first unidirectional rotational mode and further comprising a mode selector to select a particular one mode from said bidirectional rotational mode and said first unidirectional rotational mode.

55. The device of claim 49 wherein said set of attachments includes a bone reamer.

56. The device of claim 55 wherein said set of attachments includes a set of reamers

including a range of varying sizes and wherein said range of varying sizes include ½ millimeter variations.

57. The device of claim 53 wherein said set of attachments includes a bone reamer.

58. The device of claim 57 wherein said set of attachments includes a set of reamers

59. The device of claim 49 wherein said set of attachments includes an acetabular broach.

60. The device of claim 51 wherein said set of attachments includes an acetabular broach.

61. The device of claim 49 wherein said bidirectionally driven mode operates at an

ultrasonic frequency.

62. The device of claim 57 wherein said bidirectionally driven mode operates at an

ultrasonic frequency.

63. The device of claim 59 wherein said bidirectionally driven mode operates at an

ultrasonic frequency.

64. A method for imparting a force to a tool, comprising:

a) producing a periodic motion;

b) producing a driven rod motion for a distal end of a rod from said period motion; and

c) engaging said distal end with a particular one attachment from a set of attachments, said particular one attachment including the tool;

65. The method of claim 64 wherein said mode group further includes a first unidirectional mode and further comprising d) selecting a particular one mode from said bidirectionally driven mode and said first unidirectional mode.

66. The method of claim 64 wherein said bidirectionally driven mode includes a

bidirectional longitudinal motion mode.

67. The method of claim 66 wherein said mode group further includes a first unidirectional longitudinal mode and further comprising d) selecting a particular one mode from said bidirectional longitudinal motion mode and said first unidirectional longitudinal mode.

68. The method of claim 64 wherein said bidirectionally driven mode includes a

bidirectional rotational motion mode.

69. The method of claim 68 wherein said mode group further includes a first unidirectional rotational mode and further comprising d) selecting a particular one mode from said bidirectional rotational mode and said first unidirectional rotational mode.

70. The method of claim 64 wherein said particular one attachment includes a bone reamer.

71. The method of claim 70 wherein said set of attachments includes a set of bone reamers including a range of varying sizes and wherein said range of varying sizes include ½ millimeter variations.

72. The method of claim 68 wherein said particular one attachments includes a bone reamer.

73. The device of claim 72 wherein said set of attachments includes a set of reamers

74. The method of claim 64 wherein said particular one attachment includes an acetabular broach.

75. A modular prosthesis body, comprising:

a stem portion; a trunnion portion coupled to said stem portion, said trunnion portion having an insertion profile defining an insertion axis; and

a grip structure coupled to said trunnion portion and disposed on said insertion axis.

76. The modular prosthesis body of claim 75 wherein said trunnion portion includes a

trunnion taper symmetric about said insertion axis.

77. A system for assembly of a modular prosthesis including a stem portion, a trunnion

portion coupled to the stem portion, the trunnion portion having an insertion profile defining an insertion axis, and a prosthesis head configured to be installed on the trunnion portion and defining an installation aperture complementary to said insertion profile with the installation aperture defining an installation axis, comprising:

a head grasper including a housing defining a cavity complementary to an outer portion of the prosthesis head with said housing having a grasper axis extending through said cavity wherein said housing is configured to secure the prosthesis head within said cavity and align said grasper axis with the installation axis.

78. The system of claim 77 further comprising:

a grip structure coupled to the trunnion portion and disposed on the insertion axis; and a gripper including a first structure coupled to said grip structure and including a second structure coupled to said head grasper; and

wherein said gripper is configured to secure said head grasper relative to the trunnion portion while aligning said grasper axis with the insertion axis.

79. The system of claim 77 further comprising:

a tool, coupled to said head grasper, generating an assembly force aligned with said grasper axis.

80. The system of claim 78 further comprising:

81. The system of claim 79 wherein said tool includes a shaft coupling said head grasper and wherein said shaft includes a force sensing arrangement.

82. The system of claim 80 wherein said tool includes a shaft coupling said head grasper and wherein said shaft includes a force sensing arrangement.

83. The system of claim 79 wherein said tool includes a force engine producing said

assembly force.

