WO2010111678A2

WO2010111678A2 - Orthopedic spacer system and method

Info

Publication number: WO2010111678A2
Application number: PCT/US2010/028959
Authority: WO
Inventors: Martin Roche; Marc Stein
Original assignee: Martin Roche; Marc Stein
Priority date: 2009-03-26
Filing date: 2010-03-26
Publication date: 2010-09-30
Also published as: US20100249787A1; US8906027B2; US20100250276A1; US20100249533A1; WO2010111678A3; US20100249790A1; US20100249788A1; US20100249535A1; US20100250571A1; US20100250284A1; US20100249791A1; US20100249534A1; US20100249665A1

Abstract

At least one embodiment is directed to a dynamic distractor (100) for distracting bones of a muscular-skeletal system. The dynamic distractor (100) comprises at least one sensor (108, 110), a handle (112, 804), a lift mechanism (302), and one or more alignment aids (502, 802). The position and measurement sensors (108, 110) are in communication with the processing unit (406) to display, process, and store measured data. The process of distraction separates two components such as bones of the muscular-skeletal system. A gap created by dynamic distractor (100) is adjustable under load. The at least one sensor (108, 110) can provide loading, loading differential, and position information as well as other measured parameters. Dynamic distractor (100) can aid in the alignment of the skeletal systems and to verify that alignment is correct. Soft tissue release can be performed with dynamic distractor (100) in place over a full range of motion.

Description

ORTHOPEDIC SPACER SYSTEM AND METHOD

CROSS-REFERENCE [0001] This application claims the priority benefits of U.S. Provisional Patent

Application No. 61/21 1 ,023 filed on March 26, 2009, the entire contents of which are

hereby incorporated by reference. This application further claims the benefit of U.S.

provisional patent applications No. 61/221 ,761 , 61/221 ,767, 61/221 ,779, 61/221 ,788,

61/221 ,793, 61/221 ,801 , 61/221 ,808, 61/221 ,817, 61/221 ,867, 61/221 ,874, 61/221 ,879,

61/221 ,881 , 61/221 ,886, 61/221 ,889, 61/221 ,894, 61/221 ,901 , 61/221 ,909, 61/221 ,916,

61/221 ,923, and 61/221 ,929 all filed 30 June 2009. The disclosures of which are

incorporated herein by reference in its entirety.

FIELD

[0002] The invention relates in general to orthopedics, and particularly though not exclusively, is related to distraction of the muscular-skeletal system and more specifically to the measurement of parameters of the muscular- skeletal system.

BACKGROUND

[0003] The skeletal system is a balanced support framework subject to variation and degradation. Changes in the skeletal system can occur due to environmental factors, degeneration, and aging. An orthopedic joint of the skeletal system typically comprises two or more bones that move in relation to one another. Movement is enabled by muscle tissue and tendons attached to the skeletal system of the joint. Ligaments hold and stabilize the one or more joint bones positionally. Cartilage is a wear surface that prevents bone-to- bone contact, distributes load, and lowers friction. The spinal column is comprised of vertebrae, discs, ligaments, and muscles that stabilize the vertebral column and protects the spinal nerves.

[0004] There has been substantial growth in the repairing of the human skeletal system as orthopedic joint implant technology has evolved. In general, improvements to orthopedic implant joints have been based on empirical data that is sporadically gathered from real patients. Similarly, the majority of implant surgeries are being performed with tools that have not changed substantially in decades but have been refined over time. In general, the orthopedic implant procedure has been standardized to meet the needs of the general population. Adjustments due to individual skeletal variations rely on the skill of the surgeon to adjust the process for the exact circumstance. At issue is that there is little or no data during an orthopedic surgery, postoperatively, and long term that provides feedback to the orthopedic manufacturers and surgeons about the implant status.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Exemplary embodiments of present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:

[0006] FIG. 1 is a top view of a dynamic distractor in accordance with an exemplary embodiment;

[0007] FIG. 2 is a side view of a dynamic distractor having a minimum height in accordance with an exemplary embodiment;

[0008] FIG. 3 is a view of a dynamic distractor opened for distracting two surfaces from each other in accordance with an exemplary embodiment;

[0009] FIG. 4 is an anterior view of a dynamic distractor placed in a knee joint in accordance with an exemplary embodiment;

[0010] FIG. 5 is a lateral view of dynamic distractor in a knee joint positioned in flexion in accordance with an exemplary embodiment;

[0011] FIG. 6 is a lateral view of a dynamic distractor in a knee joint coupled to a cutting block in accordance with an exemplary embodiment;

[0012] FIG. 7 is an anterior view of a cutting block coupled to dynamic distractor in accordance with an exemplary embodiment; [0013] FIG. 8 is an illustration of dynamic distractor including alignment in accordance with an exemplary embodiment;

[0014] FIG. 9 is a side view of a leg in extension with a dynamic distractor in the knee joint region in accordance with an exemplary embodiment;

[0015] FIG. 10 is a top view of a leg in extension with a dynamic distractor in the knee joint area in accordance with an exemplary embodiment;

[0016] FIG. 11 is an illustration of a system for measuring one or more parameters of a biological life form in accordance with an exemplary embodiment;

[0017] — FIG. 12 depicts an exemplary diagrammatic representation of a machine in the form of a computer system within which a sot of instructions, when oxocutod, may cause tho machine to perform any one or more of tho methodologies discussed above;

[0018] FIG. 12 is an illustration of a communication network for measurement and reporting in accordance with an exemplary embodiment:

[0019] FIG. 13 is an illustration of a communication network for measurement and reporting in accordance with an exemplary embodiment;

[0020] FIG. 14 is an exemplary method for distracting surfaces of the muscular-skeletal system in accordance with an exemplary embodiment;

[0021] FIG. 15 is an exemplary method for distracting surfaces of the muscular-skeletal system in extension and in flexion in accordance with an exemplary embodiment;

[0022] FIG. 16 is an exemplary method for distracting surfaces of the muscular-skeletal system in extension and in flexion in accordance with an exemplary embodiment;

[0023] FIG. 17 is an exemplary method for distracting surfaces of a knee joint in extension and in flexion in accordance with an exemplary embodiment; [0024] FIG. 18 is an exemplary method to place the muscular-skeletal system in a fixed position for bone shaping in accordance with an exemplary embodiment;

[0025] FIG. 19 is an exemplary method of measuring the muscular-skeletal system in accordance with an exemplary embodiment;

[0026] FIG. 20 is an exemplary method of a disposable orthopedic system in accordance with an exemplary embodiment;

[0027] FIG. 21 is an exemplary method of a disposable orthopedic system in accordance with an exemplary embodiment;

[0028] FIG. 22 is a diagram illustrating a data repository and registry for evidence based orthopedics in accordance with at least one exemplary embodiment;

[0029] FIG. 23 is a diagram illustrating an orthopedic lifecycle approach to manage orthopedic health based on patient clinical evidence in accordance with at least one exemplary embodiment.

[0030] FIG. 24 is an illustration of a sensor placed in contact between a femur and a tibia for measuring a parameter in accordance with an exemplary embodiment;

[0031] FIG. 25 is a simplified cross-sectional view of a sensing module (or assemblage) in accordance with an exemplary embodiment;

[0032] FIG. 26 is an exemplary assemblage for illustrating reflectance and unidirectional modes of operation;

[0033] FIG. 27 is an exemplary assemblage that illustrates propagation of ultrasound waves within the waveguide in the bi-directional mode of operation of this assemblage;

[0034] FIG. 28 is an exemplary cross-sectional view of a sensor element to illustrate changes in the propagation of ultrasound waves with changes in the length of a waveguide; [0035] FIG. 29 is an exemplary block diagram of a measurement system in accordance with one embodiment;

[0036] FIG. 30 is a measurement system operating in pulsed echo mode with digital output according to one embodiment;

[0037] FIG. 31 is a timing diagram of the measurement system in according to one embodiment;

[0038] FIG. 32 is an exemplary block diagram of the components of a sensing module; and

[0039] FIG. 33 is an exemplary block diagram of a positive feedback closed-loop measurement system in pulsed mode in accordance with one embodiment.

DETAILED DESCRIPTION

[0040] The following description of exemplary embodiment(s) is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0041] Processes, techniques, apparatus, and materials as known by one of ordinary skill in the art may not be discussed in detail but are intended to be part of the enabling description where appropriate. For example specific computer code may not be listed for achieving each of the steps discussed, however one of ordinary skill would be able, without undo experimentation, to write such code given the enabling disclosure herein. Such code is intended to fall within the scope of at least one exemplary embodiment.

[0042] Additionally, the sizes of structures used in exemplary embodiments are not limited by any discussion herein (e.g., the sizes of structures can be macro (centimeter, meter, and size), micro (micrometer), nanometer size and smaller).

[0043] Notice that similar reference numerals and letters refer to similar items in the following figures, and thus once an item is defined in one figure, it may not be discussed or further defined in the following figures. [0044] In all of the examples illustrated and discussed herein, any specific values, should be interpreted to be illustrative only and non-limiting. Thus, other examples of the exemplary embodiments could have different values. [0045] In general, successful orthopedic surgery including the implantation of an orthopedic device into the muscular-skeletal system depends on multiple factors. One factor is that the surgeon strives to maintain adequate alignment of the extremity or implanted device to the ideal. A second factor is proper seating of an implant for stability. A third factor is loading on the skeletal system or replacement implant. A fourth factor is alignment of implanted components in relation to one another. A fifth factor is balance of loading over a range motion.

[0046] By way of a device herein contemplated, the surgeon receives measured data during surgery and post operatively on the factors listed above. As one example, accurate measurements can be made during orthopedic surgery to determine if bones or an implant are optimally balanced and aligned. This can reduce operating time and surgical stress for both the surgeon and patient. The data generated by direct measurement can be further processed to assess long-term integrity based on maintaining surgical parameters within predetermined ranges. The measured data in conjunction with patient information can lead to improved design and materials. [0047] FIG. l is a top view of a dynamic distractor 100 in accordance with an exemplary embodiment. Dynamic distractor 100 is also known as a dynamic spacer block. Dynamic distractor 100 is a sensored device that is used during surgery of a muscular-skeletal system. Dynamic distractor 100 can be used in conjunction with other tools common to orthopedic surgery as will be disclosed in more detail hereinbelow. In at least one exemplary embodiment, the system is used during orthopedic joint surgery and more specifically during implantation of an artificial joint. The system uses one or more sensors intra-operatively to define implant loading, positioning, achieve appropriate implant orientation, balance, and limb alignment. In particular, dynamic distractor combines the ability to align and measure one or more other parameters (e.g. load, blood flow, distance, etc ..) that provides quantitative data to a surgeon that allows the orthopedic surgery to be measured and adjusted within predetermined values or ranges based on the measured data and a database of other similar procedures. The system is designed broadly for use on the skeletal system including but not limited to the spinal column, knee, hip, ankle, shoulder, wrist, articulating, and nonarticulating structures.

[0048] Dynamic distractor 100 comprises an upper support structure and a lower support structure. An active or dynamic spacer portion 120 of dynamic spacer block comprises the upper and lower support structures. A lift mechanism (not shown) couples to an interior surface of upper support structure and an interior surface of the lower support structure. A handle 1 12 couples to the lift mechanism. In one embodiment, handle 1 12 is operatively coupled to the lift mechanism to change a gap of the spacer block. Handle 1 12 can also be used to guide dynamic distractor 100 between regions of the muscular-skeletal system. In general, the upper support structure has a superior surface 102 that interfaces with a surface of the muscular-skeletal system. Similarly, the lower support structure has an inferior surface that interfaces with a surface of the muscular-skeletal system.

[0049] In one embodiment, handle 1 12 can be rotated to adjust the lift mechanism to increase or decrease a gap between the superior and inferior surfaces of the active spacer block thereby modifying the height or thickness of dynamic distractor 100. In a non-limiting example to illustrate a disposable aspect, superior surface 102, the inferior surface, or both surfaces include at least one cavity or recess for housing at least one sensor module. The sensor module includes at least one sensor for measuring a parameter of the muscular-skeletal system. For example, the sensor can measure a force or pressure. As will be disclosed hereinbelow, the sensor can be disabled so it cannot be reused and disposed of after the procedure has been performed. In a further example, dynamic distractor 100 can be placed between two or more bone surfaces such that the superior surface 102 and the inferior surface contact surfaces of the muscular-skeletal system related to a joint. In one embodiment, the sensor is coupled to a surface of the muscular-skeletal system for measuring a parameter when positioned between surfaces. Handle 1 12 can be rotated to different gap heights allowing pressure measurements at the different gap heights to generate data of gap versus pressure.

[0050] Handle 1 12 further includes an opening 1 14, a decoupling mechanism 1 18, and a display 1 16. Opening 1 14 is used to receive additional components of the system that will be described in more detail hereinbelow. Decoupling mechanism 1 18 allows removal of the handle during parts of a surgery to allow access to the muscular-skeletal system. Decoupling mechanism 1 18 couples to a locking mechanism that locks handle 1 12 to a shaft of the lift mechanism. Decoupling mechanism 1 18 releases the locking mechanism thereby allowing handle 1 12 to be removed from dynamic distractor 100. In one embodiment, the locking mechanism is a pin or ball that fits into a corresponding feature 122 on the shaft of the lift mechanism. Decoupling mechanism 1 18 releases or frees the pin or ball from feature 1 122 thereby allowing removal of handle 1 12. Alternatively, decoupling mechanism 1 18 can be a hinge or joint that allows handle 1 12 to move in a direction that allows greater access by the surgeon to an area where the spacer block portion of dynamic distractor 100 has been placed. The display 1 16 on handle 1 12 can provide a readout of the gap between the superior surface 102 and the inferior surface as handle 1 12 is rotated to adjust spacing.

[0051] In a non-limiting example, dynamic distractor 100 is adapted for use in artificial knee implant surgery. It should be noted that dynamic distractor 100 can be similarly adapted for other orthopedic surgery where both distraction and parameter measurement is beneficial. A knee implant is used merely as an example to illustrate how dynamic distractor 100 can be used in a surgical environment. In at least one exemplary embodiment, the superior surface 102 of dynamic distractor 100 includes a recess or cavity 104 and a second recess or cavity 106. In one embodiment, a sensor 108 and a sensor 1 10 are pre-sterilized in one or more packages. The packaging is opened prior to or during surgery within the surgical zone to maintain sterility. Sensors 108 and sensor 1 10 are shown respectively placed in cavities 104 and 106 for measuring a parameter that aids in the surgical procedure. In the knee example, sensors 108 and 1 10 include pressure sensors such as strain gauges, mechanical-electrical-machined (mems) sensors, diaphragm structures, mechanical sensors, or other pressure measuring devices. In one embodiment, a major exposed surface of sensors 108 and 1 10 is in contact with the muscular-skeletal system after insertion. Alternatively, one or more layers of material or portions of the muscular-skeletal system can be between sensors 108 and 1 10 such that the parameter can be measured or transferred through the intervening layers. A force or pressure applied to the exposed surfaces is measured by sensors 108 and 1 10 while the gap of the dynamic distractor is adjusted. Alternatively, the lift mechanism in conjunction with sensors 108 and 1 10 can be set to a predetermined pressure. The lift mechanism gap will increase until the predetermine pressure is reached. Thus, identifying a gap height or thickness of dynamic distractor 100 to achieve the predetermined pressure.

[0052] In at least one exemplary embodiment, sensors 108 and 1 10 are disposable devices. After measurements have been taken, sensors 108 and 1 10 can be removed and disposed of in an appropriate manner. Alternatively, the sensors 108 and 1 10 can be permanent or an integral part of the superior surface of dynamic distractor 100. The housing can be designed to be reused and to withstand a sterilization process after each use. The main body of dynamic distractor 100 as well as sensors 108 and 1 10 are cleaned and sterilized before each surgical usage.

[0053] Dynamic distractor 100 in a zero gap (or closed condition) is less than 8 millimeters thick for the knee application and can expand using the lift mechanism to greater than 25 millimeters. This range is sufficient for the majority of artificial knee implant surgeries being performed. The spacer portion 120 of dynamic distractor 100 contains the superior surface 102 and the inferior surface that articulates to at least two bone ends of the muscular- skeletal system. In the knee example, the dynamic distractor 100 is placed between the distal end of the femur and the proximal end of the tibia. As mentioned previously sensors 108 and 1 10 are in a housing. In one embodiment, the housing includes sensor elements to define the loads on the medial and lateral compartments. The sensored elements can comprise load displacement sensors, accelerometers, GPS locators, telemetry, power management circuitry, a power source and an ASIC.

[0054] As disclosed above, the spacer portion 120 of dynamic distractor 100 is placed between the femur and tibia in extension. The dynamic distractor 100 is configured with no gap (e.g. minimum height or thickness) or having a gap that can be inserted and removed without tissue damage. In general, the gap can be increased by rotating handle 1 12 after insertion such that the inferior surface of dynamic distractor 100 contacts a prepared surface of a proximal end of a tibia and the superior surface contacts the prepared distal end of the femur. In general, the femoral and tibial cuts in extension are made parallel to one another. Similarly, the femoral cut in flexion is made parallel to the prepared end of the tibia. The gap is measured to determine a combined thickness of the implants with the leg in extension. The prepared ends of the tibia and femur can be checked for alignment with the mechanical axis at this time as will be disclosed in detail below.

[0055] Typically, the surgeon selects the artificial components based on the cross-sectional size of the prepared bones. The variable component of the implant surgery is the final insert. The final insert has one or more bearing surfaces for interfacing with a femoral implant. In one embodiment, the measured gap height created by dynamic distractor 100 is used to define an insert thickness or height. The thickness of a final insert can change during surgery as further bone cuts or tissue tensioning occurs. Dynamic distractor 100 can be used during surgery to measure loading and gap height after each bone modification or after an orthopedic component has been implanted.

[0056] Dynamic distractor 100 can also be used to obtain an optimal balance. Balance is related to the measured loading between two or more areas. The measured values can than be adjusted to a predetermined relationship and within a predetermined value range. In the knee example, balance is associated with the differential pressure applied by each condyle on the bearing surfaces of the implant. Ideally, a predetermined surface area of the femoral implant condyle contacts the bearing surface to distribute the load and minimize wear. In a non-limiting example, a predetermined relationship between measured values by sensors 108 and 1 10 of dynamic distractor 100 is maintained after implantation of the artificial components. In one embodiment, the balance of the knee is maintained by having the measured load in each compartment approximately equal. A method to balance the loading of the compartments is through ligament release on the side having the larger loading value. Ligament release reduces loading primarily on the adjacent compartment. The loading can be read off a display on dynamic distractor 100 allowing the surgeon to view the change in loading and the differential value with each release. The lift mechanism provides sufficient room between the superior and inferior surfaces of dynamic distractor 100 for a surgeon to perform a release procedure without removing the device. A next greater thickness of an insert can be selected should the absolute loading value on each condyle fall outside the predetermined range due to the soft tissue release. Handle 1 12 can be rotated to increase the gap height to the next larger insert value to ensure the measured loading falls within the predetermined range and the differential loading falls within a predetermined range (after the soft tissue release).

[0057] The loading and balance of an implanted joint should be maintained within the predetermined values throughout the range of motion. In at least one exemplary embodiment, measurements are taken when the tibia is at a ninety-degree angle to the femur. Handle 1 12 is used to position the spacer block portion of distractor 100 between the femur and the tibia. The inferior surface of dynamic distractor 100 is in contact with the prepared surface of the tibia. In one embodiment, the superior surface 102 is in contact with the remaining portion of the condyles of the femur. Thus, the condyle surfaces of the femur are in contact with sensors 108 and 110 on the superior surface of dynamic distractor 100. In the example, a gap height of dynamic distractor 100 is reduced to accommodate the condyles that remain on the distal end of the femur in flexion. The gap height of dynamic distractor 100 can then be adjusted to a height corresponding to the gap height in extension less the thickness of the femoral implant whereby the leg in flexion is similar to the leg in extension. [0058] The loading on sensors 108 and 1 10 with the leg in flexion can be measured. The measurement is of value if the condyles are not damaged or degraded. In one embodiment, soft tissue release is used to adjust the balance between compartments with the leg in flexion. The soft tissue release can also be performed later in the procedure after the femoral implant has been implanted. Similar to the leg in extension, soft tissue release is performed to reduce the tension on the side having the higher compartment reading with dynamic distractor 100 in place. After soft tissue release, the readings in each compartment should be within a predetermined differential range. The distal end of the femur can then be prepared for receiving the femoral implant, which removes the remaining portion of the condyles. As disclosed, the surface of the femur is prepared to be parallel to the prepared tibial surface in flexion. This can be achieved by specific ligament releases in flexion, and /or rotation of the femoral implant to achieve parallel levels between the posterior femoral condyles and proximal tibia. A femoral sizer can be attached to the distractor to allow sizing of the femur coupled with rotation of the femur. This allows dynamic rotation to obtain equally balanced flexion compartments.

[0059] In a non-limiting example, the femoral implant component can be temporarily attached to the distal end of the femur. Measurements can be taken throughout the entire three-dimensional range of motion using dynamic distractor 100 to ensure that the implanted knee operates similarly in all positions. A gap provided by dynamic distractor 100 would be adjusted to a combined thickness of the final insert thickness and the tibial implant thickness. Dynamic distractor 100 can incrementally increase or decrease the gap to allow the surgeon to determine how different insert thicknesses affect load and balance measurements. In one embodiment, accelerometers are used to provide position and relational positioning information. The data can be stored in memory for later use or displayed to provide instant feedback to the surgeon on the implant status. Further adjustments to load and balance can be made with dynamic distractor in place if desired over different positions within the range of motion. Although one implant sequence is disclosed, it is well known that surgeons have different approaches, methodologies and procedure sequences. The use of dynamic distractor 100 would be applied similarly to distract and measure in different relational positions with the device in place. Furthermore, the device can be used or modified for use on different parts of the anatomy of the muscular-skeletal system.

[0060] FIG. 2 is a side view of dynamic distractor 100 having a minimum height in accordance with an exemplary embodiment. Dynamic distractor comprises an upper support structure 202 having superior surface 102 and a lower support structure 204 having an inferior surface 206. In the example, upper support structure 202, the lift mechanism, and lower support structure 204 supports loading typical for a joint of the muscular-skeletal system. Upper and lower support structures 202 and 204 comprise a rigid and load bearing materials such as metals, composite materials, and plastics that will not flex under loading. In one embodiment, stainless steel is used in the manufacture of the lift mechanism and upper and lower support structures 204 and 202.

[0061] Dynamic distractor 100 is used to distract surfaces of the muscular- skeletal system. Dynamic distractor 100 can be used in an invasive procedure such as orthopedic surgery. In the non-limiting example, dynamic distractor 100 can distract surfaces of the muscular-skeletal system in a range of approximately 8 millimeters to 25 millimeters. The support surfaces of dynamic distractor 100 do not flex under loading of the muscular-skeletal system. In one embodiment, dynamic distractor 100 has a minimum height or thickness between support surfaces of less than 8 millimeters. In at least one application, a space between support structures 202 and 204 is provided when dynamic distractor 100 is opened to a height greater than the minimum height. The space between support structures 202 and 204 when opened allows a surgeon to perform soft tissue release with the device in place.