84. The system of claim 83 wherein said force engine includes a torquer generating a torque and a converter coupled to said torque producing a decreasing displacement, responsive to said torque, of the prosthesis head relative to the stem.

85. The system of claim 83 wherein said force engine includes a motor generating a motion and a converter coupled to said motion producing a decreasing linear displacement, responsive to said motion, of the prosthesis head relative to the stem.

86. The system of claim 83 wherein said force engine includes an impulser generating a set of impulses and a converter coupled to said set of impulses producing a decreasing linear displacement, responsive to said motion, of the prosthesis head relative to the stem.

87. The system of claim 80 wherein said tool includes a force engine producing said

assembly force.

88. The system of claim 87 wherein said force engine includes a torquer generating a torque and a converter coupled to said torque producing a decreasing displacement, responsive to said torque, of the prosthesis head relative to the stem.

89. The system of claim 87 wherein said force engine includes a motor generating a motion and a converter coupled to said motion producing a decreasing linear displacement, responsive to said motion, of the prosthesis head relative to the stem.

90. The system of claim 87 wherein said force engine includes an impulser generating a set of impulses and a converter coupled to said set of impulses producing a decreasing linear displacement, responsive to said motion, of the prosthesis head relative to the stem.

91. The system of claim 81 wherein said tool includes a force engine producing said

assembly force.

92. The system of claim 91 wherein said force engine includes a torquer generating a torque and a converter coupled to said torque producing a decreasing displacement, responsive to said torque, of the prosthesis head relative to the stem.

93. The system of claim 91 wherein said force engine includes a motor generating a motion and a converter coupled to said motion producing a decreasing linear displacement, responsive to said motion, of the prosthesis head relative to the stem.

94. The system of claim 91 wherein said force engine includes an impulser generating a set of impulses and a converter coupled to said set of impulses producing a decreasing linear displacement, responsive to said motion, of the prosthesis head relative to the stem.

95. The system of claim 82 wherein said tool includes a force engine producing said

assembly force in realtime during application of said assembly force to said head grasper.

96. The system of claim 95 wherein said force engine includes a torquer generating a torque and a converter coupled to said torque producing a decreasing displacement, responsive to said torque, of the prosthesis head relative to the stem.

97. The system of claim 95 wherein said force engine includes a motor generating a motion and a converter coupled to said motion producing a decreasing linear displacement, responsive to said motion, of the prosthesis head relative to the stem.

98. The system of claim 95 wherein said force engine includes an impulser generating a set of impulses and a converter coupled to said set of impulses producing a decreasing linear displacement, responsive to said motion, of the prosthesis head relative to the stem.

99. A method, comprising:

a) installing a set of prosthetic heads onto a set of associated trunnions to produce a set of cold welds using a range of measured assembly forces; and

b) establishing, responsive to said range of measured assembly forces, a set of ranges of optimized assembly forces to predict production of a cold weld for a particular one prosthetic head installed onto a particular associated trunnion.

100. A modular prosthesis body, comprising:

a support portion;

a trunnion portion coupled to said support portion, said trunnion portion having an insertion profile defining an insertion axis; and

a grip structure coupled to said support portion and disposed in a first predetermined relationship to said insertion axis.

101. The modular prosthesis body of claim 100 wherein said first predetermined

relationship includes a disposition on said insertion axis.

102. The modular prosthesis body of claim 100 wherein said grip structure includes an irregular perimeter.

103. The modular prosthesis body of claim 102 wherein said irregular perimeter includes a polygon.

104. The modular prosthesis body of claim 100 wherein said grip structure includes

multiple cavities.

105. The modular prosthesis body of claim 100 wherein said support portion defines a trunnion channel having a channel insertion profile defining a channel axis and wherein said grip structure is disposed in a second predetermined relationship to said channel axis.

106. A modular prosthesis head having a body defining a trunnion cavity, the trunnion cavity having a trunnion installation axis, comprising:

an indicia disposed on an outer surface of the body, said indicia having a

predetermined relationship with the trunnion installation axis.

107. The modular prosthesis head of claim 106 wherein said predetermined relationship includes a disposition on said trunnion installation axis.