[0062] A cavity 104 is illustrated in superior surface 102 of upper support structure 202. The cavity 104 is shaped similarly to a housing 210 of sensor 108. Housing 210 is placed within cavity 108 for measuring a compressive force applied across superior surface 102 and inferior surface 206. In the knee example, a condyle (implanted or natural) couples to an exposed surface of sensor 108. A pressure or force applied to sensor 108 is measured and displayed by dynamic distractor 100. Sensor 1 10 is shown placed in its corresponding cavity in superior surface 102. In one embodiment, the exposed surfaces of sensors 108 and 1 10 are approximately planar to the superior surface 102. The exposed surface of sensor 108 and 1 10 can be flat or contoured. Sensors 108 and 1 10 can be removed from upper support structure 202 and disposed after the surgery has been performed. In one embodiment, a push rod is exposed in the interior surface of upper support structure 202 that when pressed can apply a force to housing 210 that removes sensor 108 from cavity 208

[0063] In one embodiment, housing 210 is formed of a plastic material. The sensor and electronic circuitry is fitted in housing 210. The electronic circuitry comprises one or more sensors 220, one or more accelerometers 222, an ASIC integrated circuit 224, a power source 226, power management circuitry 228, GPS circuitry 230, and telemetry 232. The power source 226 can be a battery or other temporary power source that is coupled to the electronic circuitry prior to surgery. The power source 226 has sufficient power to enable the circuitry for a period of time that will cover the vast majority of surgeries. The power management circuitry 228 works in conjunction with the power source to maximize the life of the power source by disabling system components when they are not being used. In general, an ASIC circuit controls and coordinates when sensing occurs, can store data to memory, and can transmit data in real time or collect and send data at a more appropriate time to a remote system for further processing. The ASIC includes multiple ports that couple to one or more sensors 220. The ASIC couples, to at least one sensor 220, at least one accelerometer 222, GPS 232, and telemetry circuitry 232. The ASIC 222 can include the integration of telemetry circuitry 232, power management circuitry 228, GPS circuitry 230, memory, and sensors 220 to further reduce the form factor of the sensing system. In the example, the at least one sensor 220 is a pressure sensor that is coupled to the exposed surface of the housing. The pressure sensor converts the pressure to an electrical signal that is received by the ASIC. The at least one accelerometer 222 and GPS 232 provides positioning information at the time of sensing. Telemetry circuitry 232 communicates through a wired or wireless path. In one embodiment, the data is sent to a remote processing unit that can process and display information for use by the surgeon or medical staff. One or more displays 234 can be placed on dynamic distractor 100 to simplify viewing of a pressure or force measured by sensors 108 and 1 10 thereby allowing real time loading and balance differential to be seen at a glance. The information can be stored in memory on the sensor or transmitted to a database for long-term storage and processing.

[0064] In a zero gap or minimum height condition, the lift mechanism is enclosed within the device. An opening 212 exposes a threaded rod 216 that is a component of the lift mechanism. The exposed end portion of threaded rod 216 is shaped for receiving handle 1 12. For example, a proximal end 214 of handle 212 is shown having a hexagonal opening that operatively couples to a hexagonal shaped end of threaded rod 216. The surfaces of the hexagonal surface mate with the surfaces of the threaded rod for distributing the torque required to rotate threaded rod 216 when increasing a gap between superior surface 102 and inferior surface 206 to distract surfaces of the muscular-skeletal system. Distributing the torque over a large surface area prevents stripping of either the hexagonal shaped opening of handle 212 or the hexagonal shaped exposed end of threaded rod 216 when the device is under load. In one embodiment, a release and locking mechanism fastens handle 1 12 to threaded rod 216. Pressing or sliding unlocking button 218 releases the locking mechanism to allow removal of handle 1 12.

[0065] FIG. 3 is a view of dynamic distractor 100 opened for distracting two surfaces of the muscular-skeletal system in accordance with an exemplary embodiment. A lift mechanism 302 comprises a scissor mechanism 304 for raising and lowering upper support structure 202 and lower support structure 204. In one embodiment, scissor mechanism 304 comprises more than one support structure each having a pivot. Scissor mechanism 304 is operatively coupled to an interior surface of upper support structure 202 and an interior surface of lower support structure 204. The structural beams are pinned to allow pivoting around the axis of attachment. The remaining beam-ends rest on the interior surfaces of either the upper and lower support structures 202 and 204. The beam-ends not fastened to the interior surfaces support upper and lower support structures 202 and 204 under load. Threaded rod 212 is operatively coupled between the beam-ends of scissor mechanism 304 corresponding to lower support structure 204. Rotating rod 212 can increase or decrease distance between beam ends of the scissor mechanism 204.

[0066] A rod 306 can be coupled to opening 1 14 of handle 1 12. The rod 306 can be used to reduce the torque needed to rotate threaded rod 212 in either direction under load. Increasing a distance between beam-ends of scissor mechanism 304 reduces the gap between superior surface 102 and inferior surface 206 as the two or more beams pivot around a centrally located axis. Conversely, decreasing a distance between beam-ends of scissor mechanism 304 increases the gap between superior surface 102 and inferior surface 206.

[0067] FIG. 4 is an anterior view of a dynamic distractor 100 placed in a knee joint in accordance with an exemplary embodiment. In the non-limiting example, a distal end of a femur 402 is shown having a femoral implant 410. The femoral implant 410 has artificial condyles that contact sensors 108 and 1 10. The proximal end of a tibia 404 has been initially shaped for receiving a tibial implant. As is well known by one skilled in the art, a complete knee implant comprises the tibial implant, the femoral implant, and an insert that includes bearing surfaces that mate with the artificial condyle surfaces of the femoral implant. In one embodiment, dynamic distractor (100) includes an adjustable handle 1 12 that aids in the insertion of the spacer portion into a joint region of the muscular-skeletal system. For example, the spacer portion of dynamic distractor 100 is inserted into the knee joint using handle 1 12 but then rotated away from the patellar tendon, collapsed into the trail, or removed to allow the reduction of the patella to depict loads on the instrument. The thickness or height of the three components is contemplated for the bone surface preparation when using dynamic distractor 100. In one embodiment, the combined thickness of the femoral implant, final insert, and tibial implant is approximately 20 millimeters thick. Adjustments to the prepared bone surfaces and thickness of the insert are made during surgery using data provided by dynamic distractor 100 to ensure correct loading, balance, and alignment.

[0068] Sensors 108 and 1 10 include circuitry for communication with a processing unit 406. In one embodiment, data is sent wirelessly using a radio frequency communication standard such as Bluetooth, UWB, or Zigbee. The data can be encrypted to securely transmit the patient information and maintain patient privacy. In one embodiment, external processing unit 406 is in a notebook computer, personal computer, or custom equipment. For illustration purposes, external processing unit 406 is shown in a notebook computer that includes software and a GUI designed for the surgical application. The notebook computer has a display 408 that can be used by the medical staff during the operation to display real time measurement from dynamic distractor 100. The notebook computer is typically placed outside the surgical zone but within viewing range of the surgeon.

[0069] A substantial benefit of dynamic distractor 100 is in performing soft tissue release both in extension and in flexion. In extension, dynamic distractor 100 can be set to a height corresponding to an insert size. In one embodiment, manufacturers of an implantable joint will provide specifications for load, balance, and alignment once sufficient clinical data has been generated. The surgeon can also manipulate the leg to subjectively gauge the loading on the joint. The surgeon can adjust dynamic distractor 100 to increase or decrease the height or gap corresponding to a different thickness insert size until a desired loading is achieved. A substantial imbalance corresponds to a differential loading measured by sensors 108 and 1 10 outside a predetermined range. The loading measured by sensors 108 and 1 10 should be approximately equal in each compartment. The data provided by sensors 108 and 1 10 can be used to provide a solution to the surgeon. For example, data from sensors 108 and 1 10 is sent wirelessly to processing unit 406. The data indicates a substantial differential pressure between measurements from sensors 108 and 1 10 (e.g. imbalance). In one embodiment, the data can be processed and displayed on display 408 with suggestions for the removal of material from the tibial surface to reduce the differential reading. The suggestion can include where material should be removed and how much material is removed from the tibial surface. Alternatively, the assessment of the loading and differential between compartments can indicate that soft tissue release is sufficient to bring the joint within predetermined ranges for absolute load and balance.

[0070] A further benefit of dynamic distractor 100 is in soft tissue release to modify loading measured by sensors 108 and 1 10 and the differential (e.g. balance) between the measured values in each compartment. Dynamic distractor 100 remains in place while soft tissue release is being performed allowing for real time measurement and modification to occur. The feedback to the surgeon is immediate as the soft tissue cuts are made. Two issues are resolved by dynamic distractor 100. An open area formed between the interior surfaces of upper support structure 202 and lower support structure 204 under distraction provides surgical access. In most cases, the gap is sufficient to allow a scalpel or blade access to the lateral or medial ligaments for soft tissue release in the gap or peripheral to dynamic distractor 100. In general, soft tissue release requires anterior access to the joint space. Handle 1 12 of dynamic distractor 100 can be removed providing further anterior access to the joint. Alternatively, handle 1 12 is hinged or includes a joint allowing it to be positioned away from the surgical area. Thus, dynamic distractor 100 enables soft tissue release by the surgeon to adjust the absolute loading measured by sensors 108 and 1 10 in each compartment to be within a predetermined range and to adjust the difference in compartment loadings within a predetermined range without removing the device.

[0071] FIG. 5 is a lateral view of dynamic distractor 100 in a knee joint positioned in flexion in accordance with an exemplary embodiment. In a non- limiting example, load and balance measurements are performed using dynamic distractor 100 with the leg in at least two positions (e.g. the leg in extension and the leg in flexion). For example, measurements are taken in extension as disclosed hereinabove and in flexion with the leg positioned having femur 402 forming a 90 degree angle to tibia 404. In one embodiment, accelerometers in sensors 108 and 1 10 are used to determine relative positioning of the femur and tibia to one another. Under user control, measurements are taken at several points over the range of motion with dynamic distractor 100 in place thereby substantially simplifying a data collection process. Measurements over the range of motion can be taken when the femoral implant has been installed or if the distal femur has not been modified. Alternatively, dynamic distractor 100 can be reduced in height by rotating handle 1 12 until there is sufficient room to move the leg to a new position and then increasing the height of distractor 100 to create the appropriate gap.

[0072] A drop alignment rod 502 is placed through opening 114 of handle 1 12. Drop alignment rod 502 is a visual aid for the surgeon to ensure that the leg is aligned adequately when the load and balance measurements are taken. Drop alignment rod 502 is used in conjunction with a knowledge of the leg mechanical axis or with markers placed on the patient to check alignment. The surgeon aligns alignment rod 502 to the leg mechanical axis and makes a subjective determination that the leg is correctly positioned. The surgeon can increase accuracy by pre-identifying points on the mechanical axis. The surgeon has the option of making adjustments if drop alignment rod 502 indicates a potential positional error. Drop alignment rod 502 can be tapered having a section with a greater width than opening 1 14 to retain it in place and prevent it from falling through. Other embodiments to retain drop alignment rod 502 can also be used.

[0073] Alternatively, drop alignment rod 502 can be a smart alignment aid for the surgeon that incorporates electronics similar to that described in FIG. 2. In general, drop alignment rod includes sensors to allow depiction of the mechanical axis. For example, drop alignment rod 502 can incorporate sensors to identify position in three-dimensional space. The electronics would allow drop alignment rod 502 to communicate with pre-operative defined locations or locations that are identified at the time of surgery using locator electronics. The drop rod can house light emitters to depict an axis as will be discussed in more detail hereinbelow. The electronics can include communication to external processing unit 406 with a graphic user interface that has the mechanical axis loaded therein.

[0074] FIG. 6 is a lateral view of a dynamic distractor 100 in a knee joint coupled to a cutting block 602 in accordance with an exemplary embodiment. In general, the surgeon utilizes surgical tools to obtain appropriate bony cuts to the skeletal system. The surgical tools are often mechanical devices used to achieve gross alignment of the skeletal system prior to or during an implant surgery. In the knee example, mechanical alignment aids are often used during orthopedic surgery to check alignment of the bony cuts of the femur and tibia to the mechanical axis of the leg. The mechanical alignment aids are not integrated together, take time to deploy, and have limited accuracy. Dynamic distractor 100 in concert with cutting block 602 is an integrated system for achieving alignment that can greatly reduce set up time thereby minimizing stress on the patient.

[0075] As illustrated, the leg is in flexion having a relational position of 90 degrees between femur 402 and tibia 404. A femoral rod 608 is coupled through the intermedullary canal of femur 402. A cutting block 602 is attached to the femoral rod 608 for shaping a portion of the surface of the distal end of femur 402 for receiving a femoral implant. Knee replacement surgery entails cutting bone a certain thickness and implanting a prosthesis to allow pain relief and motion. During the surgery, instruments are used to assist the surgeon in performing the surgical steps appropriately. Dynamic distractor 100 aids the surgeon by allowing quantitative measurement of the gap and parameter measurement during all stages of the procedure. For the knee, the data can supplement a surgeon's "feel" by providing data on absolute loading in each compartment, the load differential between compartments, positional information, and alignment information.

[0076] The portion of the surface of the distal end of femur 402 in contact with dynamic distractor 100 is shaped in a subsequent step. In a non-limiting example, the portion of the condyles in contact with superior surface 102, sensor 108, and sensor 110 are the natural condyles of the femur. The portion of the distal end of femur 402 being shaped corresponds to the condyle portion that would be in contact with the final spacer while the leg is in extension and partially through the range of motion. In at least one exemplary embodiment, an uprod 604 of dynamic distractor 100 couples to cutting block 602. Uprod 604 aids in the alignment of the cutting block 602 to dynamic distractor 100 and tibia 404. Uprod 604 further stabilizes cutting block 602 to prevent movement as the distal end of femur 402 is shaped.

[0077] In one embodiment, handle 1 12 is removed and an uprod 604 is attached to threaded rod 212. The uprod 604 can include a hinge that positions rod 604 vertically to mate with cutting block 602. Alternatively, handle 1 12 can include a hinge. In this example, handle 1 12 is uprod 604 and is inserted into cutting block 602. Furthermore, uprod 604 can be fastened or coupled to an opening or feature in handle 1 12 to couple to cutting block 602. In general, uprod 604 is placed at a right angle to the inferior surface of lower support structure 204 of dynamic distractor 100. In a prior step, the leg alignment can be checked to ensure it is within a predetermined range of the mechanical axis. In one embodiment, uprod 604 aligns approximately to the mechanical axis to secure cutting block 602 in an appropriate geometric orientation. Cutting block 602 includes a channel 606 for receiving uprod 604. Uprod 604 can be adjustable in length that simplifies insertion. As previously mentioned, uprod 604 is attached to dynamic distractor 100 to align with the mechanical axis of the leg corresponding to tibia 404. Fitted in the opening and into channel 606, uprod 604 maintains a positional relationship between cutting block 602, dynamic spacer block 100, femur 402, and tibia 404. More specifically, the proximal surface of tibia 404 is aligned to the mechanical axis thereby fixing the position of femur 402 and cutting block 602 in a similar fixed geometric relational position. Thus, the distal end of femur 402 is cut having surfaces parallel to the proximal tibial surface by coupling dynamic distractor 100 to cutting block 602 through uprod 604.

[0078] FIG. 7 is an anterior view of a cutting block 602 coupled to dynamic distractor 100 in accordance with an exemplary embodiment. Cutting block 602 is attached to the distal end of femur 402. Femoral rod 608 extends through cutting block 602 into the intermedullary canal. Uprod 604 is shown extending vertically into channel 606 of cutting block 602. In combination, femoral rod 608 and uprod 604 prevent movement and maintain alignment of the cutting block to the leg mechanical axis. As shown, cutting block 602 is illustrated as rectangular in shape. Cutting block 602 is shaped to form a predetermined bone shape on the distal end of femur 402 for receiving a femoral implant. Thus, the shape of cutting block 602 can vary significantly from that shown depending on the implant. The size of the cutting block 602 corresponds to the distal end size and the femoral implant selected by the surgeon. The surgeon uses a bone saw to remove portions of the distal end of femur 402 in conjunction with cutting block 602. In general, the cutting block 602 acts as a template to guide the bone saw and to cut the distal end of the femur in a predetermined geometric shape. As disclosed previously in the example, the portion of the distal end of femur 404 that is shaped corresponds to the contact portion of the condyles when the leg is in full extension and partially in flexion (e.g. < 90 degrees). As mentioned previously, the portion of the distal end of femur 402 in contact the superior surface 102 of dynamic distractor 100 is shaped in a subsequent step.

[0079] FIG. 8 is an illustration of dynamic distractor 100 including alignment in accordance with an exemplary embodiment. Dynamic distractor 100 includes one or more recesses 802 in a handle 804 for receiving an alignment aid to align a leg along the mechanical axis. In one embodiment, handle 804 can be handle 1 12 that includes recesses 802. Alternatively, handle 804 is a separate handle for dynamic distractor 100. Prior to checking alignment, handle 1 12 is removed from dynamic distractor 100. Handle 804 is coupled to threaded rod 212.

[0080] Initial bony cuts are made in alignment with the mechanical axis of the leg. In the knee example, the alignment aid is used to check that the femur and the tibia are correctly oriented prior to cutting. The surfaces of the bones are cut in alignment to the mechanical axis using a jig. Thus, the cut surfaces on the distal end of the femur and the proximal end of the tibia are aligned and can be used as a reference surfaces during the procedure. Alternatively, the alignment aid can be used to verify alignment throughout the procedure. Recesses 802 can be thru-holes in handle 804. In a non-limiting example, the alignment aid is one or more lasers 808. Lasers 808 are used to point along the mechanical axis of the leg. In one embodiment, lasers 808 are used to check alignment of the leg. A first laser is used to point in the direction of the hip joint. A second laser is used to point towards the ankle. In one embodiment, the first and second lasers are integrated into a single body. Handle 804 further comprises a hinge 806 to change the angle at which lasers 808 are directed. The housing of lasers 808 includes a power source such as a battery to generate the monochromatic light beam. The housing fits within one of recesses 802 or a thru-hole. Lasers 808 can be a disposable item that is discarded after the surgery is completed.

[0081] FIG. 9 is a side view of a leg in extension with dynamic distractor 100 in the knee joint region in accordance with an exemplary embodiment. The mechanical axis of the leg is approximately a straight line from the center of the femoral head through the knee joint and extending to the middle of the ankle joint. In a correctly aligned knee joint, the mechanical axis will pass approximately through the center of the knee joint. Alignment can be checked when dynamic distractor 100 is positioned in the knee joint region. As illustrated, the leg is in extension with handle 804 extending vertically from the knee joint region. In one embodiment, a target 902 is placed in an ankle or toe region of the foot in a path corresponding to center of the ankle on the mechanical axis of the leg. Similarly, a target 904 is placed in a path corresponding to the center of the head of the femur on the mechanical axis of the leg. Targets 902 are placed at a height similar to that of lasers 808. Lasers 808 are installed in the handle with one pointing in the direction of the hip joint and another pointing in the direction of the ankle joint. From the top view, lasers 808 send out a beam of light from a position that corresponds to the center of the knee. In one embodiment, the direction of the beam from lasers 808 is directed perpendicular to a plane of the prepared surface of the proximal end of the tibia.

[0082] Lasers 808 are directed perpendicular to the inferior surface of dynamic distractor 100. The placement of dynamic distractor 100 on the prepared tibial surface is such that handle 804 extends vertically at a point corresponding to the center of the knee joint. The leg is aligned correctly when the beams from lasers 808 hit the target at the points corresponding to the center of the head of the femur and the center of the ankle. Lasers 808 are positioned to align with the center of the knee joint. The surgeon can make adjustments to the bone surfaces or utilize soft tissue release to achieve alignment with the leg mechanical axis when lasers 808 are misaligned to the target. The system can be used to give a subjective or a measured determination on leg alignment in relation to a vargus or valgus alignment. The direction of misalignment in viewing targets 902 and 904 will dictate the type of correction and how much correction needs to be made. In an alternate embodiment, lasers 808 can be aimed such that the beam is viewable along the leg in a region by the center of the femoral head and the center of the angle. The surgeon can use this as a subjective visual gauge to determine if the leg is in alignment to the mechanical axis and respond appropriately, depending on what is viewed.

[0083] FIG. 10 is a top view of a leg in extension with dynamic distractor 100 in the knee joint area in accordance with an exemplary embodiment. Dynamic distractor 100 can measure spacing between the distal end of the femur and the tibia, loading in each compartment, and differential loading between compartments. The data can be sent to a processing unit and display as disclosed hereinabove. As mentioned previously, the mechanical axis of the leg corresponds to a straight line from the center of the ankle, through the center of the knee, and the center of the femoral head. Targets 902 and 904 are respectively located overlying the mechanical axis in an area local to the ankle and the hip regions. Targets 902 and 904 can include a fixture such as a strap, brace, or jig to hold the targets temporarily along the mechanical axis. Lasers 808 are enabled and placed in handle 804. The figure illustrates that targets 902 and 904 are on approximately the same plane as beams emitted by lasers 808 such that the beams impinge on a target unless grossly misaligned. Targets 902 and 904 can include calibration markings to indicate a measure of the misalignment. Alternatively, handle 804 is hinged allowing adjustment of the angle at which the beam from lasers 808 is directed. The direction of the lasers 808 corresponds to the plane of the bone cuts for the implant and the balance of the joint. Thus, the surgeon using a single device has both quantitative and subjective data relating to alignment to the mechanical axis, loading, balance, leg position, and gap measurement that allows gross/fine tuning during surgery that results in more consistent orthopedic outcomes.

[0084] FIG. 11 is an illustration of a system 1 100 for measuring one or more parameters of a biological life form in accordance with an exemplary embodiment. In a non-limiting example, the system provides real time measurement capability to a surgeon of one or more parameters needed to assess a muscular-skeletal system. System 1 100 comprises a plurality of spacer blocks 1 102, a distractor 1 104, sensors 1 106, targets 1 1 10, lasers 1 1 14, a charger 1 1 16, a receiver 1 1 18, a reader 1 120, a processing unit 1 122, a display 1 124 a drop rod 1 126, an uprod 1 128, a cutting block 1 130, a handle 1 132, a dynamic data repository and registry 1134. The system is adaptable to provide accurate measurements of parameters such as distance, weight, strain, pressure, wear, vibration, viscosity, and density to name but a few. In one embodiment, system 1 100 is used in orthopedic surgery and more specifically to provide intra-operative measurement during joint implant surgery. System 1 100 is adapted for orthopedic surgery and more specifically for knee surgery to illustrate operation of the system.

[0085] In general, system 1 100 provides alignment and parameter measurement system for providing quantitative measurement of the muscular- skeletal system. In one embodiment, system 1 100 is integrated with tools commonly used in orthopedics to reduce an adoption cycle to utilize new technology. System 1 100 replaces standalone equipment or dedicated equipment that is used only for a small number of procedures that justifies the extra time and set up required to use this type of equipment. Furthermore, it is well known, that dedicated equipment can cost hundreds of thousands or millions of dollars for a single device. Many hospitals and other healthcare facilities cannot afford the high capital cost of these types of systems. Moreover, specialized equipment such as robotic systems or alignment systems for orthopedic surgery typically has a large footprint. The large footprint creates space and cost issues. The equipment must be stored, set up, calibrated, placed in the operating room, and then removed.

[0086] Conversely, measurement and alignment components of system 1 100 are low cost disposables that make the measurement technology more accessible to the general public. There is no significant capital investment required to use the system. Moreover, payback begins immediately with use in providing quantitative information related to procedures thereby allowing analysis of outcomes based how the parameters being measured affect the procedure being measured. The data is used to initiate predetermined specifications for the procedure that can be measured and adjusted during the course of the procedure thereby optimizing the outcomes and reducing revisions. As mentioned previously, system 1 100 can be used or integrated with tools that the majority of orthopedic surgeons have substantial experience or familiarity using on a regular basis. In one embodiment, sensors 1 106 are placed in a spacer that separates two surfaces of the muscular-skeletal system. In a non-limiting example, the spacer can be spacer blocks 1 102 or distractor 1 104. A measurement of the parameter is taken after the spacer is inserted between at least two surfaces of the muscular-skeletal system. Sensors 1 106 are in communication with processing unit 1122. In one embodiment, the processing unit 1 122 is outside the sterile field and includes display 1 124 and a GUI to provide the data in real time to the surgeon. Thus, the learning cycle can be very short to provide real time quantitative feedback to the surgeon as well as storing the data for subsequent use.

[0087] In a non-limiting example a spacer separates two surfaces of the muscular-skeletal system. The spacer has an inferior surface and a superior surface that contact the two surfaces. The spacer can have a fixed height or can have a variable height. The fixed height spacer is known as spacer blocks 1 102. Each spacer block 1 102 has a different thickness. The variable height spacer is known as the distractor 1 104. The surface area of spacer blocks 1 102 and distractor 1 104 that couple to the surfaces of the muscular-skeletal system can also be provided in different sizes. The handle 1 132 extends from the spacer and typically resides outside or beyond the two surface regions. The handle 1 132 is used to direct the spacer between the two surfaces. In one embodiment, the handle 1 132 operatively couples to a lift mechanism of the distractor 1 104 to increase and decrease a gap between the superior and inferior surfaces of the spacer. The spacer and handle 1 132 is part of system 1 10O to measure alignment of the muscular-skeletal system. In one embodiment, at least one of the surfaces of the muscular-skeletal system that contacts the spacer has an optimal alignment to a mechanical axis of the muscular-skeletal system. The system measures the surface to mechanical axis alignment. In a non-limiting example, the misalignment can be corrected by a surgeon when the surface is misaligned to the mechanical axis outside a predetermined range as disclosed below.

[0088] Knee replacement surgery entails cutting bone having a predetermined spacing and implanting a prosthesis to allow pain relief and motion. During the surgery, instruments are used to assist the surgeon in performing the surgical steps appropriately. The majority of surgeons continue to use passive spacers to aid in defining the gaps between the cut bones. The thickness of the final insert is selected after placing one or more trial inserts in the artificial joint implant. The determination of whether the implanted components are correctly installed is still to a large extent by "feel" of the surgeon through movement of the leg. In general, spacer blocks 1 102 and distractor 1 104 of system 1 100 is a spacer having an inferior and superior surface that separate at least two surfaces of the muscular-skeletal system. In the knee example, the inferior and superior surfaces are inserted between the femur and tibia of the knee. At least one of the inferior or superior surfaces of spacer blocks 1 102 and distractor 1 104 have a cavity or recess for receiving sensors 1 106. In one embodiment, the cavity is on the superior surface of spacer blocks 1 102 and distractor 1 104. A gap between the surfaces of distractor 1 104 is adjustable as described hereinabove. Tray 1 108 includes multiple spacer blocks 1 102 each having a different thickness. Thus, spacer blocks 1 102 and distractor 1 104 provide the surgeon with more than one option to measure spacing, alignment, and loading during the procedure. A benefit of the system is the familiarity that the surgeon will have with using similar type devices thereby reducing the learning curve to utilize system 1 100. Furthermore, system 1 100 can comprise spacer blocks 1102 and distractor 1 104 having spacer blocks having different sized superior and inferior surface areas to more readily accommodate different bone shapes and sizes.

[0089] In general, a rectangle is formed by the bony cuts during surgery. The imaginary rectangle is formed between the cut distal end of a femur and the cut proximal end of tibia in extension and in conjunction with the mechanical axis of the lower leg. The prepared surfaces of the femur and tibia are shaped to respectively receive a femoral implant and a tibial implant. The femoral and tibial surfaces are parallel to one another when the leg is in extension and in flexion at 90 degrees. A predetermined width of the rectangle is the spacing between the planar surface cuts on femur and tibia. The predetermined width corresponds to the thickness of the combined orthopedic implant device comprising the femoral implant, an insert, and the tibial implant. A target thickness for the initial cuts is typically on the order of twenty millimeters. The insert is inserted between the installed femoral implant and the tibial implant. In a full knee implant the insert has two bearing surfaces that are shaped to receive the condyle surfaces of the femoral implant.

[0090] In at least one exemplary embodiment, sensors 1 106 can measure load and position. Sensors 1 106 are placed in a charger 1 1 16 prior to the implant surgery being performed. Charger 1 1 16 provides a charge to an internal power source within sensors 1 106 that will sustain sensor measurement and data transmission throughout the surgery. Charger 1 1 16 can fully charge sensor 1106 or be used as a precautionary measure to insure the temporary power storage is holding sufficient charge. Charger 1 1 16 can be charge via a wireless connection through a sterilized packaging. Sensors 1 106 are in communication with processing unit 1 122. Sensors 1 106 include a transmitter for sending data. Processing unit 1 122 can be logic circuitry, a digital signal processor, microcontroller, microprocessor, or part of a system having computing capability. As shown, processing unit 1 122 is a notebook computer having a display 1 124. The communication between sensors 1 106 and processing unit 1 122 can be wired or wireless. In one embodiment, receiver 1 1 18 is coupled to processing for wireless communication. A carrier signal for data transmitted from sensors 1 106 can be radio frequency, infrared, optical, acoustic, and microwave to name but a few. In a non-limiting example, receiver 1 1 18 receives data via a radio frequency signal in a short range unlicensed band sufficient for transmission within the size of an operating room. Information from processing unit 1 122 can be sent through the internet to dynamic data repository and registry 1 134 for long-term storage. The dynamic data repository and registry 1 134 will be discussed in greater detail hereinbelow. In one embodiment, the data is stored in a server 1 136 or as part of a larger database.

[0091] The surgeon uses system 1 100 to aid in the preparation of bone surfaces, to measure loading, to measure balance, check alignment, and tune the knee joint prior to a final insert being installed. A reader 1 120 is used to scan in information prior to or during the surgery. In one embodiment, the reader 1 120 can be wired or wirelessly coupled to the processing unit 1 122. Processing unit 1 122 can process the information, display it on display 1 124 for use during a procedure, and store it in memory or a database for long-term use. For example, information on components used in the surgery such as the artificial knee components or components of system 1 100 can be converted to an electronic digital form using reader 1 120 during the procedure. Similarly, patient information or procedural information can also be scanned in, input manually, or captured by other means to processing unit 1 122.

[0092] The leg is placed in extension and the knee joint is exposed by incision. In one embodiment, the surgeon prepares the proximal end of the tibia. The prepared tibial surface is typically at a 90-degree angle to the mechanical axis of the leg. Targets 1 1 10 are placed overlying the mechanical axis near the ankle and hip joint. The surgeon can select one of the spacer blocks 1 102 or dynamic distractor 1 104 for insertion in the joint region. The selected spacer block has a predetermined thickness that is imprinted on the spacer block or can be displayed on display 1 124 by scanning the information. Alternatively, distractor 1 104 is distracted by the surgeon within the joint region. The amount of distraction can be read off of distractor 1 104 or can be displayed on display 1 124.

[0093] In a non-limiting example of aligning two surfaces of the muscular- skeletal system, alignment of the leg to the mechanical axis is measured or a subjective check can be performed by the surgeon using an alignment aid. At least one component of the alignment aid is disposable. The alignment aid comprises lasers 1 1 14 in the handle 1 1 12 of the selected spacer block or a handle 1 132 of distractor 1 104 with the leg in extension. The alignment aid further includes targets 1 1 10. Targets 1 1 10, lasers 1 1 14, or both can be disposable. Accelerometers in sensors 1 106 provide positional information of the tibia in relation to the femur. For example, display 1 124 will indicate that the angle between the tibia and femur is 180 degrees when the leg is in extension. The beam from lasers 1 1 14 hit targets 1 1 10 and provides a measurement of the position of the tibia in relation to the femur that is compared to the mechanical axis of the leg. In one embodiment, lasers 1 1 14 are centrally located above the knee joint overlying the mechanical axis of the leg. The beam from lasers 1 1 14 is directed perpendicular to the plane of the surface of the tibia. The beam from lasers 1 1 14 will align and overlie the mechanical axis if the surface of the tibia is the perpendicular to the mechanical axis. The beam from lasers 1 1 14 would hit targets 1 1 10 at a point that indicates alignment with the mechanical axis. A valgus or vargus reading can be read where the beam hits the calibrated markings of targets 1 1 10 if the leg is not aligned. The surgeon can then make an adjustment to bring the leg into closer alignment to the mechanical axis if deemed necessary. Jigs or cutting blocks can also be used in conjunction with lasers 1 1 14 and targets 1 1 10 to check alignment prior to shaping. The jigs or cutting blocks are used to shape the bone for receiving an implant. The distal end of femur and the proximal end of tibia are shaped for receiving orthopedic joint implants. In a further embodiment, sensors can be attached to the cutting jigs or devices to aid the surgeon in optimizing the depth and angles of their cuts.

[0094] Sensors 1 106 measure the loading in each compartment for the depth or thickness of the selected spacer block or the distracted gap generated by distractor 1 104. In one embodiment, the loading measurements are taken after the initial bone cuts are determined to be within a predetermined range of alignment with the mechanical axis. The load measurement in each compartment is either high, within an acceptable predetermined range, or low. A load measurement above a predetermined range can be adjusted by removing bone material, selecting a thinner spacer block, adjusting the gap of distractor 1 104, or by soft tissue release. In general, the gap between the femur and tibia at which the measurement taken corresponds to a final insert thickness. In one embodiment, the gap is selected to result in a load measurement on the high side of the predetermined range to allow for fine-tuning through soft tissue release. Conversely, a load measurement below the predetermined range can be increased using the next thicker spacer block or by increasing the gap of distractor 1 104. Data from sensors 1 106 is transmitted to processing unit 1 122. Processing unit 1 122 processes the data and displays the information on display 1 124 for use by the surgeon to aid in fine-tuning. Display 1 124 would further provide positional information of the femur and tibia. The absolute loading in each compartment is measured and displayed on display 1 124. As is known by one skilled in the art, the gap created by the bone cuts accommodates the combined thickness of the femoral implant, the tibial implant, and the insert. The gap using spacer blocks 1 102 or distractor 1 104 takes into account the combined thickness of the implant components. In a non-limiting example, the gap is chosen based on the availability of different thicknesses of the final insert. Thus, the loading on the final or permanent insert placed in the joint will measure within the predetermined range as prepared by using system 1 100.

[0095] Balance is a comparison of the load measurement of each condyle surface. In general, balance correction is performed when the measurements exceed a predetermined difference value. Soft tissue balancing is achieved by loosening ligaments on the side of the compartment that measures a higher loading. In one embodiment, system 1 100 allows the surgeon to read the loading measurement for each compartment on one or more displays on spacer blocks 1 102 or distractor 1 104. Another factor is that the difference in loading can be due to surface preparation of the bony cuts for either femoral implant or the tibial implant. If the differential is substantial, the surgeon has the option of removing bone on either surface underlying the implant to reduce the loading difference.

[0096] In one embodiment, the absolute load adjustments and balance adjustments are performed by soft tissue release in response to the assessment of each compartment. Load and balance adjustment is achieved with the selected spacer block or distractoM 104 in the knee joint. Spacer blocks 1 102 and distractor 1 104 have a gap to provide peripheral access between the superior and inferior surfaces of the device thereby giving the surgeon access to perform soft tissue release to either compartment with real time load measurement shown on display 1 124. In at least one exemplary embodiment, handles 1 1 12 of spacer blocks 1 102 or handle 1 132 of distractor 1 104 can be removed or positioned. Handles 1 1 12 or handle 1 132 can be positioned away from the surgical area or removed allowing the surgeon access to perform soft tissue release. The soft tissue release is performed to each compartment to adjust the absolute loading within the predetermined range and further adjustment can be performed to reduce the differential loading between the compartments to within a predetermined differential range. Consequently, the surgical outcome is a function of system 1 100 as complemented with the surgeon's abilities but not so highly dependent alone on the surgeon's skill. The device captures the "feel" of how an implanted device should properly operate to improve precision and minimize variation including haptic and visual cues.

[0097] A similar process is applied with the lower leg in flexion with tibia forming a 90-degree angle with the femur. In one embodiment, one or more bone cuts are made to the distal end of femur for receiving the femoral implant. The preparation of the femur corresponds to the leg in extension. As disclosed above, the selected spacer block or distractor 1 104 can be coupled using an uprod from handle 1 1 12 or handle 1 132 to cutting block 1 130 to aid in alignment and stability. In particular, the surface of the distal end of femur is cut parallel to the prepared surface of the tibia with the leg in flexion. The bone cut to the femur yields an imaginary rectangle formed with the parallel surfaces of femur and tibia when the leg is in extension. It should be noted that a portion of the femoral condyle is in contact with the selected spacer block or distractor 1 104 with the leg in flexion and this region is not prepared at this time. In a subsequent step, the remaining surface of the distal end of the femur is prepared. The width of the gap in extension and in flexion between the cut distal end of the femur and the prepared tibia surface corresponds to the thickness of the combined orthopedic implant device comprising the femoral implant, final insert, the tibial implant. Ideally, the measured the gap under equal loading in flexion (e.g. the tibia forms a 90 degree angle with the femur) and extension is similar or equal. The prepared femoral surfaces and the prepared tibial surfaces are parallel throughout the range of motion and perpendicular to the mechanical axis of the leg.

[0098] Load measurements are made with the leg in flexion and the selected spacer block or distractor 1 104 between the distal end of the femur and the tibial surface. In a non-limiting example, the measurements as described above should be similar to the measurements made in extension. Adjustments to the load value and the balance between compartments can be made by soft tissue release, or femoral component rotation in flexion with the selected spacer block or distractor 1 104 in place. Alternatively, the femoral implant can be seated on the distal end of the femur and measurements taken. Adjustments can be made with the femoral implant in place. Furthermore, a gap generated by distractor 1 104 can be adjusted to accommodate differences due to the femoral implant if required.

[0099] The leg with the selected spacer block or distractor 1 104 can be taken through a complete range of motion. The loading in each compartment can be monitored on displayi 124 and processed by processing unit 1 122 over the range of motion. Processing unit can compare different points in the range of motion to the predetermined load range and the predetermined differential load range. Should an out of range/value condition occur, the surgeon can view and note the position of the femur and tibia position on display 1 124 and take steps to bring the implant within specification. The surgeon can complete the implant surgery having knowledge that both qualitative and quantitative information was used during the procedure to ensure correct installation. In one embodiment, sensors 1 106, disposable targets 1 1 10, and lasers 11 14 are disposed of upon completion of the surgery.

[00100] For example, the sensors will enable the surgeon to measure joint loading while utilizing soft tissue tensioning to adjust balance and maximize stability of an implanted joint. Similarly, measured data in conjunction with positioning can be collected before and during surgery to aid the surgeon in ensuring that, the implanted device has an equivalent geometry and range of motion.

[00101 ] FIG. 12 Element 1340 of FIG. 12 depicts an exemplary diagrammatic representation of a machine in the form of a computer system 420Θ within which a set of instructions, when executed, may cause the machine to perform any one or more of the methodologies discussed above. In some embodiments, the machine operates as a standalone device. In some embodiments, the machine may be connected (e.g., using a network) to other machines. In a networked deployment, the machine may operate in the capacity of a server or a client user machine in server-client user network environment, or as a peer machine in a peer-to-peer (or distributed) network environment.

[00102] The machine may comprise a server computer, a client user computer, a personal computer (PC), a tablet PC, a laptop computer, a desktop computer, a control system, a network router, switch or bridge, or any machine capable of executing a set of instructions (sequential or otherwise) that specify actions to be taken by that machine. It will be understood that a device of the present disclosure includes broadly any electronic device that provides voice, video or data communication. Further, while a single machine is illustrated, the term "machine" shall also be taken to include any collection of machines that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein. [00103] The computer system +200 may include a processor 4-202 (e.g., a central processing unit (CPU), a graphics processing unit (GPU, or both), a main memory 4-204 and a static memory +20β, which communicate with each other via a bus +QOS. The computer system +200 may further include a video display unit +24-0 (e.g., a liquid crystal display (LCD), a flat panel, a solid-state display, or a cathode ray tube (CRT)). The computer system +200 may include an input device +2+2 (e.g., a keyboard), a cursor control device +2+4 (e.g., a mouse), a disk drive unit +2+§, a signal generation device +24-8 (e.g., a speaker or remote control) and a network interface device +220.

[00104] The disk drive unit +2+§ may include a machine-readable medium +222 on which is stored one or more sets of instructions (e.g., software +224) embodying any one or more of the methodologies or functions described herein, including those methods illustrated above. The instructions +224 may also reside, completely or at least partially, within the main memory +204, the static memory +2θβ, and/or within the processor +202 during execution thereof by the computer system +200. The main memory +204 and the processor +202 also may constitute machine-readable media.

[00105] Dedicated hardware implementations including, but not limited to, application specific integrated circuits, programmable logic arrays and other hardware devices can likewise be constructed to implement the methods described herein. Applications that may include the apparatus and systems of various embodiments broadly include a variety of electronic and computer systems. Some embodiments implement functions in two or more specific interconnected hardware modules or devices with related control and data signals communicated between and through the modules, or as portions of an application-specific integrated circuit. Thus, the example system is applicable to software, firmware, and hardware implementations.

[00106] In accordance with various embodiments of the present disclosure, the methods described herein are intended for operation as software programs running on a computer processor. Furthermore, software implementations can include, but not limited to, distributed processing or component/object distributed processing, parallel processing, or virtual machine processing can also be constructed to implement the methods described herein.

[00107] The present disclosure contemplates a machine readable medium containing instructions 4-224, or that which receives and executes instructions +224 from a propagated signal so that a device connected to a network environment +226 can send or receive voice, video or data, and to communicate over the network +226 using the instructions +224. The instructions +224 may further be transmitted or received over a network +226 via the network interface device +22Θ.

[00108] While the machine-readable medium +222 is shown in an example embodiment to be a single medium, the term "machine-readable medium" should be taken to include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) that store the one or more sets of instructions. The term "machine-readable medium" shall also be taken to include any medium that is capable of storing, encoding or carrying a set of instructions for execution by the machine and that cause the machine to perform any one or more of the methodologies of the present disclosure.

[00109] The term "machine-readable medium" shall accordingly be taken to include, but not be limited to: solid-state memories such as a memory card or other package that houses one or more read-only (non-volatile) memories, random access memories, or other re-writable (volatile) memories; magneto- optical or optical medium such as a disk or tape; and carrier wave signals such as a signal embodying computer instructions in a transmission medium; and/or a digital file attachment to e-mail or other self-contained information archive or set of archives is considered a distribution medium equivalent to a tangible storage medium. Accordingly, the disclosure is considered to include any one or more of a machine-readable medium or a distribution medium, as listed herein and including art-recognized equivalents and successor media, in which the software implementations herein are stored. [00110] Although the present specification describes components and functions implemented in the embodiments with reference to particular standards and protocols, the disclosure is not limited to such standards and protocols. Each of the standards for Internet and other packet switched network transmission (e.g., TCP/IP, UDP/IP, HTML, HTTP) represent examples of the state of the art. Such standards are periodically superseded by faster or more efficient equivalents having essentially the same functions. Accordingly, replacement standards and protocols having the same functions are considered equivalents.

[00111] The illustrations of embodiments described herein are intended to provide a general understanding of the structure of various embodiments, and they are not intended to serve as a complete description of all the elements and features of apparatus and systems that might make use of the structures described herein. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. Other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. Figures are also merely representational and may not be drawn to scale. Certain proportions thereof may be exaggerated, while others may be minimized. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.

[00112] FIG. 12 and 13 is an illustration of a communication network 1300 for measurement and reporting in accordance with an exemplary embodiment. Briefly, the communication network 1300 expands broad data connectivity to other devices or services. As illustrated, the measurement and reporting system 1300 can be communicatively coupled to the communications network 1300 and any associated systems or services.

[00113] As one example, the measurement system 1355 can share its parameters of interest (e.g., angles, load, balance, distance, alignment, displacement, movement, rotation, and acceleration) with remote services or providers, for instance, to analyze or report on surgical status or outcome. This data can be shared for example with a service provider to monitor progress or with plan administrators for surgical monitoring purposes or efficacy studies. The communication network 1300 can further be tied to an Electronic Medical Records (EMR) system to implement health information technology practices. In other embodiments, the communication network 1300 can be communicatively coupled to HIS Hospital Information System, HIT Hospital Information Technology and HIM Hospital Information Management, EHR Electronic Health Record, CPOE Computerized Physician Order Entry, and CDSS Computerized Decision Support Systems. This provides the ability of different information technology systems and software applications to communicate, to exchange data accurately, effectively, and consistently, and to use the exchanged data.

[00114] The communications network 1300 can provide wired or wireless connectivity over a Local Area Network (LAN) 1301 , a Wireless Local Area Network (WLAN) 1305, a Cellular Network 1314, and/or other radio frequency (RF) system (see FIG. 4). The LAN 1301 and WLAN 1305 can be communicatively coupled to the Internet 1320, for example, through a central office. The central office can house common network switching equipment for distributing telecommunication services. Telecommunication services can include traditional POTS (Plain Old Telephone Service) and broadband services such as cable, HDTV, DSL, VoIP (Voice over Internet Protocol), IPTV (Internet Protocol Television), Internet services, and so on.

[00115] The communication network 1300 can utilize common computing and communications technologies to support circuit-switched and/or packet- switched communications. Each of the standards for Internet 1320 and other packet switched network transmission (e.g., TCP/IP, UDP/IP, HTML, HTTP, RTP, MMS, SMS) represent examples of the state of the art. Such standards are periodically superseded by faster or more efficient equivalents having essentially the same functions. Accordingly, replacement standards and protocols having the same functions are considered equivalent.

[00116] The cellular network 1314 can support voice and data services over a number of access technologies such as GSM-GPRS, EDGE, CDMA, UMTS, WiMAX, 2G, 3G, WAP, software defined radio (SDR), and other known technologies. The cellular network 1314 can be coupled to base receiver 1310 under a frequency-reuse plan for communicating with mobile devices 1302.

[00117] The base receiver 1310, in turn, can connect the mobile device 1302 to the Internet 1320 over a packet switched link. The internet 1320 can support application services and service layers for distributing data from the measurement system 1355 to the mobile device 1302. The mobile device 1302 can also connect to other communication devices through the Internet 1320 using a wireless communication channel.

[00118] The mobile device 1302 can also connect to the Internet 1320 over the WLAN 1305. Wireless Local Access Networks (WLANs) provide wireless access within a local geographical area. WLANs are typically composed of a cluster of Access Points (APs) 1304 also known as base stations. The measurement system 1355 can communicate with other WLAN stations such as laptop 1303 within the base station area. In typical WLAN implementations, the physical layer uses a variety of technologies such as 802.1 1 b or 802.1 1 g WLAN technologies. The physical layer may use infrared, frequency hopping spread spectrum in the 2.4 GHz Band, direct sequence spread spectrum in the 2.4 GHz Band, or other access technologies, for example, in the 5.8 GHz ISM band or higher ISM bands (e.g., 24 GHz, etc).

[00119] By way of the communication network 1300, the measurement system 1355 can establish connections with a remote server 1330 on the network and with other mobile devices for exchanging data. The remote server 1330 can have access to a database 1340 that is stored locally or remotely and which can contain application specific data. The remote server 1330 can also host application services directly, or over the internet 1320.

[00120] It should be noted that very little data exists on implanted orthopedic devices. Most of the data is empirically obtained by analyzing orthopedic devices that have been used in a human subject or simulated use. Wear patterns, material issues, and failure mechanisms are studied. Although, information can be garnered through this type of study it does yield substantive data about the initial installation, post-operative use, and long term use from a measurement perspective. Just as each person is different, each device installation is different having variations in initial loading, balance, and alignment. Having measured data and using the data to install an orthopedic device will greatly increase the consistency of the implant procedure thereby reducing rework and maximizing the life of the device. In at least one exemplary embodiment, the measured data can be collected to a database where it can be stored and analyzed. For example, once a relevant sample of the measured data is collected, it can be used to define optimal initial measured settings, geometries, and alignments for maximizing the life and usability of an implanted orthopedic device.

[00121] FIG. 14 is an exemplary method 1400 for distracting surfaces of the muscular-skeletal system in accordance with an exemplary embodiment. The method can be practiced with more or less than the number of steps shown and is not limited to the order shown. In a step 1402, sterilized sensors are removed from packaging. The sensors are powered up and enabled for sensing. One or more sensors are placed in a dynamic distractor. For example, the dynamic distractor used for a knee application will have two cavities for measuring each compartment of the knee. More specifically, a superior surface of the dynamic distractor has two cavities for receiving the sensors. The dynamic distractor is also in a sterilized condition.

[00122] In a step 1404, the dynamic distractor is inserted in the muscular- skeletal system. The superior and an inferior surface of the dynamic distractor is in contact with a first and second surface of the muscular-skeletal system. Continuing with the knee example, the inferior surface of the dynamic distractor is placed in the knee joint facing the proximal end of the tibia and the superior surface is placed in the knee joint facing the distal end of the femur. In one embodiment, the distal end of the tibia is prepared having a flat surface that is perpendicular to the mechanical axis of the leg.