108. A modular prosthesis trunnion component having a body defining a trunnion portion coupled to a trunnion extension, the trunnion extension having a trunnion extension installation axis, comprising: an indicia disposed on an outer surface of the body, said indicia having a

predetermined relationship with the trunnion extension installation axis.

109. The modular prosthesis trunnion component of claim 108 wherein said predetermined relationship includes a disposition on said trunnion extension installation axis.

110. An anvil for a modular prosthesis head, the head defining a trunnion installation axis and an outer spherical perimeter surface, comprising:

a body defining a top planar surface, a bottom planar surface spaced apart from and parallel to said top planar surface, an anvil axis extending through and perpendicular to said planar surfaces and a depression defined in said top surface with said depression complementary to the outer spherical perimeter surface and symmetric about said anvil axis; and

an anvil axis interaction structure defined in said bottom surface with said anvil axis interaction structure symmetric about said anvil axis.

111. The anvil of claim 110 wherein the modular prosthesis head includes an indicia on an outer head surface aligned with the trunnion installation axis and wherein said anvil axis interaction structure includes an aperture extending into said depression.

112. The anvil of claim 111 wherein said indicia is visible through said aperture when said modular prosthetic head is installed in said depression and when said anvil axis is aligned with the trunnion installation axis.

113. The anvil of claim 110 wherein said anvil axis interaction structure is configured for receipt of an installation force applicator aligned with said anvil axis and trunnion installation axis.

114. An adapter for a modular prosthesis head, the head defining a trunnion installation axis, an outer spherical perimeter surface, and a planar face symmetric about the trunnion installation axis, comprising:

an anvil body defining a top planar surface, a bottom planar surface spaced apart from and parallel to said top planar surface, a circumferential channel in an outer surface of said anvil body disposed between and parallel to said planar surfaces, an anvil axis extending through and perpendicular to said planar surfaces and a depression defined in said top surface with said depression complementary to the outer spherical perimeter surface and symmetric about said anvil axis;

an anvil axis interaction structure defined in said bottom surface with said anvil axis interaction structure symmetric about said anvil axis; and

a shell defining a shell planar portion, a sidewall having an interior circumferential ledge complementary to said circumferential channel with said circumferential ledge spaced apart from and parallel to said shell planar portion and said sidewall further defining a shell cavity;

wherein said shell further defines a shell alignment axis when the modular prosthetic head is installed in said depression and both the modular prosthetic head and anvil are installed in said shell cavity with said shell alignment axis aligned with the trunnion installation axis and with said anvil axis.

115. The adapter of claim 114 wherein said planar face extends a first predetermined

distance away from said top surface when the modular prosthesis head is installed in said depression and said trunnion installation axis is aligned with said anvil axis and the planar face is parallel to said top planar surface, wherein said circumferential channel is spaced apart from said top planar surface by a second predetermined distance, and wherein said shell planar portion is spaced apart from said circumferential ledge by a third predetermined distance equal to a sum of said first predetermined distance and said second predetermined distance.

116. The adapter of claim 114 wherein said shell includes two or more shell portions.

117. The adapter of claim 114 wherein the modular prosthesis head includes an indicia on an outer head surface aligned with the trunnion installation axis and wherein said anvil axis interaction structure includes an aperture extending into said depression.

118. The adapter of claim 117 wherein said shell defines a shell bottom spaced apart from said shell planar portion, wherein said bottom surface extends through said shell bottom when the modular prosthetic head is installed in said depression and both the modular prosthetic head and anvil are installed in said shell cavity, and wherein said indicia is visible through said aperture when the modular prosthetic head is installed in said depression and both the modular prosthetic head and anvil are installed in said shell cavity and when said anvil axis is aligned with the trunnion installation axis.

119. The adapter of claim 114 wherein said anvil axis interaction structure is configured for receipt of an installation force applicator aligned with said shell alignment axis.

120. An apparatus for coupling an installation force from a force applicator to a modular prosthetic body when installing a modular prosthetic component to the modular prosthetic body, the modular prosthetic body defining a grip structure, comprising: a rigid clamp body including a grip structure engagement element configured to secure said clamp body to the modular prosthetic body, said clamp body further including a force applicator engagement element configured to secure said clamp body to the force applicator wherein the installation force is coupled from said force applicator without a flexing of said rigid clamp body by more than 10 microns.