[00123] In a step 1406, a handle of the dynamic distractor is rotated to increase a gap between the inferior and superior surfaces. As the gap increases the inferior surface is in contact with the distal end of the tibia. Similarly, the superior surface of the dynamic distractor contacts the distal end of the femur. In one embodiment, the condyles of the distal end of the femur contact the sensors of each compartment. In a non-limiting example, the dynamic distractor is placed in the knee joint such that the dynamic distractor is centrally located in the knee joint. The mechanical axis of the leg will align to the center of the dynamic distractor between the medial and lateral sides of the device. The handle of the dynamic distractor extends away from the knee joint on the mechanical axis of the leg.

[00124] In a step 1408, a parameter is measured by the sensors. In the example, the sensors measure load. More specifically the load in each compartment of the knee is measured at the height or gap created by the dynamic distractor. In one embodiment, the gap or height of distraction relates to the thickness of one or more components of an artificial joint such as the knee joint. The gap can correspond to the thickness of a final insert of the artificial joint. In general, final inserts typically comprise a polymer that provide a low-friction low-wear bearing surface. The final inserts are typically provided in a number of predetermined thicknesses of which one is selected for permanent insertion.

[00125] In a step 1410, the one or more sensors are removed from dynamic distractor. In general, the sensor is removed after the dynamic distractor is no longer needed in the surgery. In a step 1412, the sensor is disposed of after the surgery is completed. For example, the sensors can be disposed of as biological waste. The sensors as a disposable item alleviate substantial problems facing the health care industry. The high capital cost of traditional of surgical equipment often prevent purchase thereby preventing potentially beneficial equipment from being used. Disposables also eliminate the costly and time-consuming process of sterilization. The low cost of the sensors eliminates the capital cost issue thereby opening quantitative measurement of joint implants to a much larger audience. The result will be more consistent surgeries, ability to fine tune the surgery, longer implant life, and reduced post surgical complications to name but a few.

[00126] Steps 1414, 1416, and 1418 relate to optimal loading on the final insert for maximum joint life. In general, it is not desirable for the implanted joint to be too tight or loose. In a step 1414, the gap is increased until the loading is within a predetermined loading range and the gap corresponds to an available final insert thickness. In one embodiment, the gap is selected for a final insert thickness that measures a loading above the median of the predetermined range to allow for soft tissue release back within the predetermined range. In a step 1416, the gap is measured when the sensors measure loading within the predetermined range. Alternatively, the dynamic distractor can increase or decrease gaps incrementally that correspond to available inserts. In a step 1418, the insert is selected. As mentioned previously, the measured gap when the loading is within the predetermined range may not correspond to a final insert thickness. The surgeon can increase or decrease the gap to an available insert thickness (and measure load in each compartment) then select an insert based on subsequent steps of the procedure to be implemented by the surgeon.

[00127] Steps 1420 and 1422 relate to adjustments made while the dynamic distractor is inserted. In a step 1420, data from the sensors is transmitted to a processing unit. In a non-limiting example, the processing unit is external to the dynamic distractor and sensors. As disclosed herein, the processing unit can be part of a notebook computer. The data from the sensors in the dynamic distractor can be displayed for viewing by the surgeon and medical team. In a step 1422, the surgeon can adjust the loading using soft tissue release techniques with the dynamic distractor in place. In one embodiment, the dynamic distractor can have a bellows or removable skirt around the periphery of the device that prevents debris from collecting within the interior. The bellows or removable skirt is removed to allow access along the medial and lateral periphery of the dynamic distractor and between the upper and lower support structures of the dynamic distractor. Further access for soft tissue release is provided by removing the handle of the dynamic distractor or positioning the handle away from the surgical area.

[00128] Steps 1424 and 1426 relate to adjustments made when parameters are measured in more than one region. In the knee example, measurements are made in the two knee compartments corresponding to the medial and lateral condyles in contact with the sensors. In a step 1424, the loading is measured in each compartment. In one embodiment, the measured loading in the two regions should be approximately equal. The differential loading can be measured and then adjusted if outside a predetermined differential load range. In general, the side measuring the higher loading is adjusted. In a step 1426, soft tissue release is performed to adjust the difference between the loadings measured in each compartment. As disclosed herein, the loading can be measured in real time as the release occurs. The loading is then adjusted until the difference between the compartments is within the predetermined differential load range thereby adjusting the joint towards the optimum based on measurement.

[00129] Steps 1428, 1430, 1432, 1434, 1436, and 1438 relate to positioning and aligning the leg using the dynamic distractor. In step 1428, the leg is positioned using position information provided by the dynamic distractor. In one embodiment, accelerometers in the sensors provide information on the angle of the tibia in relation to the femur. Thus, the leg can be put precisely in extension (e.g. a 180-degree angle between the femur and tibia) and in flexion (less than 180-degree angle, for example a 90 degree angle between the femur and tibia). In a step 430, the positional information can be sent to an external processing unit and the information displayed on a display for viewing by the surgeon. The surgeon can place the leg in extension or flexion to prepare or shape the proximal end of the tibia or the distal end of the femur. In steps 1432 and 1434, the surgeon identifies the mechanical axis of the leg. In one embodiment, one or more lasers are coupled to the handle of the dynamic distractor in the knee joint. As mentioned previously, the handle of the dynamic distractor is located overlying the center of the knee. In the step 1432, a first laser emits a signal to a first target that is positioned proximally to the center of the ankle. The line from center of the ankle to the center of knee aligns with the mechanical axis of the leg. The first target is positioned where it overlies the mechanical axis on a plane corresponding to the beam from the first laser. Similarly, in a step 1434, a second laser emits a signal to a second target that is positioned proximally to the center of the femoral head. A straight line from the center of the femoral head through the center of the knee to the center of the ankle comprises the mechanical axis of the leg. The second target overlies the mechanical axis and is positioned on a plane corresponding to the beam from the second laser. The surgeon can then measure the misalignment of the leg to the mechanical axis and make corrections appropriately.

[00130] FIG. 15 is an exemplary method 1500 for distracting surfaces of the muscular-skeletal system in extension and in flexion in accordance with an exemplary embodiment. The method can be practiced with more or less than the number of steps shown and is not limited to the order shown. In a step 1502, a distractor is placed between surfaces of a muscular-skeletal system. As mentioned previously, the distractor can be broadly used on the muscular- skeletal system including but not limited to the spinal column, knee, hip, ankle, shoulder, wrist, articulating, and non-articulating structures. As disclosed above, the distractor comprises a lift mechanism between a first support structure and a second support structure. In one embodiment, a handle couples to the lift mechanism to rotatably raise and lower the lift mechanism thereby changing a gap between the surfaces of the support structures. In general, the first and second supports structures are placed between two surfaces of the muscular-skeletal system. In a non-limiting example, to illustrate the principal, the distractor can be used in joint repair or replacement surgery to separate bones comprising the joint as they are prepared for an implant. Examples are vertebrae of the spinal column, the distal end of the femur and the proximal end of the tibia of a knee joint, or the pelvis and the proximal end of the femur of the hip.

[00131] In a step 1504, the gap provided by the distractor is changed and the muscular-skeletal system is placed in a first relational position. The gap of the distractor can be changed under the control of the surgeon thereby changing the spacing between the two surfaces of the muscular-skeletal system being distracted. In one embodiment, the gap corresponds to a thickness of one or more components to be implanted in the muscular-skeletal system. The distractor is likely to be initially placed between the two surfaces having a minimum gap and then expanded to a predetermined height or thickness. The muscular-skeletal system is placed in a first relational position with the distractor inserted between the two surfaces. The first relation position corresponds to the positions of the surfaces and portions of the muscular-skeletal system attached thereto.

[00132] In a step 1506, at least one parameter is measured with a sensor. The muscular-skeletal system is in the first relational position when parameter is measured by the sensor. In one embodiment, the distractor includes a sensor for measuring a parameter. For example, the sensor can provide accurate measurements of parameters such as distance, weight, strain, pressure, wear, vibration, viscosity, and density that relate to the procedure being performed. The distractor further provides two or more surfaces in contact with the muscular-skeletal system for close proximity measurement by the sensor. As disclosed hereinabove, the sensor can be self contained in a housing, can be placed in a cavity on one or more of the distracting surfaces and includes an exposed surface that can couple to the muscular-skeletal system for sensing.

[00133] In a step 1508, the muscular-skeletal system is repositioned to a second relational position. In a non-limiting example, the second relational position corresponds to movement of the distracted surfaces and portions of the muscular-skeletal system attached thereto in relation to one another. The position of the distracted surfaces in the second position is different from the position of the distracted surfaces in the first position. The distractor remains in place during positioning to the second relational position. This provides the benefit of reducing surgical time and stress on the patient. In general, the support structures of the distractor and more specifically the surfaces of the support structure allow natural movement of the muscular-skeletal in a normal range of motion.

[00134] In a step 1510, at least one parameter is measured by the sensor while in the second relational position. In one embodiment, the distractor remains in place while the measurement is taken. The surgeon or medical staff can compare measurement data with the muscular-skeletal system in two different positions. Often the measurement data will be similar throughout the range of motion or differ by a known amount due to geometrical differences of the position. Referring to a step 1518, the sensor can include a transmitter for transmitting measurement data from the sensor to a processing unit. The processing unit can be a logic circuit, digital signal processor, microcontroller, microprocessor, or analog circuitry. The processing unit can be part of a larger system such as a multi-component custom system or a commercially available notebook computer or personal computer. In a step 1520, the measurement is displayed on a display. The data can be processed by the processing unit and a GUI (graphical user interface) integrated with the display to present the data, enhance use of the data, interpret the data, and contemplate or detail corrections that may be needed to be made based on the data. The transmission of the data can occur as measurements over a range of motion and at least in the first relational position and the second relational position. In one embodiment, the distractor provides measurement data on the amount of distraction or gap produced by the device. This measurement data can also be transmitted along with the relational position data of the muscular-skeletal system. Thus, the distractor provides the benefit of measurement data being taken with the sensor at different points of the range of motion and at different gap heights without being removed.

[00135] In a step 1512, the sensor is placed on a surface of the distractor. In one embodiment, the sensor is a disposable device. The support structures of the distractor can have one or more recesses or cavities for receiving a sensor on a surface of the device. In particular, a cavity can be formed on a major surface of a support structure that comes in contact with a surface of the muscular-skeletal system during distraction. In a non-limiting example, one or more sensors are placed in one more cavities prior to insertion between the two surfaces of the muscular-skeletal system. The sensors are activated and in communication with the processing unit for taking measurements on the muscular-skeletal system. In a step 1514, the sensor is coupled to a surface of the muscular-skeletal system. As disclosed herein, the sensor can include a major surface that is exposed and substantially parallel to the major surface of a support structure. The sensor comes in contact with the muscular-skeletal system as the two surface of the muscular-skeletal system are distracted. Typically, as distraction increases a compressive force by the two surfaces of the muscular-skeletal system is applied to the two support structures placing the sensor in intimate contact with the surface. Alternatively, the sensor can be located on or in proximity to the distractor if direct contact is not required for the measurement.

[00136] In a step 1522, the alignment of at least one of the first or second relational position is compared to a mechanical axis of the muscular-skeletal system. Typically, the muscular-skeletal system has optimal alignments that maximize performance of the structure. The distractor can be used to measure misalignment to the mechanical axis. The distractor utilizes at least one of the surface being distracted to measure the misalignment. The distracted surface of the muscular-skeletal system has a geometric relationship with the mechanical axis. For example, the plane of the distracted surface can be a specific angle from the mechanical axis. Moreover, there can be specific landmarks of the surface that such as a center point that further identify the relationship with the mechanical axis.

[00137] In one embodiment, a plane of a portion of the surface of the distractor is co-planar with the muscular-skeletal surface it is contacting. This relationship is extended to a handle of the distractor where a surface of the handle is co-planar to the distracted surface of the muscular-skeletal system. The handle can also extend from muscular-skeletal system at a location corresponding to a landmark that corresponds to the mechanical axis. For example, it can extend centrally or at a specific position from the distracted surface. As disclosed hereinabove, a drop rod can be attached to an opening in the handle to visually and subjectively determine if alignment is within a predetermined range. The drop rod can also be coupled to other fixtures coupled to different areas of the muscular-skeletal system to measure alignment. Alternatively, one or more lasers can be attached to the handle of the distractor. The lasers are directed to one or more targets that are located along the mechanical axis. The amount of misalignment can be measured by the location where the beam hits a scale on each of the target. [00138] In a step 1524, the muscular-skeletal system is modified to reduce the measured misalignment. In general, there will be an acceptable range for misalignment to the mechanical axis. Adjustments are made to reduce the error if the measurement is outside the acceptable range. Modifications to the muscular-skeletal system can take many forms. Material can be added or removed from the bone structure. Soft tissue release of the muscles, tendons, and ligaments can also be used to modify alignment. Additionally, other structures and materials that are both biological and artificial can be used to change or be added to the muscular-skeletal system to bring the two surfaces into alignment. After the modifications are performed, the alignment can be rechecked to verify that the misalignment error is with an acceptable range.

[00139] In a step 1526, the handle is used to direct the placement of the distractor between the two surfaces of the muscular-skeletal system. The handle of the distractor provides an external means for the surgeon to locate and position the first and second support structures of the distractor accurately in the muscular-skeletal system. In one embodiment, the handle is coupled to a lift mechanism that generates the gap between the first and second support structures. In a step 1528, the gap height can be varied using the handle. The handle is coupled to a shaft of the lift mechanism. In a non-limiting example, the handle is rotated to increase or decrease the gap of the distractor.

[00140] In a step 1530, the handle is moved away from the surgical area. The distractor is designed to provide access to areas in proximity to the two surfaces being distracted by the device. One access area is anterior to the two surfaces of the distracted muscular-skeletal system. Access is desirable to perform a surgical procedure or other step with the distractor in place. A benefit of the distractor is that the handle is hinged allowing it to be moved away from the area where the surgical procedure is being performed. Alternatively, in a step 1536, the handle is removed from the distractor also giving unobstructed anterior access. The distractor also has peripheral access and access between the first and second support structures when a gap is created. In one embodiment, the distractor has a bellows like skirt around the periphery of the device that is inserted between the two surfaces of the muscular-skeletal system. The skirt prevents materials or debris from the procedure from getting between the first and second support structures of the distractor. The skirt can be removed when a procedure is performed requiring anterior, posterior, medial, or lateral access. Alternatively, the periphery can be open and the interior space between the first and second support structures can be cleaned periodically to prevent build up of debris. The distractor provides open space anterior, posterior, medially, laterally, and between the first and second support structures allowing the surgeon great latitude in performing surgical procedures in proximity to the distracted area.

[00141] In a step 1532, the muscular-skeletal system is modified in the first relational position. As disclosed above, modifications to the muscular-skeletal system can take many forms. Bone modification, soft tissue release, implants, adding artificial or biological materials are but a few of the modifications that can be made using the access provided by the distractor. Similarly, in a step 1534, the muscular-skeletal system is modified in the second relational position. In one embodiment, the distractor is not removed during sensor measurement, movement through a range of motion, and during the modification process thereby greatly reducing the surgical time. Moreover, sensors in the distractor can provide real time measurement of how the modifications are affecting the distracted region. This instant feedback and quantitative measurement allow fine adjustments to be made that will greatly increase the consistency of orthopedic surgical procedures.

[00142] FIG. 16 is an exemplary method 1600 for distracting surfaces of the muscular-skeletal system in extension and in flexion in accordance with an exemplary embodiment. The method can be practiced with more or less than the number of steps shown and is not limited to the order shown. Steps 1602, 1604, and 1606 are respectively similar to steps 1502, 1504, and 1506 of FIG. 15 and are not described here for brevity. In a step 1608, the measured parameter is changed through modification of the muscular-skeletal system. As mentioned previously, the distractor can be broadly used on the muscular- skeletal system including but not limited to the spinal column, knee, hip, ankle, shoulder, wrist, articulating, and non-articulating structures. In one embodiment, the measurement and the modification of the muscular-skeletal system occurs with the distractor in place and the leg in extension.

[00143] In a step 1610, the muscular-skeletal system is repositioned to a second relational position. As mentioned previously, the position of the distracted surfaces in the second position is different from the position of the distracted surfaces in the first position. The distractor remains in place during positioning to the second relational position. This provides the benefit of reducing surgical time and stress on the patient. In general, the support structures of the distractor and more specifically the surfaces of the support structure allow natural movement of the muscular-skeletal in a normal range of motion.

[00144] In a step 1612, at least one parameter is measured by the sensor while in the second relational position. In a step 1614, the measured parameter is changed through modification of the muscular-skeletal system. The modification occurs with the muscular-skeletal system in the second relational position. In one embodiment, the distractor remains in place while moving the muscular-skeletal system to the second relational position, during sensor measurement, and modification of the muscular-skeletal system. The surgeon or medical staff can compare measurement data with the muscular- skeletal system in at least two different positions. Referring to a step 1628, the sensor can include a transmitter for transmitting measurement data from the sensor to a processing unit. In a step 1630, the measurement is displayed on a display. For example, the processing unit can be the microprocessor of a notebook while the display is the screen of the notebook. The data is transmitted in real time when a measurement is taken. In other words, the data is transmitted, processed, and displayed during the measurement and subsequent modification of the muscular-skeletal system in the first relational position. Similarly, the data is transmitted, processed, and displayed during the measurement and subsequent modification in the second relational position. The transmission of measured data can sent wirelessly using a radio frequency signal. [00145] In a step 1522, the alignment of at least one of the first or second relational position is compared to a mechanical axis of the muscular-skeletal system. Typically, the muscular-skeletal system has optimal alignments that maximize performance of the structure. The distractor can be used to measure misalignment to the mechanical axis. The distractor utilizes at least one of the surface being distracted to measure the misalignment. The distracted surface of the muscular-skeletal system has a geometric relationship with the mechanical axis. For example, the plane of the distracted surface can be a specific angle from the mechanical axis. Moreover, there can be specific landmarks of the surface that such as a center point that further identify the relationship with the mechanical axis.

[00146] In one embodiment, a plane of a portion of the surface of the distractor is co-planar with the muscular-skeletal surface it is contacting. This relationship is extended to a handle of the distractor where a surface of the handle is co-planar to the distracted surface of the muscular-skeletal system. The handle can also extend from muscular-skeletal system at a location corresponding to a landmark that corresponds to the mechanical axis. For example, it can extend centrally or at a specific position from the distracted surface. As disclosed hereinabove, a drop rod can be attached to an opening in the handle to visually and subjectively determine if alignment is within a predetermined range. The drop rod can also be coupled to other fixtures coupled to different areas of the muscular-skeletal system to measure alignment. Alternatively, one or more lasers can be attached to the handle of the distractor. The lasers are directed to one or more targets that are located along the mechanical axis. The amount of misalignment can be measured by the location where the beam hits a scale on each of the target.

[00147] In a step 1616, the misalignment of the muscular-skeletal system is measured. As disclosed above, the measurement can be made using lasers and targets respectively coupled to the handle of the distractor and located along the mechanical axis of the muscular-skeletal system. In one embodiment, the misalignment is referenced to at least one of the two surfaces being distracted by the distractor. The alignment of the surface of the muscular-skeletal system is compared to the mechanical axis. In a step 1618, the muscular-skeletal system is modified to reduce the measured misalignment. As mentioned previously, there is an acceptable range for misalignment to the mechanical axis. Adjustments are made to reduce the error if the measurement are outside the acceptable range. In one embodiment, the corrections can be checked in real time as the modifications are made to see that the changes to the muscular-skeletal system are moving the misalignment error to the acceptable range.

[00148] In a step 1620, the sensor measures load. In one embodiment, the two surfaces of the muscular-skeletal system place a compressive force across the first and second support structures of the distractor. One or more sensors on the first and second support structures of the distractor can be used to measure loading and the distribution of loading. In a step 1622, the handle of the distractor is moved away from a surgical area. In non-limiting example, the surgical area corresponds to a region where muscles, tendons, and ligaments couple the at least two surfaces of the muscular-skeletal system together. The handle is moved to a position such that modification to the soft tissue can take place. In a step 1624, soft tissue is cut in the surgical area to reduce loading applied by the two surfaces of the muscular-skeletal system on the distractor. In general, the sensor can measure load, pressure, or force. The distractor provides access for the surgeon to make cuts to the soft tissue with the area distracted. The sensor measures in real time allowing the surgeon to adjust the load to an optimal value. In a step 1626, the handle can be removed to further improve the anterior access.

[00149] FIG. 17 is an exemplary method 1700 for distracting surfaces of a knee joint in extension and in flexion in accordance with an exemplary embodiment. The method can be practiced with more or less than the number of steps shown and is not limited to the order shown. A knee joint implant procedure of the muscular-skeletal system is used to illustrate the process of distraction. The knee joint comprises the distal end of the femur and the proximal end of the tibia. An artificial knee joint comprises a femoral implant, an insert, and a tibal implant. The femoral implant is shaped similar to and replaces the natural condyles at the distal end of the femur. The insert has a bearing surface for receiving the condyles and an inferior surface that mates and is retained by the tibial implant. In general, the artificial knee joint mimics the natural knee joint in operation once implanted.

[00150] All the steps for preparing a knee will not be disclosed for brevity but are well known by one skilled in the art. The knee is opened by incision to expose the distal end of the femur and the proximal end of the femur. The patella is removed or moved away from the knee joint region. The proximal end of the tibia is prepared by cutting the bone. In one embodiment, the proximal end of the tibia is prepared having a planar surface. In one embodiment, the planar surface is cut perpendicular to the mechanical axis of the leg. The distractor is then inserted into the knee joint.

[00151] The distractor has a first support structure having a superior surface for receiving the condyles of the femur and a second support structure having an inferior surface for mating to the prepared tibial surface. The shape of the support structures as disclosed herein allows natural movement of the leg through the range of motion with the distractor in place. In one embodiment, two sensors are placed in the superior surface of the distractor for measuring load in each compartment of the knee. A handle is used to direct the first and second support structures into the knee. The handle can be rotated to increase the gap of the distractor to place the superior surface of the first support structure in contact with the condyles of the femur and the inferior surface of the second support structure in contact to the tibial surface. More specifically, each condyle will contact a surface of a corresponding sensor.

[00152] In a step 1720, the alignment of a surface of the distractor is compared to the mechanical axis of the leg. The surface of the distractor corresponds to a surface of the knee. In one embodiment, the surface is the prepared surface of the tibia. Targets for leg alignment can be placed overlying the mechanical axis of the leg. Typically one target is placed in the ankle or foot region and a second target is placed in the hip joint region near the femoral head. The mechanical axis is a straight line from the center of the femoral head through the center of the knee joint to the center of the ankle. In one embodiment, handle extends from the knee joint at a point that corresponds to the center of the knee joint. The inferior surface of the second support structure is planar to the tibial surface. Similarly, one or more surfaces of the handle of the distractor is aligned to the inferior surface of the second support structure thereby being co-planar to the tibial surface. As disclosed hereinabove, lasers can be attached to the handle pointing towards the ankle target and the hip target. As mentioned previously, the tibial surface is prepared to be 90 degrees from the mechanical axis of the leg. Misalignment from the mechanical axis can be measured from where the beam of the laser hits the target. A correctly aligned leg will hit each target at a point representing the location of the mechanical axis. In a step 1722, the measured misalignment can be reduced through modification of the muscular- skeletal system. The modification can be to the bone, soft tissue, additional implants or materials (artificial and biological) that bring the femur and tibia into alignment with the mechanical axis.

[00153] In a step 1702, the knee joint is distracted with the leg in extension. The leg is in extension when the femur and tibia are positioned having a 180- degree angle between them. A handle of the distractor directs the support structures into the knee joint area. The handle is rotated to increase a gap between the superior and inferior surfaces until contact is respectively made to the condyles of the femur and the surface of the tibia. The sensors in each compartment of the first support structure are in communication with an external processing unit. In one embodiment, each condyle of the femur is in contact with a corresponding sensor surface throughout the range of motion of the leg. The surgeon positions the distractor such that the handle corresponds to the center of the knee joint, which aligns with the mechanical axis of the leg. In a non-limiting example, the leg alignment to the mechanical axis can be measured and corrections made to reduce misalignment if outside an acceptable range.