121. An apparatus for a coupling of an installation force from a force applicator to a

modular prosthetic body when installing a modular prosthetic component to the modular prosthetic body, the modular prosthetic body defining a grip structure, comprising: a trunnion portion defined on the modular prosthetic body having a trunnion insertion axis;

a cavity portion defined in the modular prosthetic component having a trunnion engagement axis;

a force application axis aligned with a direction of the installation force; and a clamp body including a grip structure engagement element configured to secure said clamp body to the modular prosthetic body, said clamp body further including a force applicator engagement element configured to secure said clamp body to the force applicator;

wherein said clamp body maintains an alignment of all said axes during the coupling of the installation force.

122. The apparatus of claim 121 wherein the installation force is coupled from said force applicator without a flexing of said rigid clamp body by more than 10 microns.

123. An adapter for a modular prosthesis component, the component defining an

installation axis, an outer perimeter surface, and a component face symmetric about the installation axis, comprising:

an anvil body defining a top planar surface, a bottom planar surface spaced apart from and parallel to said top planar surface, a circumferential channel in an outer surface of said anvil body disposed between and parallel to said planar surfaces, an anvil axis extending through and perpendicular to said planar surfaces and a depression defined in said top surface with said depression complementary to the outer perimeter surface and symmetric about said anvil axis;

wherein said shell further defines a shell alignment axis when the modular prosthetic component is installed in said depression and both the modular prosthetic component and anvil are installed in said shell cavity with said shell alignment axis aligned with the installation axis and with said anvil axis.

124. An apparatus for coupling an installation force from a force applicator to a modular prosthetic body when installing a modular prosthetic component to the modular prosthetic body, the modular prosthetic body defining a grip structure, comprising: a clamp body including a grip structure engagement element configured to secure said clamp body to the modular prosthetic body, said clamp body further including a force applicator engagement element configured to secure said clamp body to the force applicator; and

a force measurement apparatus, coupled to said clamp body, configured to quantify the installation force.

125. A method for producing a modular prosthesis component, comprising:

producing a modular prosthetic body including a modular assembly portion having an assembly axis; and

defining a grip structure in said modular prosthetic body, said grip structure having a predetermined relationship to said assembly axis.

126. The method of claim 125 wherein said modular assembly portion includes a

component channel and wherein said predetermined relationship includes a disposition on said assembly axis.

127. A method of marking an assembly axis for a modular prosthetic head having a trunnion cavity defining the assembly axis, comprising:

establishing the assembly axis;

determining an intersection of the assembly axis with an outer surface of the modular prosthetic head; and

marking said intersection with a visible indicia.

128. A method for installing a modular prosthetic component having a first axis into an anvil having a second axis, comprising:

disposing the modular prosthetic component into a depression of the anvil; and aligning axially the modular prosthetic component with the anvil by aligning the axes.

129. The method of claim 128 wherein the modular prosthetic component includes a

visible indicia marking the first axis further comprising:

revealing the visible indicia through an aperture in the anvil when the axes are aligned.

130. The method of claim 128 further comprising:

enclosing the modular prosthetic component and the anvil with a shell that automatically aligns the axes.

131. The method of claim 128 further comprising:

providing an anvil axis interaction structure in a surface of the anvil, said anvil axis interaction structure symmetric about the second axis.

132. The method of claim 130 further comprising:

133. The method of claim 131 wherein said anvil axis interaction structure is configured for receipt of an installation force applicator aligned with the axes.

134. A method for joining a modular prosthetic component to a modular prosthetic body, comprising:

locking the modular prosthetic component to the modular prosthetic body while an assembly of the modular prosthetic component is aligned with an assembly axis of the modular prosthetic body; and thereafter applying, while said axes are locked in alignment, an assembly force to cold weld the modular prosthetic component to the modular prosthetic body wherein said assembly force is axially aligned with said axes.