[00154] In a step 1704, a load is measured with the leg in extension for at least one compartment of the knee. The data is received by the processing unit and displayed on a display. For example, accelerometers in the sensors can show relative position of the femur to the tibia. In one embodiment, the femur and tibia are shown on the display to provide visual information to the surgeon on positioning. The angle between the femur and tibia can be displayed as well as alignment of the leg to the mechanical axis. The sensors include a measurement device such as a strain gauge to measure load. A complete knee replacement will measure loading on both compartments of the knee.

[00155] The distractor provides quantitative data that is used by the surgeon to prepare the knee. In a non-limiting example, the knee is distracted to a gap that corresponds to a combined insert and tibial implant thickness (the distal end of the femur is unprepared in the example). As is known by one skilled in the art, inserts are available in different sizes and thicknesses. The surgeon picks a size that is best adapted for the patient bone dimensions. The surgeon prepares the bone surfaces for an approximate combined thickness of the implants. For illustration purposes a combined implant thickness of 20 millimeters could be used. Typically, several insert thicknesses are suitable based on the tibial cut and the resulting gap between the tibial surface and the condyles of the femur. The sensor measurements are used to select an appropriate range and allows fine-tuning of the loading to within a very accurate range. For the full joint replacement, the gap height of the distractor, angle between tibia/femur (180 degrees, leg in extension), the loading on each compartment at the gap height, and the differential loading between the compartments is transmitted and displayed for viewing by the surgeon.

[00156] In a non-limiting example, the surgeon may have to increase or decrease the gap height of the distractor depending on the sensor readings. The increase or decrease in gap height will correspond to an available insert thickness. In one embodiment, the surgeon adjusts the gap height to measure load on the high side of a predetermined load range for each compartment. Selecting on a high side reading allows for fine adjustments to the final load value in a subsequent step. In general, the surgeon selects the appropriate insert size for the knee implant. [00157] In a step 1706, the leg is moved into flexion while the distractor remains in the knee joint. As mentioned previously, the distractor provides surfaces that allows movement of the joint through the natural range of motion. This provides the benefit of being able to prepare the leg for load, balance, and alignment in more than one position using a single device. In one embodiment, the gap height of the distractor remains in the selected height for the leg in extension. Alternatively, the gap height of the distractor can be reduced while moving the leg in flexion to a final position and then readjusting the gap. In a non-limiting example, the leg is moved in flexion to a position where the femur and tibia form a 90-degree angle. In one embodiment, the surgeon can move the leg while viewing femur/tibia angle on the screen to get it precisely positioned.

[00158] In a step 1708, the load in at least one knee compartment is measured with the leg in flexion. In a non-limiting example, the gap height of the distractor in flexion is equal to the gap height selected by the surgeon when the leg was in extension. The sensors communicate with the processing unit providing the measured load in each compartment, differential loading between compartments, and the gap height to the surgeon with the leg in flexion. Thus, the leg can be moved from extension to flexion with the distractor in place. The sensors can measure load and differential loading in different positions and gap heights that can be displayed on a screen for the surgeon to view. The data is also stored in memory for use.

[00159] In a step 1710, the handle of the distractor is moved from a surgical area with the leg in extension. As mentioned previously, the handle of the distractor includes a hinge to position the handle away from a surgical area or can be removed to have anterior access to the distracted area. The surgical area corresponds to the muscle and ligaments coupling the femur to the tibia. The muscle and ligaments in the surgical area are located laterally and medially around the knee joint. A space is typically opened between the first and second support structures when the knee joint is distracted. Thus, the distractor enables soft tissue release by providing access from multiple vantage points to the muscle and ligaments with the device in place. [00160] In a step 1712, the load in at least one compartment of the knee is reduced with the leg in extension. The handle is positioned to allow anterior and peripheral access to the soft tissue for incision. The surgeon can also place a scalpel between the first and second support structures for an interior or peripheral cut to the soft tissue if needed. In a non-limiting example, the soft tissue release can be performed when the leg is in extension after the loading is measured and the gap adjusted to a height selected by the surgeon. The soft tissue release can be performed on either the lateral or the medial sides of the knee or on both sides. In one embodiment, the soft tissue release is performed to bring each compartment loading within a predetermine loading range. The sensor data is transmitted, processed, and displayed in real time allowing the surgeon to view the actual measured effect of each cut on the loading in both compartments.

[00161] Referring to a step 1714, the load, force, or pressure in both knee compartments are measured with the leg in extension. In a step 1716, the measured load in each compartment is compared and a differential loading is calculated. In a step 1718, the differential loading between the two knee compartments is reduced using soft tissue release with the distractor in the knee joint. The surgeon can fine-tune the leg in extension to balance the loading between compartments with the distractor in place. In one embodiment, the surgeon can reduce the measured load on the side reading the highest value and bring the differential loading down within a predetermined differential loading range. In the example, the absolute loading measured in each compartment has also been reduced within a predetermined acceptable load range. As previously disclosed, the gap generated by the distractor corresponds to an available thickness insert of the artificial knee joint. The display can provide indicators to the surgeon when the measured load or the differential load is within their respective appropriate ranges.

[00162] In a step 1722, the handle of the distractor is moved from a surgical area with the leg in flexion. As mentioned previously, the leg is positioned with the femur and tibia at a right angle. In a step 1724, the load in at least one compartment of the knee is reduced with the leg in flexion. The handle is positioned to allow anterior and peripheral access to the soft tissue for incision. The surgeon can also place a scalpel between the first and second support structures for an interior or peripheral cut to the soft tissue if needed. In a non- limiting example, the soft tissue release can be performed when the leg is in extension after the loading is measured and the gap adjusted to a height selected by the surgeon. The soft tissue release can be performed on either the lateral or the medial sides of the knee or on both sides. In one embodiment, the soft tissue release is performed to bring each compartment loading within a predetermine loading range. The sensor data is transmitted, processed, and displayed in real time allowing the surgeon to view the actual measured effect of each cut on the loading in both compartments with the leg in flexion.

[00163] In a step 1726, the load, force, or pressure in both knee compartments are measured with the leg in flexion. In a step 1728, the measured load in each compartment is compared and a differential loading is calculated. In a step 1730, the differential loading between the two knee compartments with the leg in flexion is reduced using soft tissue release with the distractor in the knee joint. The surgeon can fine-tune the leg in extension to balance the loading between compartments with the distractor in place. In one embodiment, the surgeon can reduce the measured load on the side reading the highest value and bring the differential loading down within a predetermined differential loading range. In the example, the absolute loading measured in each compartment has also been reduced within a predetermined acceptable load range. As previously disclosed, the gap generated by the distractor corresponds to an available thickness insert of the artificial knee joint. In the non-limiting example, the gap created by the distractor in extension and flexion is the same. The display can provide indicators to the surgeon when the measured load or the differential load is within their respective appropriate ranges when the leg is in flexion. The surgeon can take further measurements on load and balance by moving the leg in different positions of flexion and recording the values. Further adjustments could be made to refine load and balance in these other flexion positions with the distractor in place. [00164] FIG. 18 is an exemplary method 1800 to place the muscular-skeletal system in a fixed position for bone shaping in accordance with an exemplary embodiment. The method can be practiced with more or less than the number of steps shown and is not limited to the order shown. A spacer is a device that as it names implies spaces two surfaces apart from each other. A spacer can have a fixed height or can be variable. In one embodiment, a spacer has an inferior surface and a superior surface for coupling to surfaces of the muscular-skeletal system. A spacer with a fixed height is also known as a spacer block in the orthopedic field. A spacer having variable height is known as a distractor.

[00165] In a step 1802, a spacer is placed between two surfaces of the muscular-skeletal system. The spacer separates the two surfaces of the muscular-skeletal system. In one embodiment, the spacer is placed between two bones. The superior surface of the spacer couples to a surface of a first bone and the inferior surface couples to a surface of a second bone. There can be other material or components between the superior and inferior surface of spacer and the bone surfaces. Thus, the spacer separates the first and second bone surfaces by at least the height of the spacer.

[00166] In a step 1804, a cutting block is coupled to an exposed portion of one of the two bone surfaces. A cutting block is a template for shaping a bone surface. It is typically fastened to a bone surface and can have slots and openings for guiding surgical tools such as a bone saw. In one embodiment, a cutting block is used to shape a bone end for receiving one or more artificial implant components or material. In many cases, the position of the cutting block is not arbitrary but has to have precision alignment. For example, when performing a joint replacement, the cutting block has to be positioned having one or more alignments to the muscular-skeletal system. Misalignment can cause joint failure and premature wear. An illustration of alignment will be disclosed in more detail by example hereinbelow.

[00167] In a step 1806, the spacer is coupled to the cutting block to rigidly position the two surfaces in a predetermined position. Cutting blocks are typically designed to be used to shape the bones with the two surfaces and more specifically the bones having the surfaces in a specific position and alignment. In one embodiment, the spacer is fixed in position to at least one of the bone surfaces. The spacer can be under compressive force due to muscle, ligaments and tendons coupling the first and second bones together. Alternatively, the spacer can be temporarily attached to one of the surfaces. For example, a surgical screw or pin can be used to fix the spacer position. If the spacer is a distractor, the compressive force can be adjusted by increasing or decreasing the height between the superior and inferior surfaces. The spacer can allow the two bones to move in relation to one another in a natural range of motion without movement of the device to the bone surface. The spacer and the cutting block are couple together to prevent movement of the first bone, second bone, bone surfaces, and cutting block. Coupling the spacer to the cutting block stabilizes the cutting block and keeps the first and second bones in a fixed relation to one another while the bone surface is shaped.

[00168] In a step 1810, the misalignment of at least one of the surfaces is measured in relation to a mechanical axis of the muscular-skeletal system. In general, alignment of the muscular-skeletal system is critical to obtain optimal performance and longevity. In fact, many problems that end up requiring surgery are due to misalignment or deformity that causes premature wear or damage to the muscular-skeletal system that can directly or indirectly result in a disability or health problem. Implanted devices and artificial joints follow similar constraints from a geometric standpoint since many mimic the natural device. Thus, the surgeon needs affirmation that the alignment of the muscular-skeletal system while modifying bone and soft tissue to receive implanted components. Typically, at least one of the bone surfaces has a relationship with a mechanical axis of the muscular-skeletal system. The mechanical axis is an optimal alignment of the bone or bone surface to another portion of muscular-skeletal system. In a non-limiting example, the bone surfaces and the thus the bones having the bone surfaces have an optimal alignment. This optimal alignment is known as the mechanical axis. [00169] In one embodiment, a surface or feature of the handle corresponds to a surface of the muscular-skeletal system. This relationship can be used to compare the orientation of the surface or feature to a mechanical axis. The superior or inferior surface of the spacer couples to the surface (or reference surface). The surface of the spacer is shaped similarly to the reference surface. For example, if the reference surface of the muscular-skeletal system is planar, the spacer surface is also made planar and has a relational position of being co-planar or parallel to the reference surface. A feature or the surface of a feature such as an opening, recess, mounting structure can have a specific orientation to the reference surface. For example, an opening can have an orientation that is perpendicular to the reference surface. Thus, the opening will extend in a direction approximately perpendicular to the muscular- skeletal reference surface on which the spacer is coupled. The handle can have one or more surfaces or features made to have specific relational positions to one or both of the spacer surfaces. For example, at least one surface of the handle can be made co-planar to the spacer surface corresponding to the muscular-skeletal reference surface. The surface on the handle can be used to create features that have specific positional relationships to the plane of the muscular-skeletal reference surface to aid in determining misalignment. Measurement of misalignment will be discussed in more detail hereinbelow.

[00170] As disclosed hereinabove, the mechanical axis can be defined by placing targets overlying the patient that align to the axis or to reference points of the body. For illustrative purposes, the leg in extension will be used to describe a mechanical axis of the muscular-skeletal system for a knee joint replacement. The mechanical axis of the leg in extension is a straight line from the center of the femoral head, to the center of the knee joint, and continuing to the center of the ankle. The targets are placed above the mechanical axis and typically near the ankle region and the center of the femoral head. In one embodiment, the handle is aligned with the center of the knee joint and extends vertically from the knee. In a non-limiting example, a feature such as a center of at least one opening or a recess in the handle is geometrically aligned to the knee center and corresponds to a point on the mechanical axis. The mechanical axis corresponds to a straight line from a point on the ankle target (e.g. ankle center), to a point on the handle, and extending to a point on hip target (e.g. center of femoral head). Extending a plane of the mechanical axis vertically (e.g. 90 degrees to the horizontal plane) with the leg in extension would intersect the center of the feature on the handle. In the example, the proximal end of the tibia is prepared by the surgeon as a flat surface. Ideally, the mechanical axis of the intersects the plane of the prepared tibial surface at a right angle. In a non-limiting example, lasers are coupled openings or recesses in the handle of the spacer. The lasers point towards the ankle target and the hip target. The lasers are pointed at a 90- degree angle from the plane of the prepared bone surface. Thus, misalignment can be measured from the targets as the difference angle between the point where beams hit the target and the identified point on each target corresponding to the mechanical axis.

[00171] In a step 1812 the muscular-skeletal system is modified to reduce the misalignment within a predetermined range. Once the misalignment is measured the surgeon can determine if modification to the muscular-skeletal system is required and what type of modification is suitable to reduce the error. In general, keeping the misalignment within a predetermined range will improve consistency of the surgery. Implant manufacturers can use the surgical data to determine the sensitivity of misalignment to rework, patient problems, and implant longevity.

[00172] In a step 1814 the spacer is aligned between the two surfaces where a handle of the spacer intersects the mechanical axis. Typically, the spacer alignment occurs before the misalignment to the mechanical axis is measured. As disclosed above, the spacer is part of an alignment system. The spacer has a predetermined position or alignment between the first and second bone surfaces and more specifically on the reference bone surface. In one embodiment, the handle extends from the spacer and intersects the mechanical axis. In the non-limiting example, the spacer is placed on the prepared tibial surface such that a superior surface of the spacer mates with the condyles of the femur. Moreover, the handle extends centrally from the spacer with the leg in extension corresponding to the center of the knee joint (e.g. a point on the mechanical axis).

[00173] In a step 1816, a rod is coupled to the handle. The handle has a known relational positioning to the mechanical axis within the predetermined range as described hereinabove. In one embodiment, the rod fits into an opening in the handle. The rod can be fastened to the handle. For example, portions of the rod and the opening in the rod can be threaded. Alternatively, the rod can be held in place by a powerful magnet, clamp, screw, or other means. In general, the rod is rigid and projects the positional relationship of the handle (e.g. the bone reference surface). In the knee example, the tibia and femur are placed in flexion. More specifically, the tibia and femur are positioned having a 90-degree angle between the bones. The cutting block is on the exposed portion of the distal end of the femur to be shaped. Thus, the entire distal end of the femur is not shaped in this position.

[00174] In a step 1818, the rod is coupled to the cutting block. The rod is then coupled to both the handle and the cutting block. In one embodiment, the cutting block has a channel approximately the same diameter as the rod. The rod is placed in the channel of the cutting block. The rod fixes the position of the spacer and the cutting block. As mentioned previously, the spacer and the handle is within a predetermine range of the mechanical axis. In a non-limiting example, the rod extends along the mechanical axis. Placing the rod into the channel aligns the cutting block to the mechanical axis. The rod fixes the relational position of the first bone surface to the second bone surface. In the embodiment, the femur and tibia are aligned to the mechanical axis and positioned perpendicular to each other.

[00175] In a step 1820, the gap of the spacer is changed. In one embodiment, the spacer is a dynamic distractor. The dynamic distractor includes sensors to measure loading. As the gap of the distractor is increased the first and second bone surfaces apply a compressive force on the spacer. The muscle, ligaments, and tendons couple the two bones holding them together under tension. The gap can be adjusted to be within a predetermined measured loading range (at the distracted gap height). [00176] In a step 1822, the bone surface is shaped. The cutting block is used as a template to direct a saw blade to shape the bone. With the rod rigidly holding the bone surfaces in place the cutting block is stabilized and in alignment with the mechanical axis. In the knee example, the exposed portion distal end of the femur can be shaped with the leg in flexion. The shaped surface can receive an implant that will be aligned correctly to the mechanical axis as well as the femur and tibia surfaces.

[00177] FIG. 19 is an exemplary method 1900 of measuring the muscular- skeletal system in accordance with an exemplary embodiment. The method can be practiced with more or less than the number of steps shown and is not limited to the order shown. In a non-limiting example a spacer separates two surfaces of the muscular-skeletal system. The spacer has an inferior surface and a superior surface that contact the two surfaces. The spacer can have a fixed height or can have a variable height. The variable height spacer is known as a distractor. A handle extends from the spacer and typically resides outside or beyond the two surface regions. The handle is used to direct the spacer between the two surfaces. In one embodiment, the handle operatively couples to a lift mechanism of the distractor to increase and decrease a gap between the superior and inferior surfaces of the spacer. The spacer and handle is part of a system to measure alignment of the muscular-skeletal system. In one embodiment, at least one of the surfaces of the muscular- skeletal system that contacts the spacer has an optimal alignment to a mechanical axis of the muscular-skeletal system. The system measures the surface to mechanical axis alignment. In a non-limiting example, the surface can be corrected by a surgeon when the surface is misaligned to the mechanical axis outside a predetermined range.

[00178] A surface or feature of the handle has a relational position to the (reference or alignment) surface of the two surfaces that the spacer contacts. In one embodiment, the reference surface of the muscular-skeletal system is a planar surface. The surface of the spacer contacting the reference surface of is also planar and thus has the relational position of being planar or co-planar when coupled thereto. Similarly, the handle is attached or coupled to the spacer block or distractor having a relational position to the surface of the spacer that contacts the reference surface. Typically, the relational position of the surface or feature on the handle is co-planar or perpendicular to the surface of the spacer.

[00179] The two surfaces of the muscular-skeletal system are typically positioned in predetermined relation before measuring misalignment to the mechanical axis. The predetermined relation typically corresponds to a natural position of the muscular-skeletal system. For example, a common position is the tibia positioned 180 degrees from the femur, which is commonly known as a leg in extension. In this example, the reference surface is a proximal tibial surface of the tibia. In one embodiment, the proximal tibial surface is a planar surface prepared by the surgeon. Ideally, the tibial surface is formed perpendicular to the mechanical axis with the leg in extension. A measurement of the tibial surface to the mechanical axis is performed to verify that it is within a predetermined range or specification. Similarly, a measurement is often taken with the muscular-skeletal system in a second predetermined relation. The second predetermined relation is typically at a different point in the range of natural motion. For example, the leg in extension with the tibia positioned 90 degrees from the femur. One or more sensors such as accelerometers can be use to measure the relational positioning of the two surfaces of the muscular-skeletal system.

[00180] In one embodiment, a feature such as an opening or cavity is formed in the handle. The opening or cavity has a relational positioning to the reference surface when the spacer block or distractor is placed between the two surfaces of the muscular-skeletal system. In a non-limiting example to illustrate the relational positioning, the opening or cavity is perpendicular to the plane of the reference surface. In the example where the mechanical axis is ideally perpendicular to the reference surface a rod is placed in the opening or cavity. The rod is directed perpendicular to the plane of the reference surface. A comparison of the direction of the rod to the mechanical axis yields misalignment of the reference surface to the ideal. The surgeon can use the rod with landmarks that identify the mechanical axis to make a visual determination of alignment. Alternatively, the rod can be used to measure an angle difference between the mechanical axis and the actual muscular-skeletal alignment. Furthermore, the rod can include one or more sensors for measuring a parameter of the muscular-skeletal system including alignment.

[00181] In another embodiment, targets are placed on the muscular-skeletal system aligned with the mechanical axis. An axis point or axis line on the target aligns with the mechanical axis. A laser is placed in the opening or cavity on the handle. In a non-limiting example, the center of the opening or cavity corresponds to an axis point on the mechanical axis. The mechanical axis is a straight line between the center of the opening and one or more targets. The beam of the laser is directed to the target. Using the example above, the beam is directed perpendicular to the plane of the reference surface to the target. The position where the beam hits the target corresponds to misalignment of the reference surface to the mechanical axis. The misalignment results in the beam hitting the target on either side of the axis point or line. In a similar fashion the location of the beam on the target could also be used to determine if the reference surface has a slope by viewing where the beam hits the target in an opposite plane. For example, if the misalignment measurement is on a horizontal plane relative to the axis point, a slope of the reference surface can correspond to the beam location on a vertical plane or above/below the axis point.

[00182] In a step 1902, two surfaces of the muscular-skeletal system are distracted with a distractor. The gap between the two surfaces can be varied with the distractor. In a step 1904, an alignment aid is coupled to a handle of the distractor. The misalignment of a surface of the two surfaces to a mechanical axis is measured with an alignment aid that is coupled to a handle of the distractor. The alignment aid is coupled to a surface or feature of the handle of the distractor that has a relational position to the surface. In one embodiment, an alignment aid can be a laser and at least one target. Referring to a step 1926, at least one laser is coupled to the handle of the distractor. In one embodiment, the at least one laser is coupled to a feature such as an opening or cavity. In a step 1928, at least one target is coupled to the muscular-skeletal system. In general, the at least one target can be placed overlying the muscular-skeletal system such in a location corresponding to an axis point of the mechanical axis. An axis point on the target aligns to the mechanical axis. The beam from the laser hits the target. The point where the beam hits is compared to the axis point of the target that corresponds to the mechanical axis. The target can have a scale that measures misalignment of the surface to the mechanical axis. As disclosed above, the direction of the laser corresponds to the surface of the muscular- skeletal system.

[00183] In a step 1906, the two surfaces of the muscular-skeletal system are placed in a first position. The misalignment of the surface to the mechanical axis is measured. In a step 1908, the misalignment is corrected if the measurement is outside a predetermined range. In general, data generated by this system can yield significant information on how misalignment affects the muscular-skeletal system. The data can be used to further identify the optimal predetermined range that minimizes the effect of misalignment. In a step 1910, the gap or the space between the inferior and superior surfaces of the spacer is measured. In a step 1912, a force, pressure, or load applied by the two surfaces of the muscular-skeletal system on the distractor is measured. One or more sensors can be placed in the superior or inferior surfaces to measure a parameter such as but not limited to force, pressure, or load. The two surfaces of the muscular-skeletal system apply pressure or force to the superior and inferior surfaces of the spacer and more specifically on at least one sensor on either surface of the distractor. The measurements of steps 1908, 1910, and 1912 are completed with the muscular-skeletal system in the first position. As mentioned above, the first position is typically a geometrically significant position of the muscular-skeletal system that allows comparison to the mechanical axis. The measurement data is transmitted to a processing unit for viewing on a display and for long-term storage. The system allows for real time measurement if and when the muscular-skeletal system is modified with the distractor in place. [00184] The following measurements steps are similar to the measurements in the first position described above. In a step 1916, the two surfaces of the muscular-skeletal system are placed in a second position. The misalignment of the surface to the mechanical axis can be measured in the second position to verify alignment. In a step 1918, the misalignment is corrected in if the measurement is outside a predetermined range. In a step 1920, the gap or the space between the inferior and superior surfaces of the spacer is measured. In a step 1922, a force, pressure, or load applied by the two surfaces of the muscular-skeletal system on the distractor is measured. The measurements of steps 1918, 1920, and 1922 are completed with the muscular-skeletal system in the second position. As mentioned above, the second position is also a geometrically significant position of the muscular- skeletal system that allows comparison to the mechanical axis. The measurement data is transmitted to the processing unit. The system allows for real time measurement in the second position.

[00185] FIG. 20 is an exemplary method 2000 of a disposable orthopedic system in accordance with an exemplary embodiment. The method can be practiced with more or less than the number of steps shown and is not limited to the order shown. In a step 2002, at least one parameter of the muscular- skeletal system is measured with a sensor. As disclosed hereinabove, the sensor provides accurate measurements of parameters such as distance, weight, strain, load, pressure, force wear, vibration, viscosity, and density. In one embodiment, the sensor is a disposable sensor. In a non-limiting example, the disposable sensor is adapted to an orthopedic device such as a tool or implantable component. The sensor is sterilized and placed in a package that maintains sterility. The sensor is typically contaminated with biological material when used to measure the muscular-skeletal system during a surgical procedure. In a step 2004, the sensor is disposed of after use. The sensor is disposed of as biological waste if contaminated by biological material during the procedure. Packaging of a single use device greatly reduces cost, as the housing does not have to withstand repeated cleanings. Moreover, it eliminates the cost of a sterilization process. In a non-limiting example, the sensor is used in orthopedic surgery and more specifically to provide intraoperative measurement during joint implant surgery.

[00186] In a step 2022, the sensor is powered. In one embodiment, the sensor is not powered until it is used. The sensor can have a temporary power source that powers the device for a procedure. A charger can be provided to charge the unit up prior to use. The power source can be internal to the sensor to prevent issues with sterility. The temporary power source can sustain the device for a predetermined period of time that is sufficient for the procedure but prevents reuse of the device. The sensor is in communication with a processing unit. In one embodiment, the processing unit is located external to the sensor. In the surgical example, the processing unit is located outside of the immediate surgical area. For illustration purposes, the processing unit is a microprocessor of a notebook computer.

[00187] In a step 2024, patient information is inputted to the processing unit. The patient information can input through a variety of methods. For example, the information can be typed in, scanned in, downloaded via radio frequency tag, or verbally transmitted, recorded, and converted. The patient information can be displayed on a screen of the notebook computer. The patient information can include personal, medical, and specific information related to the procedure.

[00188] In a step 2026, a reader is coupled to the processing unit. The reader can be wired or wireless. In a step 2028, the reader is used to scan in information pertaining to the procedure. In one embodiment, the reader is used to scan in components of the system such as the sensors, alignment aids, implant components, and other devices prior to use. In a non-limiting example, the information can be used for identification of the specific components (e.g. serial numbers) used during the procedure. The information can be used for billing, patient records, long term monitoring of components, and component recall.

[00189] In a step 2006, the sensor is placed between two surfaces of the muscular-skeletal system. The sensor measures a parameter in proximity to the surfaces of the muscular-skeletal system. In one embodiment, the two surfaces are exposed by incision. For example, the sensor has a small form factor allowing it to be placed in or on a spacer. A spacer separates the two surfaces of muscular-skeletal system. Examples of a spacer are a spacer block or a distractor. In a non-limiting example, a joint of the muscular-skeletal system is exposed. One or more of the joint surfaces can be shaped or prepared by the surgeon. The spacer block or distractor is placed between the joint surfaces of the muscular-skeletal system. The sensor can have an exposed surface that will contact at least one of the two surfaces.

[00190] In a step 2008, a load, force, or pressure applied by the two surfaces on the sensor is measured. For example, the spacer block or distractor distracts the joint of the muscular-skeletal system. A measurement of the load, force, or pressure is measured by the sensor for a spacing or gap. The gap is the distance between the two surfaces of the muscular-skeletal system. In a step 2016, a gap can be varied between the two surfaces of the muscular-skeletal system with the spacer in place. In one embodiment, the gap is varied by a distractor between the two surfaces. The distractor includes a lift mechanism that can increase or decrease a gap between the two surfaces. The sensor can measure one or more parameters at each gap height.

[00191] In a step 2010, the sensor is placed in a cavity of a surface of a spacer. In general, a spacer has a superior and inferior surface. The superior and inferior surfaces are placed between the two surfaces of the muscular- skeletal system. The superior and inferior surfaces come in contact with the two surfaces of the muscular-skeletal system under distraction. In one embodiment, one of the inferior or superior surfaces of the spacer have a cavity or recess for receiving the sensor. The sensor is placed in the cavity exposing a surface of the sensor. The surface of the sensor can be planar with the surface of the spacer. As disclosed above, the spacer can be placed between the two surfaces of the muscular-skeletal system such that the surface of the sensor is in proximity or in contact with one or both of the surfaces. [00192] In a step 2012, the sensor is removed from the cavity or recess. The sensor can have a feature that simplifies removal from the superior or inferior surface of a device. For example, the sensor can have a tab, indentation, or surface feature that allows removal by hand or with a tool. Alternatively, the device in which the sensor is placed can have a mechanism to push the sensor out of the recess. In a step 2014, the sensor is disposed of after being removed from the cavity or recess.

[00193] In a step 2018, an alignment of a surface to a mechanical axis is measured with an alignment aid. In general, at least one of the two surfaces of the muscular-skeletal system has an alignment with a mechanical axis of the muscular-skeletal system. The alignment to the mechanical axis needs to be preserved or corrected during the procedure. Similar to the sensor above, components of the alignment aid are designed for a single use. In one embodiment, the mechanical axis is identified. Similarly, the surface of the muscular-skeletal system is compared to the mechanical axis. The difference between the mechanical axis and surface of the muscular-skeletal system is a measure of the misalignment. Adjustments to the muscular-skeletal system can be performed to reduce misalignment within a predetermined range. In a step 2020, at least one component of the alignment aid is disposed of after the procedure is completed.

[00194] FIG. 21 is an exemplary method 2100 of a disposable orthopedic system in accordance with an exemplary embodiment. The method can be practiced with more or less than the number of steps shown and is not limited to the order shown. In a step 2102, an alignment of a surface to a mechanical axis is measured with an alignment aid. In general, a mechanical axis is identified by the alignment aid. The mechanical axis is then compared to an alignment of one or more surfaces or structures of the muscular-skeletal system. Ideally, the difference or misalignment of the surfaces or structures to the mechanical axis should be within a predetermined range that places the surfaces or structures in an optimal muscular-skeletal kinematic setting.

[00195] In a non-limiting example, targets and more specifically a point on each target correspond to points on the mechanical axis. The targets are coupled to the muscular-skeletal system in proximity to the surfaces of the muscular-skeletal system. The surfaces can be part of structures of the muscular-skeletal system such as bones, muscles, ligament, tendons, and cartilage. The structures corresponding to the surfaces can have a relational positioning in 3D space that relate to the position of the surfaces to each other. In one embodiment, the surface is between the targets. Alternatively, the targets can be placed having an unobstructed path to the surface that allows measurement. The targets can also align having a more complex geometry to represent the mechanical axis. One or more lasers are mounted at a height where a beam from a laser will hit the target unless grossly misaligned. The laser is mounted having a predetermined positional relationship to the plane of the surface. For example, the laser is directed 90 from the plane of the surface corresponding to a direction of the mechanical axis. The targets can have calibration markings to indicate a measure of misalignment. The beam from the laser will hit the point on each target if the plane of the surface is aligned correctly to the mechanical axis. Conversely, the distance from the point on each target is representative of the misalignment. The calibration marking where the beam hits represents the misalignment. Adjustments to the muscular-skeletal system can be performed to reduce misalignment within a predetermined range. In a step 2104, at least one component of the alignment aid is disposed of after the procedure is completed. For example, the targets or lasers that are within the surgical field.

[00196] In one embodiment, the alignment is performed with a distractor between the two surfaces of the muscular-skeletal system. The distractor separates the surfaces of the muscular-skeletal system. In a step 2122, the two surfaces of the muscular-skeletal system are distracted when measuring alignment. The distractor can vary the gap between the two surfaces of the muscular-skeletal system allowing measurements to be taken with varying gap heights.

[00197] In a step 2106, at least one parameter of the muscular-skeletal system is measured with a sensor. As disclosed hereinabove, the sensor provides accurate measurements of parameters such as distance, weight, strain, load, pressure, force wear, vibration, viscosity, and density. In one embodiment, the sensor is a disposable sensor. In a step 2108, the sensor is disposed of after use. The sensor is disposed of as biological waste if contaminated by biological material during the procedure. A disposable sensor provides data for providing quantitative data on the procedure without the large capital expenditure required for traditional measuring equipment.

[00198] In general, data is collected relevant to the procedure. For example, patient information and component information can be collected and stored in an electronic format prior to the procedure being performed. Component information can relate to products used in the procedure such as serial number, date of production, model number, and other related data that identifies the product. In a step 2014, the sensor is powered. In one embodiment, the sensor is not powered until it is used. Once enabled, the sensor can establish communication with a processing unit. The processing unit can be a collection point for information. The processing unit is coupled to memory that can store information locally or send the information to a database. Similarly, the sensor can have information pertaining to the sensor product stored in memory. The sensor can send this information to the processing unit as part of the information collection process. In a step 21 16, patient information is input and provided to the processing unit. The patient information can be input through a variety of methods. For example, the information can be typed in, scanned in, downloaded via radio frequency tag, or verbally transmitted, recorded, and converted. The patient and component information can be displayed on a screen coupled to the processing unit for use by the surgeon or other healthcare providers. The patient information can be encrypted to prevent access by unauthorized people. The patient information can include personal, medical, and specific information related to the procedure. In a step 21 18, a reader is coupled to the processing unit. The reader can be wired or wireless. In a step 2120, the reader is used to scan in information pertaining to the procedure. In one embodiment, the reader is an alternate approach of data collection of components and information. The reader is used to scan and input information displayed on components or packaging of components. The information can be used for billing, patient records, long term monitoring of components, and component recall.

[00199] In a step 21 10, data measured by the sensor is transmitted to the processing unit. The system dynamically measures a parameter of the muscular skeletal system. For example, the system can measure the parameter when the muscular-skeletal system is placed in different positions whereby the position of the surfaces also differs. Another example is modification of the muscular-skeletal system. The sensor reading adjusts as the modification of the muscular-skeletal system changes the parameter being measured. In a step 21 12, the data is displayed in real time on the display. In one embodiment, the sensor transmits data as soon as a measurement is taken. The data is then processed by the processing unit and displayed in a format that aids the surgeon or healthcare worker. Thus, any change in the parameter is stored and displayed while the sensor is enabled.

[00200] FIG. 22 is a diagram 2200 illustrating a data repository and registry for evidence based orthopedics in accordance with at least one exemplary embodiment. In general, the life expectancy of the general population is increasing. It is well known that the body naturally degenerates over time due to the aging process. For example, as we get older there is a natural reduction in bone density and increased wear to the physical joints of the muscular- skeletal system. The situation is exacerbated by being physically active in the work environment, personal life, or both. The consequence of these combined factors is that muscular-skeletal issues are becoming more prevalent. Moreover, these issues can result in a reduction of a quality of life that will impact an increasing percentage of the population. This is evidenced by the high rate of growth of orthopedic surgeries and the implanted artificial orthopedic components.

[00201] As used hereinbelow, the term parameter corresponds to a measurement of the muscular-skeletal system. The measurement can comprise parameters that characterize the muscular-skeletal system such as temperature, pH, distance, weight, strain, pressure, force, wear, vibration, viscosity, and density to name but a few. The measurements can be taken on the natural muscular-skeletal system or artificial components used to replace portions of the system. As discussed herein, the measurements equally apply to natural and artificial components that comprise a muscular-skeletal system.

[00202] A data repository and registry 2214 is a database comprising dynamic data measured from the muscular-skeletal system of patients. In at least one exemplary embodiment, the data repository and registry 2214 comprises orthopedic parameter measurements of more than one patient. Dynamic data corresponds to measurements made to the muscular-skeletal system of the patient. The data measurements occur with little or no human intervention to simplify collection. The dynamic data can comprise measurement by sensors that periodically or by user control measure at least one parameter that is used to characterize the patient orthopedic health or integrity of the muscular-skeletal system (natural or artificial). Thus, in one embodiment, the term dynamic reflects that the measurements are not confined or constrained by time or place. The quantitative measurements can be used to provide continuous feedback by analysis of the data to the patient and healthcare provider. In at least one exemplary embodiment, the quantitative measurements are used to affect the patient outcome, which will be disclosed in more detail below. In a broader sense the data repository and registry 2214 will provide a transition to evidence based medicine in orthopedics. In a further embodiment, data repository and registry 2214 is used to determine efficacy of treatment, early warning of potential problems, improve future orthopedic devices, enhance health care efficiency, reduce orthopedic revisions, and reduce cost of orthopedic procedures.

[00203] In many cases, problems with the muscular-skeletal system for patients 2202 are not short term nor are solutions permanent. For example, an artificial joint or joint component has a life cycle that can measure a decade or more. This life cycle is best illustrated by example. Typically, a patient sustains significant pain and loss of mobility before undergoing an artificial joint implant. The physician and patient monitor the joint. The physician can utilize x-rays or cat-scans of the joint region to determine a source of the problem. At some point in time, a decision is made that it would be in the best interest of the patient to partially or totally replace a joint or joints. In general, a joint replacement is a highly invasive procedure requiring surgery that can include bone and tissue modification. Implant operations to the hip, knee, spine, shoulder, and ankle require interaction with a surgeon, surgical team, operating room and hospital. The patient requires a post-surgical convalescence and cannot immediately use the implanted joint. There are also post surgical complications such as infection and pain that require routine consultation with the surgeon, physician, and health care workers. After recovering from surgery, the patient goes through extensive rehabilitation to acclimate to the artificial joint and use it similarly to a normally functioning natural joint. Long term the patient can require physician visits to check joint status or continued therapy. A worst-case scenario is incorrect installation, joint failure, or un-noticed infection on the artificial surfaces of the joint. Each of these scenarios require substantial rework of the joint and places the patient under severe stress. The cost to the healthcare system to consult, repair, and rehabilitate is a substantial burden that will continue to grow as the number of implants increase. An additional factor is the fact that an increasing number of patients will require replacement of the joint some time in the future

[00204] A further point that should be noted is that each patient of patients 2202 is unique with different physical attributes. More specifically, the geometry of the muscular-skeletal system can have significant variations from patient to patient. Similarly, every surgeon is different and the components developed by the various orthopedic manufacturers will have variations from each other. At this time, orthopedic surgery relies on the skill of the surgeon's subjective knowledge of the procedure for determination on whether the fit of the components is correct. The surgeon often manipulates the joint to "feel" interaction of the implanted components to assess proper fit. Finally, joint wear or joint problems are a function of individual characteristics such as user kinematics, joint mechanical fit, how the joint used, and how much it is used. Thus, joint operation, maintenance, and failure analysis are a complex function of a wide variety of factors of which little or no information exists specifically to the patient. [00205] Patients 2202 are one potential customer of provider 2210 that will benefit from having a history of quantitative measurements of their muscular- skeletal system. Patients 2206 are coupled 2204 for dynamic sensing 2206 at different times and locations. As mentioned previously, the sensors are placed in equipment, tools, and in orthopedic implants that are in proximity or intimate contact to the muscular-skeletal system such that they are coupled 2204 to perform a measurement. In a non-limiting example, parameters of the muscular-skeletal system of patients 2206 are measured by a physician, pre- operatively, intra-operatively, post-operatively, and can be monitored long term. Dynamic sensing 2206 can be periodic or under user control. For example, measurements are made during implantation of an artificial joint to provide quantitative measurements on the installation. Another example is monitoring bone density. Sensors can be implanted in the bone to monitor changes in bone density. Patients 2202 can couple the implanted sensors to a receiver device periodically to take measurements that are sent over the internet to appropriate resources for analysis. Similarly, a physician can have a sensor receiver or sensored equipment in a clinic or office for taking measurements during a patient visit. The ability to generate quantitative data can be used to alert patients 2202 if monitored changes indicate weakening of the bone (e.g. loss of bone density). Therapy can then be provided at an appropriate time to strengthen the bone before a fracture occurs. The measurements can also have significant value in evaluating the clinical efficacy of different types of treatment. Dynamic sensing 2206 can be incorporated into orthopedic devices, surgical tools, implanted, and in monitoring equipment.

[00206] Dynamic sensing 2206 comprises sensors having a form factor that allows integration into equipment, tools, and orthopedic implants. In one embodiment, the sensors are coupled to a processing unit and a display. The sensors are wired or wirelessly coupled to the processing unit. The processing unit can display the measured data in real time on the display and store the measured data in local memory. The processing unit can be coupled to the internet to send encrypted data. In one embodiment, the processing unit and display are separate from the sensors to minimize cost, power, and form factor. The cost to manufacture sensors can be lowered by high volume manufacturing. In one embodiment, volume can be achieved by providing single use sensors that can measure key parameters during installation of orthopedic implants. The surgeon uses the quantitative measurements of the sensors to install an orthopedic implant or to perform a procedure within certain measured predetermined values or ranges. For example, a tighter tolerance in alignment, load, and balance can be achieved through measurement resulting in more consistent procedures. The incremental cost of using the sensors is justified by the reduction in revision and post-operative complications. The sensors are disabled or disposed of after use in a measurement application such as orthopedic implant surgery. Orthopedic procedures and joint implants currently numbers in the millions each year with an increasing annual growth rate. Thus, providing a sustained high volume application that lowers sensor cost. Adoption of the low cost sensing would enable integration into tools and equipment for monitoring/measuring orthopedic health over an extended period of time thereby generating clinical data for an individual patient as well as across the orthopedic industry.

[00207] Dynamic sensing 2206 generates quantitative data on the muscular- skeletal system of patients 2202. The quantitative data is typically a physical measurement that is converted to electronic digital form and sent to a provider 2210 through a wired, optic or wireless coupling 2208. Provider 2210 can provide the sensors for measurement to facilitate dynamic sensing 2206 and data collection. In one embodiment, the data is sent through a wired or wireless connection from the sensors to a processing unit that is part of a computer system or equipment. The processing unit is typically located in proximity to dynamic sensing 2206. The processing unit can analyze and display the measurements in real time to the patient or healthcare provider. The processing unit can immediately send the measurement data of the muscular-skeletal system to data repository and registry 2214 or store it in memory to be sent at an appropriate time. The data can also include personal and medical information. The data is encrypted to maintain patient privacy and deter theft of the data. In the example, the measurement data, personal information, and medical information is transferred through the internet via a coupling 2208. The data is stored in data repository and registry 2214, which is a secure database through a wired, wireless, or optic connection 2212. Provider 2210 has rights to use, license, or sell the quantitative data and manages data repository and registry 2214. In one embodiment, provider 2210 provides the sensors directly or through original equipment manufacturers to measure parameters of the muscular-skeletal system.

[00208] Provider 2210 displays electronic digital information pertaining to measured parameters of the muscular-skeletal system. In one embodiment, the display can be a website. The website can be descriptions of the type of muscular-skeletal information that is available. A customer 2218 interacts with the website through a wired, optic, or wireless coupling 2216. The website can provide options of one or more services provided corresponding to the measured data in data repository and registry 2214. An example of a service is to collate or organize data based on specific criteria or performing an analysis on the data. The customer 2218 can request access to data repository and registry 2214. The request can comprise a service request or access to the measured data for customer proprietary use. The access to data repository and registry 2214 can be restricted or limited based on a number of criteria. As disclosed, patient information and medical history can be stored in data repository and registry. Similarly, the procedure, type of components, serial numbers, and manufacturer of the components can be part of the database. In many cases, the information is proprietary or protected such that access is restricted and specific procedures are put in place to receive the restricted information. As shown, patients 2202 can be customers 2218 and couple to data repository and registry 2214 through coupling 2220. Patients 2202 and physicians of patients would be a select group having access to specific and limited personal and medical information. Conversely, the measured data can be organized and provided anonymously for use by different entities such as hospitals, clinics, government, universities, and manufacturers to name but a few. [00209] FIG. 23 is a diagram 2300 illustrating an orthopedic lifecycle approach to manage orthopedic health based on patient clinical evidence in accordance with at least one exemplary embodiment. The approach utilizes sensors that can measure parameters of the muscular-skeletal system automatically with minimal or no human intervention. The measurements can also be taken under user control. The measured parameters are sent to and stored in a data repository and registry. Measurements on the muscular- skeletal system include artificial components that have been implanted to replace or supplement the existing muscular-skeletal structure. The sensors are incorporated in tools, equipment, or are implanted in or in proximity to the muscular-skeletal system.

[00210] A customer 2302 utilizes measured parameter data of the muscular- skeletal system. In one embodiment, customer 2302 is a patient or health care provider such as a physician or surgeon. The patient or physician can both provide measured parameter data as well as access information from the data repository and registry. In general, quantitative measurements of the muscular-skeletal system are made over an extended period of time, as will be detailed hereinbelow. The measurements can be used to determine orthopedic health status and to indicate potential issues to a patient. In one embodiment, the measurements encompass an entire lifecycle of the patient including orthopedic implants and bone health. Sensored tools and instruments in the patient home, physician office, healthcare facility, hospital, or clinic are used to measure parameters of the muscular-skeletal system in a step 2304 of pre-operative sensing. The parameter measurements are converted to an electronic digital form by the tools or equipment. The measurement data is sent through a medium such as the internet where in a step 2310 of storing information in data repository and registry, the measurements are made part of the database. The measured data can include patient personal and medical information. The quantitative measurements supplement subjective information provided by the patient or physician on an issue of the muscular-skeletal system. In one embodiment, the measurements are displayed to the patient or physician in real time using the tool or equipment. Examples of quantitative measurements are alignment, range of motion, relational positioning, loading, balance, infection, wear, and bone density. This can be used with visual images of the muscular-skeletal system along with subjective information such as pain location to make an effective diagnosis. The measured data can provide an accurate assessment of the status of the muscular-skeletal system prior to any subsequent repair or reconstruction.

[00211] As disclosed above, the muscular-skeletal system can degrade to a point where it can substantial impact a patient quality of life. The decision is often made to repair or replace a portion of the muscular-skeletal system to reduce pain and increase patient mobility. The surgery typically takes place in the operating room of a hospital or clinic. In a step 2308, intra-operative sensing using sensored tools and equipment generates measured data related to the surgery and the installed implant. The sensored tools or equipment convert the measurements to an electronic digital form. The measurement data is sent through a medium such as the internet where in a step 2310 of storing information in data repository and registry, the measurements are made part of the database. The measured data can include patient personal and medical information. The quantitative measurements are displayed during the surgery to aid in the installation. The measurements allow the surgeon to fine tune the installation to be within predetermined ranges that are backed by clinical evidence from the data repository and registry that have proven to reduce negative outcomes. Thus, the parameter measurements supplement a surgeon's subjective skills to ascertain that components are optimally fitted to mimic natural muscular-skeletal operation.

[00212] In general, repair or reconstruction to the muscular-skeletal system includes artificial components. Sensors can be installed in proximity to the muscular-skeletal system, in the muscular-skeletal, or as part of the implanted components during surgery. Implanted sensors can be permanent or temporary. In a step 2308 of monitoring orthopedic health, sensors generate quantitative data on measured parameters of the muscular-skeletal system. Use of the quantitative data in conjunction with the subjective observations of the patient and healthcare providers can increase patient orthopedic health, prevent catastrophic situations, and reduce healthcare costs. In one embodiment, the implanted sensors are powered up temporarily in a manner that allows location independent measurements to be taken. For example, parameter measurements can be taken at the patient's home or at a healthcare provider facility. At home measurements provide an advantage of reducing physician visits while providing a regular status update to the patient and healthcare provider. In a non-limiting example, the patient has a receiver that enables the sensors for measuring parameters. Enabling the sensors comprises providing power and establishing a communication path between sensors and the receiver. The communication can be one-way or both transmit and receive. In one embodiment, the sensors transmit a low power signal. The receiver is placed in proximity to the sensors to receive the low power signal sent by the sensors. The sensors measure parameters of the muscular-skeletal system and convert the measurements to an electronic digital form. The sensors transmit the measurements in electronic digital form to the receiver. In the example, the receiver is coupled to a processing unit. The processing unit can display information to the patient or physician corresponding to the measurements or the status of the muscular-skeletal system. The processing unit sends the measurement data through a medium such as the internet where in a step 2310 of storing information in data repository and registry, the measurements are made part of the database. The measurement data can include patient personal and medical information. A notice, analysis, or report can also be generated by the processing unit or by the data repository and registry. The report can be sent to the appropriate people via a medium such as the internet or wireless network. It should be noted that sensors external to the body can also be used to monitor the muscular-skeletal system. The external sensors can be incorporated into tools or equipment and the measured data sent as disclosed above. Thus, the step 2308 of monitoring orthopedic health has been established that includes periodic quantitative parameter measurements that are used to characterize and assess muscular-skeletal status. This includes operational characteristics of any artificial implanted components. [00213] In one embodiment, the measured data is taken periodically whereby a sufficient sample is generated to allow an analysis to be performed. In a step 2312, a data analysis is performed on the measurement data generated by the patient. The data analysis can encompass many different areas depending on the measurement data and what outcome assessment needs to reviewed. The step 2312 of data analysis can be performed with as new measured data is received. A first example of data analysis is in monitoring infection after installing an artificial joint in a patient. A patient cannot use an artificial joint immediately after surgery. The patient typically convalesces from surgery for a period of time before beginning to use the joint. A post surgical complication such as an infection can be a severe set back to rehabilitation. Infection is often a problem because the artificial surfaces of the joint are ideal areas for bacteria to multiply before the patient is aware of the problem. Common bacterial treatments may have limited effect in preventing escalation of the infection if identified after having established a strong presence in the joint region. In the limit, sepsis can occur resulting in surgical removal of the contaminated artificial joint, local treatment of the infection, and implanting a new joint.