135. A bone preparation tool, comprising:

a bone-processing implement configured to process an in-patient bone using a primary motion in a primary mode of freedom of motion; and

a motive system, coupled to said cutting implement, configured to operate said bone- processing implement in said primary mode of freedom of motion and in a secondary mode of motion, said secondary mode of freedom different from said primary mode of freedom wherein said secondary mode of freedom includes an ultrasonic vibratory motion.

136. The bone preparation tool of claim 135 wherein said bone-processing implement includes a saw blade and wherein said primary mode of freedom of motion includes a lateral reciprocating motion.

137. The bone preparation tool of claim 135 wherein said bone-processing implement includes a broach and wherein said primary mode of freedom of motion includes a longitudinally reciprocating motion.

138. The bone preparation tool of claim 135 wherein said bone-processing implement includes a reamer surface defining a longitudinal axis and wherein said primary mode of freedom of motion includes a rotation about said longitudinal axis.

139. The bone preparation of claim 138 wherein said secondary mode of freedom of motion includes a longitudinal motion for said ultrasonic vibratory motion.

140. The bone preparation tool of claim 135 wherein said bone-processing implement includes a burr defining a longitudinal axis and wherein said primary mode of freedom of motion includes a rotation about said longitudinal axis.

141. The bone preparation tool of claim 140 wherein said secondary mode of freedom of motion includes a longitudinal motion for said ultrasonic vibratory motion.

142. The bone preparation tool of claim 135 wherein said primary mode of freedom of motion includes a subsonic motion for said primary motion.

143. The bone preparation tool of claim 136 wherein said primary mode of freedom of motion includes a subsonic motion for said primary motion.

144. The bone preparation tool of claim 137 wherein said primary mode of freedom of motion includes a subsonic motion for said primary motion.

145. The bone preparation tool of claim 138 wherein said primary mode of freedom of motion includes a subsonic motion for said primary motion.

146. The bone preparation tool of claim 140 wherein said primary mode of freedom of motion includes a subsonic motion for said primary motion.

147. The bone preparation tool of claim 135 further comprising:

a constraint, coupled to said processing implement, configured to predefine a set of bone regions for said in-patient bone and further configured to monitor a relative location of said processing implement relative to a particular portion of said in-patient bone to be processed by said processing implement;

wherein said constraint provides a realtime feedback signal during bone processing regarding a desirability of processing said particular portion of said in-patient bone.

148. The bone preparation tool of claim 147 wherein said constraint includes a haptic robotic system and wherein said realtime feedback signal includes a realtime tactile cue that varies responsive to said particular portion.

149. The bone preparation tool of claim 147 wherein said wherein said set of bone regions includes a first subset of desirable bone regions to be processed.

150. The bone preparation tool of claim 149 wherein said realtime feedback signal limits processing of said particular portion when said particular portion is not part of said first subset of desirable bone regions to be processed.

151. The bone preparation tool of claim 148 wherein said constraint includes a haptic robotic system and wherein said realtime feedback signal includes a realtime tactile cue that varies responsive to said particular portion.

152. The bone preparation tool of claim 149 wherein said constraint includes a haptic robotic system and wherein said realtime feedback signal includes a realtime tactile cue that varies responsive to said particular portion.

153. A method for preparing an in-patient bone, comprising:

processing, using a bone-processing implement, the in-patient bone using a primary motion in a primary mode of freedom of motion for said a bone -processing implement; and concurrently

operating said a bone-processing implement in a secondary motion including a secondary mode of freedom of motion;

wherein said secondary mode of freedom is different than said primary mode of freedom of motion; and

wherein said secondary motion includes an ultrasonic vibration motion.

154. The method of claim 153 further comprising:

constraining said processing using a constraint system coupled to said processing implement not to process undesired portions of the in-patient bone wherein said constraint system identifies a set of desirable regions of the in-patient bone to be processed using said processing implement.

155. A force sensing system for a medical device tools with capacity to measure the force experienced by the system(mlF) - (Within the tool) and calculate a change in mIF with respect to time, number of impacts, or depth of insertion, wherein this system provides a feedback mechanism through the device, for the surgeon, as to when impaction should stop, and/or whether it should continue while assessing a risk of too early suspension with poor seating or too late when bone fracture risk is high and wherein this feedback mechanism can be created by measuring and calculating force, acceleration or insertion depth, among other variables.