[00214] In the step 2312, measurement in proximity of the joint region can provide information on parameters such as temperature, pH, viscosity, and other factors that are indicators of infection. The analysis is output in an electronic digital form that can be sent via the internet or other medium. The step 2312 of data analysis results in a notification of the patient status being generated. In a step 2316, a healthcare notification status is sent to the appropriate healthcare providers (e.g. physician, surgeon, hospital, clinic, etc...). Similarly, in a step 2314, a patient notification status is sent to the patient. The patient notification status can differ in content from the healthcare notification status. In one embodiment, a single status can be generated to either the healthcare providers or the patient. In a step 2320, the healthcare provider or the patient can be a notification path to the other. For example, the healthcare provider can receive a status based on the data analysis and contact the patient. One outcome is that the step 2312 yields a data analysis that no infection has been detected. The patient can continue the convalescence with regularly scheduled visits. Conversely, an outcome where the step 2312 yields the detection of an infection can result in one or more actions occurring. A step 2318, results in therapeutic treatment using the quantitative data. Early treatment of the infection can eliminate the problem. The patient can be notified in step 2318 to visit the healthcare provider and receive treatment such as antibiotics to eliminate the infection. Alternatively, the implanted device can include antibiotics or a treatment for infection local to the joint surfaces. The implanted device can be enabled to release the treatment to eliminate the infection. In either example, step 2318 results in therapeutic treatment of the infection that is continuously monitored in step 2308. Furthermore, the measurement intervals in the step 2308 can be decreased as part of the therapeutic treatment with the step 2312 of data analysis being performed when the data is received to ensure that the infection is being reduced by the treatment and verified at some point that it has been eliminated.

[00215] A second example of data analysis is in monitoring the joint kinematics after installation of an artificial joint in a patient. The patient undergoes a rehabilitation process that can include substantial physical therapy. Ideally, the patient will have increased joint mobility when compared to the degraded natural joint that was replaced. In the step 2312, measured data in proximity of the joint region can provide information on parameters such as position, relational positioning, alignment, load, and balance that are indicators of the joint kinematics. The measured data is used to assess how the joint is being used and if a potential problem should be addressed. The analysis is output in an electronic digital form that can be sent via the internet or other medium. The step 2312 of data analysis results in a notification of the patient status being generated. In a step 2316, a healthcare notification status is sent to the appropriate healthcare providers. In this example, it could be a physical therapist or physician. Similarly, in a step 2314, a patient notification status is sent to the patient. The patient notification status can differ in content from the healthcare notification status. As discussed previously, a single status can be generated either to the healthcare providers or the patient where and through a step 2320 the other is notified. One outcome is that step 2312 yields a quantitative analysis that the patient kinematics are within an acceptable range. The patient and healthcare provider can receive a notification that the artificial joint is functioning correctly. In the step 2318 a therapeutic treatment could be generated that reinforces the positive outcome by providing a program based on the quantitative data that furthers the positive outcome.

[00216] Conversely, an outcome where the data analysis step 2312 yields a potential problem results in one or more actions occurring. For example, the patient can have an issue with alignment. The data analysis would show that the alignment of the joint is incorrect using positioning and relational positioning data. This would be further corroborated by the load and balance measurements if applicable. The alignment issue could be a result of the installation or the kinematics of the patient. In either case, the result could lead to a shorter joint life span or possible catastrophic failure of the joint. A step 2318, results in therapeutic treatment using the quantitative data. A therapy could be provided based on the analysis that teaches the patient correct posture and exercises that reinforce optimal joint use. The step 2318 could also be an early correction of joint implant before it becomes a problem. The patient can be notified in step 2318 to visit the healthcare provider and receive treatment. Alternatively, the notification can include information on the issue and how to correct the issue. In either example, step 2318 results in therapeutic treatment of the issue that is continuously monitored in step 2308. Furthermore, the measurement intervals in the step 2308 can be decreased as part of the therapeutic treatment with the step 2312 of data analysis being performed when the data is received to ensure that the artificial joint kinematics are correct and or that the issue has been eliminated.

[00217] A third example of the data analysis step 2312 is in monitoring the artificial joint status. Artificial joints have a finite lifetime that is dependent on the implant installation, the implant components, and the patient lifestyle. For example, a person living a very vigorous lifestyle where the muscular-skeletal system and artificial components undergo considerable use is going to age differently from someone having a sedentary existence. A catastrophic artificial joint failure can have both physical and monetary consequences. For example, premature wear can introduce high concentration of metal and plastic particles into the patient body. The foreign material can lead to health issues. Furthermore, premature wear is an indication that the load is not being distributed correctly across a bearing surface of the joint. Typically the problem exacerbates with more wear leading to increased loading issues. This will ultimately lead to complete joint failure. The consequence of a catastrophic failure is complete replacement of the failed joint. A revision is an invasive procedure requiring each component of the artificial joint to be removed and replaced. The patient is placed under considerable stress during the procedure. Moreover, the cost burden of the replacement, which can be significant due to the complexity of the revision, is born individually or in combination with the hospital, physicians, patient, and insurance companies.

[00218] In the step 2312, measured data in proximity of the joint region can provide information on parameters such as position, relational positioning, alignment, load, and balance that are indicators of joint status. In one embodiment, the bearing surface of an artificial joint is monitored by measuring the thickness of the bearing. Wear will occur in a correctly or incorrectly operating joint. Quantitative measurement of the rate of wear and the distribution of the loading in different joint positions can provide significant information as to the joint status and operability. In general, the bearing component is replaced if the bearing surface falls below a predetermined value. The replacement of the bearing component instead of the entire artificial joint can be a much less invasive procedure thereby reducing patient stress, reducing rehabilitation time, and substantially lowering cost. The analysis is output in an electronic digital form that can be sent via the internet or other medium. The step 2312 of data analysis results in a notification of the patient status being generated. In a step 2316, a healthcare notification status is sent to the appropriate healthcare providers. In this example, it could be the patient or physician. Similarly, in a step 2314, a patient notification status is sent to the patient. The patient notification status can differ in content from the healthcare notification status. As discussed previously, a single status can be generated either to the healthcare providers or the patient where and through a step 2320 the other is notified. One outcome is that step 2312 yields a quantitative analysis that the joint status is within predetermined values. The patient and healthcare provider receive a notification that the artificial joint is functioning correctly. In the step 2318 a therapeutic treatment could be generated that further aids the patient to optimize use of the joint based on the quantitative measurements.

[00219] Conversely, an outcome where the data analysis step 2312 yields a potential problem results in one or more actions occurring. For example, the patient can have an issue with the rate of joint wear. The data analysis would show that the patient kinematics is wrong producing excessive wear or that there could be an alignment issue or material issue with the implant itself. This would be further corroborated by other parameter measurements such as load, balance, position, relational positioning and alignment measurements if applicable. In either case, the result could lead to a shorter joint life span or possible catastrophic failure of the joint. A step 2318, results in therapeutic treatment using the quantitative data. A physical therapy could be provided based on the quantitative analysis to correct how the patient is using the joint. Alternatively, the step 2318 can result in a consultation with the physician or surgeon to determine any installation or issues with the materials used to manufacture the joint. The step 2318 could result in an early correction of the joint implant before it becomes a significant problem. In either example, step 2318 results in therapeutic treatment of the issue that is continuously monitored in step 2308. Furthermore, the measurement intervals in the step 2308 can be decreased as part of the therapeutic treatment with the step 2312 of data analysis being performed when the data is received to ensure that the artificial joint kinematics are correct and or that the issue has been eliminated. A further result of the data analysis step 2312 is that the wear of the bearing is outside the predetermined range. A notification is sent to the patient and healthcare provide respectively in steps 2314 and 2316. The treatment in step 2318 is replacement of the bearing.

[00220] A fourth example of the data analysis step 2312 is in monitoring the muscular-skeletal system. In one embodiment, bone density is monitored over the patient lifecycle including prior to any bone issues and measurements taken during a surgical event. Bone density can be monitored by an external system or using one or more sensors that are implanted in bone or proximity to bone. It is well known that bone loss occurs in a large portion of the aging population by osteoporosis. The bone loss or reduction in bone strength can result in a severe injury that greatly impacts patient quality of life and adds significant cost to the healthcare system. A severe injury such as breaking a major bone of the muscular-skeletal system can result in surgery, an extended hospital visit, and a long convalescence. Moreover, it is often difficult to determine the best course of treatment for the patient or the efficacy of the approach taken. Monitoring bone health in a fashion that does not burden healthcare providers but provides clinical data on changes in bone density can have broad implications to the patient and orthopedic health in general.

[00221] In the step 2312, measured data of the bone or muscular-skeletal system is analyzed. In one embodiment, the measured data is collected over an extended period of time and in time increments that allows changes in bone density to be determined. In a non-limiting example, an acoustic signal is sent through the bone and detected after passing through a predetermined bone distance. The acoustic signal can be from an external source or be emitted and received by sensors that are placed in the bone. The time is measured for the acoustic signal to traverse the bone. The measured time corresponds to the bone density. Ideally, the time can be measured very accurately allowing for minute changes in bone density to be monitored. The quantitative measurement of the bone density and the change in bone density can provide significant information as to the health of the muscular-skeletal system. In general, bone health is a consideration if it falls below a predetermined bone density value. Similarly, bone health requires attention if a negative rate of change in bone density is detected. Addressing the issue to maintain or increase bone density brings patient and physician awareness that in combination can prevent a more severe consequence or injury. The analysis is output in an electronic digital form that can be sent via the internet or other medium. The step 2312 of data analysis results in a notification of the patient status being generated. In a step 2316, a healthcare notification status is sent to the appropriate healthcare providers. In this example, it could be the patient, physician, therapist, or muscular-skeletal expert. Similarly, in a step 2314, a patient notification status is sent to the patient. The patient notification status can differ in content from the healthcare notification status. As discussed previously, a single status can be generated either to the healthcare providers or the patient where and through a step 2320 the other is notified. One outcome is that step 2312 yields a quantitative analysis that the joint status is within predetermined values. The patient and healthcare provider receive a notification that the bone density and rate of change of bone density is normal. In the step 2318 a therapeutic treatment could be generated to incorporate supplements to maintain bone density status.

[00222] Conversely, an outcome where the data analysis step 2312 yields a potential problem results in one or more actions occurring. For example, the patient data analysis can show a significant trend in bone density loss. The data analysis provides sufficient time to address the issue before significant bone loss occurs. The bone density could be further corroborated by other parameter measurements once identified to determine cause and potential treatment. Inaction to the quantitative data analysis could result in severe health problems unless addressed in the not too distant future. A step 2318, results in therapeutic treatment using the quantitative data. A combination of supplements, medicine, and physical therapy could be suggested based on the quantitative analysis to correct bone density loss. This analysis can comprise data from a statistically significant sample having similar characteristics from the data repository and registry as well as the individual patient measured data. Alternatively, the step 2318 can result in a consultation with the physician or surgeon to further assess the measured results and design an appropriate therapy. In either example, step 2318 results in therapeutic treatment of the issue that is continuously monitored in step 2308. Furthermore, the measurement intervals in the step 2308 can be decreased as part of the therapeutic treatment with the step 2312 of data analysis being performed when the data is received to determine the efficacy of the treatment. The therapy could be adjusted in a short time span if the improvements are not adequate in slowing or preventing further bone loss. A worst-case scenario of data analysis step 2312 is that the patient bone density is outside an acceptable predetermined range or that the rate of change of bone loss is greater than a predetermined value. A notification is sent to the patient and healthcare providers respectively in steps 2314 and 2316. A diagnosis and course of treatment is then pursued in the step 2318.

[00223] FIG. 24 is an illustration of a sensor 2400 placed in contact between a sensor 2402 and a tibia 2408 for measuring a parameter in accordance with an exemplary embodiment. In general, sensor 2400 is placed in or in proximity to a feature of the skeletal system. In non-limiting example, sensor 2400 is placed within an artificial joint coupled to two or more bones of a skeletal system that move in relation to one another. Embodiments of sensor 2400 are broadly directed to measurement of physical parameters, and more particularly, to evaluating changes in the transit time of a pulsed energy wave propagating through a medium. In-situ measurements during orthopedic joint implant surgery would be of substantial benefit to verify an implant is in balance and under appropriate loading. In one embodiment, the instrument is similar to and operates familiarly with other instruments currently used by surgeons. This will increase acceptance and reduce the adoption cycle for a new technology. The measurements will allow the surgeon to ensure that the replacement implant is within predetermined ranges that maximize working life of the joint and minimize rework. Joint implants will become more consistent from surgeon to surgeon. A further issue is that there is little or no implant data generated from the implant surgery, post-operatively, and long term. Sensor 2400 can provide implant status data to the orthopedic manufacturers and surgeons. Moreover, data generated by direct measurement of the implanted joint itself would greatly improve the knowledge of implanted joint operation and joint wear thereby leading to improved design and materials.

[00224] In at least one exemplary embodiment, an energy pulse is directed within one or more waveguides in sensor 2400 by way of pulse mode operations and pulse shaping. The waveguide is a conduit that directs the energy pulse in a predetermined direction. The energy pulse is typically confined within the waveguide. In one embodiment, the waveguide comprises a polymer material. For example, urethane or polyethylene are polymers suitable for forming a waveguide. In one embodiment, the polymer waveguide can be compressed and has little or no hysteresis in the system. A transit time of an energy pulse through a medium is related to the material properties of the medium. This relationship is used to generate accurate measurements of parameters such as distance, weight, strain, pressure, wear, vibration, and density to name but a few.

[00225] Sensor 2400 can be size constrained by form factor requirements of fitting in a region of a joint of the skeletal system. In one embodiment, sensor 2400 can be fitted in a tool having a surface exposed or coupled for measuring a parameter of the muscular-skeletal system. The mechanical portion of sensor 2400 comprises a stack of a first transducer, a medium, and an acoustically reflective surface. In a non-limiting example, sensor 2400 is used to aid to adjust and balance a replacement knee joint. A knee prosthesis comprises a femoral prosthetic component 2404, an insert, and a tibial prosthetic component 2406. A distal end of sensor 2402 is prepared and receives femoral prosthetic component 2404. Femoral prosthetic component 2404 typically has two condyle surfaces that mimic a natural femur. As shown, femoral prosthetic component 2404 has single condyle surface being coupled to femur 100. Femoral prosthetic component 2404 is typically made of a metal or metal alloy.

[00226] A proximal end of tibia 2408 is prepared to receive tibial prosthetic component 2406. Tibial prosthetic component 2406 is a support structure that is fastened to the proximal end of the tibia and is usually made of a metal or metal alloy. The tibial prosthetic component 2406 also retains the insert in place fixed in position to tibia 2408. The insert is fitted between femoral prosthetic component 2404 and tibial prosthetic component 2406. The insert has at least one bearing surface that is in contact with at least condyle surface of femoral prosthetic component 2404. The condyle surface can move in relation to the bearing surface of the insert such that the lower leg can rotate under load. The insert is typically made of a high wear plastic material that minimizes friction. [00227] In a knee joint replacement process, the surgeon affixes femoral prosthetic component 2404 to the sensor 2402 and tibial prosthetic component 2406 to tibia 2408. The tibial prosthetic component 2406 can include a tray or plate affixed to the planarized proximal end of the tibia 2408. Sensor 2400 is placed between a condyle surface of femoral prosthetic component 2404 and a major surface of tibial prosthetic component 2406. Sensor 2400 can be a trial insert that is subsequently removed after measurements are taken in one or more leg positions. Alternatively, sensor 2400 can be integrated into an insert for taking measurements. The condyle surface contacts a major surface of sensor 2400. The major surface of sensor 2400 approximates a surface of the insert. Tibial prosthetic component 2406 can include a cavity on the major surface that receives and retains sensor 2400 during a measurement process. Tibial prosthetic component 2406 and sensor 2400 has a combined thickness that represents a combined thickness of tibial prosthetic component 2406 and a final insert of the knee joint.

[00228] In one embodiment, two sensors are fitted into two separate cavities of tibial prosthetic component 2406. Each sensor is independent and each measures a respective condyle of sensor 2402. Separate sensors also accommodate a situation where a single condyle is repaired and only a single sensor is used. Alternatively, the electronics can be shared between two sensors to lower cost and complexity the circuitry of which will be disclosed in more detail hereinbelow. The shared electronics can multiplex between each sensor module to take measurements when appropriate. Measurements taken by sensor 2400 aid the surgeon in modifying the absolute loading on each condyle and the balance between condyles. Although shown for a knee implant, sensor 2400 can be used to measure other orthopedic joints such as the spine, hip, shoulder, elbow, ankle, wrist, interphalangeal joint, metatarsophalangeal joint, metacarpophalangeal joints, and others. Alternatively, sensor 2400 can be adapted to orthopedic tools to provide measurements.

[00229] The prosthesis incorporating sensor 2400 emulates the function of a natural knee joint. Sensor 2400 can measure loads or other parameters at various points throughout the range of motion. Data from sensor 2400 is transmitted to a receiving station 2410 via wired or wireless communications. In a first embodiment, sensor 2400 is a disposable system. After using sensor 2400 to optimally fit the joint implant, it can be disposed of after the operation is completed. Sensor 2400 is a low cost disposable system that reduces capital expenditures, maintenance, and accounting when compared to other measurement systems. In a second embodiment, a methodology can be put in place to clean and reuse sensor 2400. In a third embodiment, sensor 2400 can be incorporated in a tool instead of being a component of the replacement joint. The tool can be disposable or be cleaned for reuse. In a fourth embodiment, sensor 2400 can be a permanent component of the replacement joint. Sensor 2400 can be used to provide both short term and long term postoperative data on the implanted joint. The receiving station 2410 can include data processing, storage, or display, or combination thereof and provide real time graphical representation of the level and distribution of the load. Receiving station 2410 can record and provide accounting information of sensor 2400 to an appropriate authority.

[00230] In an intra-operative example, sensor 2400 can measure forces (Fx, Fy, Fz) with corresponding locations and torques (e.g. Tx, Ty, and Tz) on the femoral prosthetic component 2404 and the tibial prosthetic component 2406. The measured force and torque data is transmitted to receiving station 2410 to provide real-time visualization for assisting the surgeon in identifying any adjustments needed to achieve optimal joint pressure and balancing. The data has substantial value in determining ranges of load and alignment tolerances required to minimize rework and maximize longevity of the joint.

[00231] As mentioned previous sensor 2400 can be used for other joint surgeries; it is not limited to knee replacement implant or implants. Moreover, sensor 2400 is not limited to trial measurements. Sensor 2400 can be incorporated into the final joint system to provide data post-operatively to determine if the implanted joint is functioning correctly. Early determination of a problem using sensor 2400 can reduce catastrophic failure of the joint that a patient is unaware of or cannot feel. The problem can often be fixed with a minimal invasive procedure at lower cost and stress to the patient. Similarly, longer term monitoring of the joint can determine wear or misalignment that if detected early can be adjusted for optimal life or replacement of a wear surface with minor surgery thereby extending the life of the implant. In general, sensor 2400 can be shaped such that it can placed or engaged or affixed to or within load bearing surfaces used in any orthopedic applications related to the musculoskeletal system, joints, and tools associated therewith. Sensor 2400 can provide information on a combination of one or more performance parameters of interest such as wear, stress, kinematics, kinetics, fixation strength, ligament balance, anatomic fit and longevity.

[00232] FIG. 25 is a simplified cross-sectional view of a sensing module 2501 (or assemblage) in accordance with an exemplary embodiment. The sensing module (or assemblage) is an electro-mechanical assembly comprising electrical components and mechanical components that when configured and operated in accordance with a sensing mode performs as a positive feedback closed-loop measurement system. The measurement system can precisely measure applied forces, such as loading, on the electromechanical assembly.

[00233] In one embodiment, the electrical components can include ultrasound resonators or transducers, ultrasound waveguides, and signal processing electronics, but are not limited to these. The mechanical components can include biasing springs 2532, spring retainers and posts, and load platforms 2506, but are not limited to these. The electrical components and mechanical components can be inter-assembled (or integrated) onto a printed circuit board 36 to operate as a coherent ultrasonic measurement system within sensing module 2501 and according to the sensing mode. As will be explained hereinbelow in more detail, the signal processing electronics 2510 incorporate edge detect circuitry that detects an edge of a signal after it has propagated through waveguide 2505. The detection initiates the generation of a new pulse by an ultrasound resonator or transducer that is coupled to waveguide 2505 for propagation therethrough. Any change in transit time of a pulse through waveguide 2505 is measured and correlates to a change in material property of waveguide 2505. An external condition being applied to sensing module 2501 such as pressure modifies waveguide 2505 such that a corresponding change in material property is produced. An example is an applied pressure modifies the length of waveguide 2505. Changes in length can be measured by sensing module 2501 and converted to pressure using known characteristics of the medium that waveguide 2505 comprises.

[00234] Sensing module 2501 comprises one or more assemblages 2503 each comprised of one or more ultrasound resonators. As illustrated, waveguide 2505 is coupled between a transducer 2504 and a reflective surface 2530. In general, reflective surface 2530 has a significant acoustic impedance mismatch such that a pulsed energy wave is reflected from surface 2530. Very little or none of the pulsed energy wave is transmitted through reflective surface 2530 due to the acoustic impedance mismatch. In a non- limiting example, reflective surface 2530 can comprise materials such as a polymer, plastic, metal such as steel, or polycarbonate. Transducer 2504 and reflective surface 2530 are affixed to load bearing or contacting surfaces 2506 to which an external condition is applied. In one exemplary embodiment, an ultrasound signal is coupled for propagation through waveguide 2505. The sensing module 2501 is placed, attached to, or affixed to, or within a body, instrument, or other physical system 2507 having a member or members 2508 in contact with the load bearing or contacting surfaces 2506 of the sensing module 2501. This arrangement facilitates translating the parameters of interest into changes in the length or compression or extension of the waveguide or waveguides 2505 within the sensing module or device 2501 and converting these changes in length into electrical signals. This facilitates capturing data, measuring parameters of interest digitizing the data, and subsequently communicating that data through antenna 2534 to external equipment with minimal disturbance to the operation of the body, instrument, appliance, vehicle, equipment, or physical system 2507 for a wide range of applications. [00235] The sensing module 2501 supports three modes of operation: pulse propagation and measurement: reflectance, unidirectional, and bi-directional. These modes can be used as appropriate for each individual application. In unidirectional and bi-directional modes, a chosen ultrasound resonator or transducer is controlled to emit pulses of ultrasound waves into the ultrasound waveguide and one or more other ultrasound resonators or transducers are controlled to detect the propagation of the pulses of ultrasound waves at a specified location or locations within the ultrasound waveguide. In at least one exemplary embodiment, reflectance also described as pulse-echo mode is utilized. Pulse-echo mode uses a single transducer to emit pulsed energy waves into waveguide 2505 and the single transducer subsequently detects pulses of echo waves after reflection from a selected feature or termination of the waveguide. In a non-limiting example, the pulsed energy wavers are ultrasound waves. In pulse-echo mode, echoes of the pulses can be detected by controlling the actions of an emitting ultrasound resonator or transducer to alternate between emitting and detecting modes of operation. Pulse and pulse- echo modes of operation may require operation with more than one emitted pulsed energy waves propagating within the waveguide at equilibrium.