156. A tool for inserting a prosthesis into a portion of a bone, comprising:

a shaft receiving an agency configured for an insertion of the prosthesis into the bone using said shaft; and

a first sensor coupled to said shaft providing a feedback of a response of said shaft to said agency during said insertion.

157. The tool of claim 156 wherein the prosthesis includes an acetabular cup and the portion of bone includes an acetabulum.

158. The tool of claim 156 wherein said agency includes an applied impact force and wherein said response includes a measured impact force.

159. The tool of claim 157 wherein said agency includes an applied impact force and wherein said response includes a measured impact force.

160. The tool of claim 159 wherein said first sensor is disposed within said shaft.

161. The tool of claim 159 further comprising a second sensor coupled to said shaft providing a measurement of said applied impact force.

162. The tool of claim 156 further comprising a processor coupled to said first sensor producing a metric responsive to an interaction of the prosthesis with the bone.

163. The tool of claim 157 further comprising a processor coupled to said first sensor producing a metric responsive to an interaction of the prosthesis with the bone.

164. The tool of claim 158 further comprising a processor coupled to said first sensor producing a metric responsive to an interaction of the prosthesis with the bone.

165. The tool of claim 159 further comprising a processor coupled to said first sensor producing a metric responsive to an interaction of the prosthesis with the bone.

166. The tool of claim 160 further comprising a processor coupled to said first sensor producing a metric responsive to an interaction of the prosthesis with the bone.

167. The tool of claim 161 further comprising a processor coupled to said sensors producing a metric responsive to an interaction of the prosthesis with the bone.

168. The tool of claim 167 wherein said metric includes a quality of insertion.

169. The tool of claim 156 wherein said agency includes an applied impact force and wherein said response includes a measured acceleration.

170. The tool of claim 169 further comprising a processor coupled to said first sensor producing a metric responsive to an interaction of the prosthesis with the bone.

171. The tool of claim 156 wherein said agency includes an applied impact force and wherein said response includes a measured wave response.

172. The tool of claim 171 further comprising a processor coupled to said first sensor producing a metric responsive to an interaction of the prosthesis with the bone.

173. A method for inserting a prosthesis into a portion of a bone, comprising:

using a shaft to receive an agency configured for an insertion of the prosthesis into the bone using said shaft; and

providing, using a first sensor coupled to said shaft, a feedback of a response of said shaft to said agency during said insertion.

174. The method of claim 173 further comprising:

producing, using a processor coupled to said first sensor, a metric responsive to an interaction of the prosthesis with the bone.

175. The method of claim 173 further comprising:

providing, using a second sensor coupled to said shaft, a measurement of said applied impact force.

176. The method of claim 175 further comprising:

producing, using a processor coupled to said sensors, a metric responsive to an interaction of the prosthesis with the bone.

177. An apparatus, comprising:

a medical device operating over a continuous period including an initial act with said medical device to a subsequent act with said medical device; and

a microelectromechanical (MEM) sensing system physically coupled to said medical device configured to provide a realtime parametric evaluation over said period.

178. The apparatus of claim 177 wherein said medical device includes a Behzadi Medical Device (BMD) for installation of an acetabular cup and wherein said realtime parametric evaluation includes a quality of a seatedness and fracture-risk for installation of said acetabular cup.

179. The apparatus of claim 177 wherein said MEM sensing system includes a force sensor.

180. The apparatus of claim 177 wherein said MEM sensing system includes an

acceleration sensor.

181. The apparatus of claim 177 wherein said MEM sensing system includes a vibration sensor.

182. The apparatus of claim 177 wherein said MEM sensing system includes an acoustic sensor.

183. The apparatus of claim 178 wherein said MEM sensing system includes a force sensor.

184. The apparatus of claim 178 wherein said MEM sensing system includes an

acceleration sensor.

185. The apparatus of claim 178 wherein said MEM sensing system includes a vibration sensor.

186. The apparatus of claim 178 wherein said MEM sensing system includes an acoustic sensor.

187. The apparatus substantially as disclosed herein.

188. The method substantially as disclosed herein.