[00236] Many parameters of interest within physical systems or bodies can be measured by evaluating changes in the transit time of energy pulses. The type and frequency of the energy pulse is determined by factors such as distance of measurement, medium in which the signal travels, accuracy required by the measurement, form factor of system, power constraints, and cost. In the non-limiting example, pulses of ultrasound energy provide accurate markers for measuring transit time of the pulses within waveguide 2505. In general, an ultrasonic signal is an acoustic signal having a frequency above the human hearing range (e.g. > 20KHz). In one embodiment, a change in transit time of an ultrasonic energy pulse corresponds to a difference in the physical dimension of the waveguide from a previous state. For example, a force or pressure applied across the knee joint compresses waveguide 2505 to a new length that is related to transit time of the energy pulse When integrated as a sensing module and inserted or coupled to a physical system or body, these changes are directly correlated to the physical changes on the system or body and can be readily converted to a pressure or a force.

[00237] FIG. 26 is an exemplary assemblage 2600 for illustrating reflectance and unidirectional modes of operation. It comprises one or more transducers 2602, 2604, and 2606, one or more waveguides 2614, and one or more optional reflecting surfaces 2616. The assemblage 2600 illustrates propagation of ultrasound waves 2618 within the waveguide 2614 in the reflectance and unidirectional modes of operation. Either ultrasound resonator or transducer 2602 and 2604 in combination with interfacing material or materials 2608 and 2610 can be selected to emit ultrasound waves 2618 into the waveguide 2614. An interfacing material 2612 is an interface between transducer 2606 and waveguide 2614.

[00238] In unidirectional mode, either of the ultrasound resonators or transducers for example 2602 is controlled to emit ultrasound waves 2618 into the waveguide 2614. The other ultrasound resonator or transducer 2604 is controlled to detect the ultrasound waves 2618 emitted by the emitting ultrasound resonator 2602 or transducer.

[00239] In reflectance mode, the ultrasound waves 2618 are detected by the emitting ultrasound resonator or transducer after reflection 2620 from the opposite end of the waveguide 2614 by a reflective surface, interface, or body at the opposite end of the waveguide. In this mode, either of the ultrasound resonators or transducers 2602 or 2604 can be selected to emit and detect ultrasound waves.

[00240] Additional reflection features 2616 can be added within the waveguide structure to reflect ultrasound waves. This can support operation in a combination of unidirectional and reflectance modes. In this mode of operation, one of the ultrasound resonators, for example resonator 2602 is controlled to emit ultrasound waves 2618 into the waveguide 2614. Another ultrasound resonator or transducer 2606 is controlled to detect the ultrasound waves 2618 emitted by the emitting ultrasound resonator 2602 (or transducer) subsequent to their reflection by reflecting feature 2616. [00241 ] FIG. 27 is an exemplary assemblage 2700 that illustrates propagation of ultrasound waves 2710 within the waveguide 2706 in the bidirectional mode of operation of this assemblage. In this mode, the selection of the roles of the two individual ultrasound resonators (2702, 2704) or transducers affixed to interfacing material 2720 and 2722 are periodically reversed. In this mode the transit time of ultrasound waves propagating in either direction within the waveguide 2706 can be measured. This can enable adjustment for Doppler effects in applications where the sensing module 2708 is operating while in motion 2716. Furthermore, this mode of operation helps assure accurate measurement of the applied load, force, pressure, or displacement by capturing data for computing adjustments to offset this external motion 2716. An advantage is provided in situations wherein the body, instrument, appliance, vehicle, equipment, or other physical system 2714, is itself operating or moving during sensing of load, pressure, or displacement. Similarly, the capability can also correct in situation where the body, instrument, appliance, vehicle, equipment, or other physical system, is causing the portion 2712 of the body, instrument, appliance, vehicle, equipment, or other physical system being measured to be in motion 2716 during sensing of load, force, pressure, or displacement. Other adjustments to the measurement for physical changes to system 2714 are contemplated and can be compensated for in a similar fashion. For example, temperature of system 2714 can be measured and a lookup table or equation having a relationship of temperature versus transit time can be used to normalize measurements. Differential measurement techniques can also be used to cancel a common factor as is known in the art.

[00242] The use of waveguide 2706 enables the construction of low cost sensing modules and devices over a wide range of sizes, including highly compact sensing modules, disposable modules for bio-medical applications, and devices, using standard components and manufacturing processes. The flexibility to construct sensing modules and devices with very high levels of measurement accuracy, repeatability, and resolution that can scale over a wide range of sizes enables sensing modules and devices to the tailored to fit and collect data on the physical parameter or parameters of interest a wide range of medical and non-medical applications.

[00243] For example, sensing modules or devices may be placed on or within, or attached or affixed to or within, a wide range of physical systems including, but not limited to instruments, appliances, vehicles, equipments, or other physical systems as well as animal and human bodies, for sensing the parameter or parameters of interest in real time without disturbing the operation of the body, instrument, appliance, vehicle, equipment, or physical system.

[00244] In addition to non-medical applications, examples of a wide range of potential medical applications may include, but are not limited to, implantable devices, modules within implantable devices, modules or devices within intraoperative implants or trial inserts, modules within inserted or ingested devices, modules within wearable devices, modules within handheld devices, modules within instruments, appliances, equipment, or accessories of all of these, or disposables within implants, trial inserts, inserted or ingested devices, wearable devices, handheld devices, instruments, appliances, equipment, or accessories to these devices, instruments, appliances, or equipment. Many physiological parameters within animal or human bodies may be measured including, but not limited to, loading within individual joints, bone density, movement, various parameters of interstitial fluids including, but not limited to, viscosity, pressure, and localized temperature with applications throughout the vascular, lymph, respiratory, and digestive systems, as well as within or affecting muscles, bones, joints, and soft tissue areas. For example, in orthopedic applications this may include, but is not limited to, load bearing prosthetic components, or provisional or trial prosthetic components for, but not limited to, surgical procedures for knees, hips, shoulders, elbows, wrists, ankles, and spines; any other orthopedic or musculoskeletal implant, or any combination of these.

[00245] FIG. 28 is an exemplary cross-sectional view of a sensor element 2800 to illustrate changes in the propagation of ultrasound waves 2814 with changes in the length of a waveguide 2806. An external force 2808 compresses waveguide 2806 thereby changing the length of waveguide 2806. Sensing circuitry (not shown) measures propagation characteristics of ultrasonic signals in the waveguide 2806 to determine the change in the length of the waveguide 2806. These changes in length change in direct proportion to the parameters of interest thus enabling the conversion of changes in the parameter or parameters of interest into electrical signals.

[00246] As illustrated, external force 2808 compresses waveguide 2806 and pushes the transducers 2802 and 2804 closer to one another by a distance 2810. This changes the length 2812 of the waveguide propagation path between transducers 2802 and 2804. Depending on the operating mode, the sensing circuitry measures the change in length of the waveguide 2806 by analyzing characteristics of the propagation of ultrasound waves within the waveguide.

[00247] One interpretation of FIG. 28 illustrates waves emitting from transducer 2802 at one end of waveguide 2806 and propagating to transducer 2804 at the other end of the waveguide 2806. The interpretation includes the effect of movement of waveguide 2806 and thus the velocity of waves propagating within waveguide 2806 (without changing shape or width of individual waves) and therefore the transit time between transducers 2802 and 2804 at each end of the waveguide. The interpretation further includes the opposite effect on waves propagating in the opposite direction and is evaluated to estimate the velocity of the waveguide and remove it by averaging the transit time of waves propagating in both directions in turns, not simultaneously.

[00248] Changes in the parameter or parameters of interest are measured by measuring changes in the transit time of energy pulses or waves within the propagating medium. Closed loop measurement of changes in the parameter or parameters of interest is achieved by modulating the repetition rate of energy pulses or the frequency of energy waves as a function of the propagation characteristics of the elastic energy propagating structure. [00249] These measurements may be implemented with an integrated wireless sensing module or device having an encapsulating structure that supports sensors and load bearing or contacting surfaces and an electronic assemblage that integrates a power supply, sensing elements, energy transducer or transducers and elastic energy propagating structure or structures, biasing spring or springs or other form of elastic members, an accelerometer, antennas and electronic circuitry that processes measurement data as well as controls all operations of ultrasound generation, propagation, and detection and wireless communications. The electronics assemblage also supports testability and calibration features that assure the quality, accuracy, and reliability of the completed wireless sensing module or device.

[00250] FIG. 29 is an exemplary block diagram 2900 of a measurement system in accordance with one embodiment. The measurement system comprises components of the sensing module 2501 shown in FIG. 25. The measurement system includes a sensing assemblage 2902 and a pulsed system 2904 that detects energy waves 2906 in one or more waveguides 2505 of the sensing assembly 2902. A pulse 2920 is generated in response to the detection of energy waves 2906 to initiate a propagation of a new pulse in waveguide 2505.

[00251] The sensing assembly 2902 comprises transducer 2504, reflective surface 2530, and a waveguide 2505 (or energy propagating structure). In a non-limiting example, sensing assemblage 2902 is affixed to load bearing or contacting surfaces. External forces or conditions for measurement are applied to the contacting surfaces. In at least one exemplary embodiment, the external forces 2908 compress the waveguide 2505 thereby changing the length of the waveguide 2505 depending on the force applied thereon. Similarly, transducer 2504 and reflective surface 2530 move closer together under compression. In the reflected or pulsed echo mode, a transit time 2910 of a pulsed energy wave comprises a time period indicated by arrow 2922 of the pulsed energy wave moving from transducer 2504 through waveguide 2505 to reflective surface 2530 plus the echo time period indicated by arrow 2924 comprising a reflected pulse energy wave moving from reflective surface 2530 through waveguide 2505 back to transducer 2504. Thus, a change in length of waveguide 2505 affects the transit time 2910 of energy waves 2906 comprising the transmitted and reflected path. The pulsed system 2904 in response to these physical changes will detect each energy wave sooner (e.g. shorter transit time) and initiate the propagation of new pulses associated with the shorter transit time. As will be explained below, this is accomplished by way of pulse system 2904 in conjunction with the pulse circuit 2912, the mode control 2914, and the edge detect circuit 2916.

[00252] Notably, changes in the waveguide 2505 (energy propagating structure or structures) alter the propagation properties of the medium of propagation (e.g. transmit time 2910). A pulsed approach reduces power dissipation allowing for a temporary power source such as a battery or capacitor to power the system during the course of operation. In at least one exemplary embodiment, a pulse is provided to transducer 2504 coupled to a first surface of waveguide 2505. Transducer 2504 generates a pulsed energy wave 2906 coupled into waveguide 2505. In a non-limiting example, transducer 2504 is a piezo-electric device capable of transmitting and receiving acoustic signals in the ultrasonic frequency range. Transducer 2504 is toggled between an emitting mode to emit a pulsed energy wave into waveguide 2505 and a receiving mode to generate an electrical signal corresponding to a reflected pulsed energy wave.

[00253] In a start up mode, transducer 2504 is enabled for receiving the reflected pulsed energy wave after generating one or more pulsed energy waves and delivering them into waveguide 2505. Upon receiving the reflected pulsed energy wave, transducer 2504 generates an electrical signal corresponding to the reflected pulsed energy wave. The electrical signal output by transducer 2504 is coupled to edge detect circuit 2916. In at least one exemplary embodiment, edge detect circuit 2916 detects a leading edge of the electrical signal output by transducer 2504 (e.g. the propagated reflected energy wave 2906). The detection of the reflected propagated pulsed signal occurs earlier (due to the length/distance reduction of waveguide 2505) than a prior signal due to external forces 2908 being applied to compress sensing assemblage 2902. Pulse circuit 2912 generates a new pulse in response to detection of the propagated and reflected pulsed signal by edge detect circuit 2916. Transducer 2504 is then enabled to generate a new pulsed energy wave. A pulse from pulse circuit 2912 is provided to transducer 2504 to initiate a new pulsed sequence. Thus, each pulsed sequence is an event of pulse propagation, pulse detection and subsequent pulse generation that initiates the next pulse sequence.

[00254] The transit time 2910 of the propagated pulse is the total time it takes for a pulsed energy wave to travel from transducer 2504 to reflecting surface 2530 and from reflecting surface 2530 back to transducer 2504. There is delay associated with each circuit described above. Typically, the total delay of the circuitry is less than the propagation time of a pulsed signal through waveguide 2505. Multiple pulse to pulse timings can be used to generate an average time period when change in external forces 2908 occur relatively slowly in relation to the pulsed signal propagation time. The digital counter 2918 in conjunction with electronic components counts the number of propagated pulses to determine a corresponding change in the length of the waveguide 2505. These changes in length change in direct proportion to the external force thus enabling the conversion of changes in parameter or parameters of interest into electrical signals.

[00255] In at least one exemplary embodiment, pulsed system 2904 in conjunction with one or more sensing assemblages 2902 are used to take measurements on a muscular-skeletal system. In a non-limiting example, sensing assemblage 2902 is placed between a femoral prosthetic component and tibial prosthetic component to provide measured load information that aids in the installation of an artificial knee joint. The measurements can be made in extension and in flexion. Assemblage 2902 is used to measure the condyle loading to determine if it falls within a predetermined range. Based on the measurement, the surgeon can select the thickness of the insert such that the measured loading with the final insert in place will fall within the predetermined range. Soft tissue tensioning can be used by a surgeon to further optimize the force or pressure. Similarly, two assemblages 2902 can be used to measure both condyles simultaneously or multiplexed. The difference in loading (e.g. balance) between condyles can be measured. Soft tissue tensioning can be used to reduce the force on the condyle having the higher measured loading to reduce the measured pressure difference between condyles.

[00256] One method of operation holds the number of pulsed energy waves propagating through waveguide 2505 as a constant integer number. A time period of a pulsed energy wave corresponds to the time between the leading pulse edges of adjacent pulsed energy waves. A stable time period or a period of equilibrium is one in which the time period changes very little over a number of pulsed energy waves. This occurs when conditions that affect sensing assemblage 2902 stay consistent or constant. Holding the number of pulsed energy waves propagating through waveguide 2505 to an integer number is a constraint that forces a change in the time between pulses when the length of waveguide 2505 changes. The resulting change in time period of each pulsed energy wave corresponds to a change in aggregate pulse periods that can be captured using digital counter 2918 as a measurement of changes in external forces or conditions 2908.

[00257] In an alternate embodiment, the repetition rate of pulsed energy waves 2906 emitted by transducer 2504 can be controlled by pulse circuit 2912. The operation remains similar where the parameter to be measured corresponds to the measurement of the transit time 2910 of pulsed energy waves 2906 within waveguide 2505 as described above. It should be noted that an individual ultrasonic pulse can comprise one or more energy waves with a damping wave shape as shown. The pulsed energy wave shape is determined by the electrical and mechanical parameters of pulse circuit 2912, interface material or materials, where required, and ultrasound resonator or transducer 2504. The frequency of the pulsed energy waves is determined by the response of the emitting ultrasound resonator 2504 to excitation by an electrical pulse 2920. The mode of the propagation of the pulsed energy waves 2906 through waveguide 2505 is controlled by mode control circuitry 2914 (e.g., reflectance or uni-directional). The detecting ultrasound resonator or transducer may either be a separate ultrasound resonator or the emitting resonator or transducer 2504 depending on the selected mode of propagation (reflectance or unidirectional).

[00258] In general, accurate measurement of physical parameters is achieved at an equilibrium point having the property that an integer number of pulses are propagating through the energy propagating structure at any point in time. Measurement of changes in the "time-of-flight" or transit time of ultrasound pulses within a waveguide of known length can be achieved by modulating the repetition rate of the ultrasound pulses as a function of changes in distance or velocity through the medium of propagation, or a combination of changes in distance and velocity, caused by changes in the parameter or parameters of interest

[00259] It should be noted that ultrasound energy pulses or waves, the emission of ultrasound pulses or waves by ultrasound resonators or transducers, transmitted through ultrasound waveguides, and detected by ultrasound resonators or transducers are used merely as examples of energy pulses, waves, and propagation structures and media. Other embodiments herein contemplated can utilize other wave forms, such as, light.

[00260] Measurement by pulsed system 2904 and sensing assemblage 2902 enables high sensitivity and signal-to-noise ratio as the time-based measurements are largely insensitive to most sources of error that may influence voltage or current driven sensing methods and devices. The resulting changes in the transit time of operation corresponds to frequency, which can be measured rapidly, and with high resolution. This achieves the required measurement accuracy and precision thus capturing changes in the physical parameters of interest and enabling analysis of their dynamic and static behavior.

[00261] FIG. 30 is a measurement system operating in pulsed echo mode with digital output according to one embodiment. In particular, it illustrates a measurement sequence comprising pulse emission into a medium, propagation through the medium, reflection, detection of the reflected propagated signal, and measurement of the transit time. The medium is subjected to the parameter to be measured such as weight, strain, pressure, wear, vibration, viscosity, and density. In a non-limiting example, pressure is a parameter used to illustrate the measurement system. Pressure is applied across the medium in a direction of the traversed path of the waveform. The pressure compresses the medium thereby changing the length of the medium. In general, reducing the length of the traversed path by the pulse correspondingly lowers the transit time of the waveform. The transit time is correlated to a pressure measurement in conjunction with the material properties of the medium. In one embodiment, the transit time is converted to a length, or change in length, of the medium at the time of the measurement. The material properties of the medium are known where a mathematical function or look up table correlates force or pressure to the measured length or change in length. Further accuracy can be obtained by including any other external conditions (ex. temperature) that affect the medium at the time of the measurement.

[00262] The system allows for more than one than one measurement to be taken. In one embodiment, a new measurement sequence is initiated upon detecting a propagated waveform. A pulse is generated upon detection of the propagated pulsed energy wave. The pulse is provided to transducer 2504 to emit a new pulsed energy wave into the medium. The process continues until stopped under user control. The system provides the benefit of very low power usage because as little as a single pulsed energy wave can be used to make a measurement whereas a continuous wave measurement requires a continuous signal to be maintained. Reducing the pulse width can also lower power usage since only the leading edge is being detected. A further benefit is that in a low power application a high energy pulsed wave can be used to compensate for attenuation in the medium or a significant distance of travel. Although attenuated by the medium, the measurement can be highly accurate and the signal detectable. The high-energy pulse would be difficult to sustain in low power environment (e.g. battery or temporary power source) but in pulsed mode can be used to make measurements that would be difficult using other methodologies. [00263] Referring to FIG. 25, in pulse echo mode of operation, the sensing module 2501 measures a time of flight (TOF) between when a pulsed energy wave is transmitted by transducer 2504 into waveguide 2505, reflected, and received by transducer 2504. Transducer 2504 generates a signal corresponding to the received reflected pulse. The time of flight determines the length of the waveguide propagating path, and accordingly reveals the change in length of the waveguide 2505. In another arrangement, differential time of flight measurements can be used to determine the change in length of the waveguide 2505. A pulse can comprise a pulse of one or more waves. The waves may have equal amplitude and frequency (square wave pulse) or they may have different amplitudes, for example, decaying amplitude (trapezoidal pulse) or some other complex waveform. The pulsed system detects an edge of each pulse propagating through the waveguide and holds the delay between each edge constant under stable operating conditions.

[00264] A pulse method facilitates separation of ultrasound frequency, damping waveform shape, and repetition rate of pulses of ultrasound waves. Separating ultrasound frequency, damping waveform shape, and repetition rate enables operation of ultrasound transducers at or near resonance to achieve higher levels of conversion efficiency and power output thus achieving efficient conversion of ultrasound energy. This may enable, but is not limited to, lower power operation for ultra-low power devices.

[00265] Referring back to FIG. 30, the operation of the measurement system will be described utilizing the timing diagram of FIG. 31. In general, one or more pulsed energy waves can be propagating through the medium during a measurement. In a non-limiting example, a measurement sequence comprises a single ultrasonic pulsed energy wave emitted into propagating structure or waveguide 2505, propagation through waveguide 2505, reflection off a reflecting surface 2530, propagation through waveguide 2505, and detection by transducer 2504. The forward propagation of a pulsed energy wave from transducer 2504 to reflecting surface 2530 is indicated by arrow 3077. A return propagation of a reflected pulsed energy wave is indicated by arrow 3079. In at least one exemplary embodiment, the system maintains an integer number of pulses within waveguide 2505 while the time period of a pulsed energy wave varies due to external forces or conditions 3032 applied to the propagating medium. In one embodiment, external forces or conditions 3032 are applied to lengthen or shorten a propagating path of the pulsed energy waves. The time period of each pulsed energy wave remains constant when multiple measurements are taken and conditions 3032 do not vary.

[00266] The measurement system comprises a pulse circuit 3008, a switch 3004, an amplifier 3012, a transducer 2504, a waveguide 2505, a reflecting surface 2530, an amplifier 3020, a switch 3028, and a digital logic circuit 3075. Control circuitry 606 can be part of digital logic circuit 3075. Switch 3004 has a first terminal coupled to an output 3010 of pulse circuit 3008, a control terminal, and a second terminal. Amplifier 3012 has an input coupled to the second terminal of switch 3004, a control output 3080, and an output. Transducer 2504 has a terminal coupled to the output of amplifier 3012 and is operatively coupled for emitting a pulsed energy wave into waveguide 2505 at a first location of waveguide 2505. Reflecting surface 2530 is operatively coupled for reflecting a pulsed energy wave propagated through waveguide 2505 at a second location. Reflecting surface 2530 is not transmissive to pulsed energy waves and typically represents a high acoustic mismatch that promotes reflectivity. Thus, transducer 2504 both emits pulsed energy waves into waveguide 2505 and generates a signal corresponding the received reflected pulsed energy waves at the first location. Amplifier 3020 has an input coupled the terminal of transducer 2504, a control input 3082 coupled to the control output 3080 of amplifier 3012, and an output. Switch 3028 has a first terminal coupled to the output of amplifier 3020, a control terminal, and a second terminal coupled to the input of amplifier 3012. Digital logic circuit 3075 has one or more outputs for initiating a sensing sequence, taking multiple measurements, and measuring the transit time or time period of propagated pulsed energy waves.

[00267] Transducer 2504 has two modes of operation. Transducer 2504 emits a pulsed energy wave into medium 2505. Transducer 2504 is then enabled to receive and generate a signal corresponding to a reflected pulsed energy wave reaching the second location. Upon receiving the reflected pulse energy wave, transducer 2504 converts the reflected pulsed energy wave into analog pulses 3018 of electrical waves having the same repetition rate. Transducer 2504 then is enabled to emit a new pulsed energy wave. Thus, transducer 2504 is used in a repeating sequence of emitting and detecting. The analog pulses 3018 output by transducer 2504 (in the reflected pulse receiving mode) may need amplification.

[00268] The timing diagram of FIG. 31 will be referred to in description of pulse echo mode operation of the measurement system hereinbelow. In particular, pressure or force is measured as an illustration of a parameter being measured. Control circuit 3006 initiates a measurement sequence by providing control signals to switches 3004 and 3028 respectively indicated by closed position 3142 and open position 3140 of FIG. 31. Pulse circuit 3008 can then be enabled to provide one or more ultrasonic pulsed energy waves to amplifier 3012. In the example disclosed above, a control input 3002 couples to control circuit 3006. Control circuit 3006 provides a signal to enable pulse circuit 3008 to provide at least one pulse to initiate one or more measurements. In FIG. 31 , pulse circuit 3008 provides pulses 3102, 3104, 3106, and 3108 to amplifier 3012. It should be noted that pulses 3104, 3106, and 3108 are not needed if pulse 3102 results in a detection and subsequent pulse generation by amplifier 3020. In general, an integer number of pulses can be propagating through waveguide 2505. In the example, a single pulse propagates through waveguide 2505 at any point in time. The time period of the pulsed energy wave is equal to or less than the transit time to traverse waveguide 2505 twice.

[00269] Amplifier 3012 receives the pulses from pulse circuit 3008 and provides analog pulses 3014 to the terminal of transducer 2504. In at least one exemplary embodiment amplifier 3012 comprises a digital driver 3042 and matching network 3044. Digital driver 3042 and matching network 3044 transforms the digital output (e.g. square wave) of pulse circuit 3008 into shaped or analog pulses 3014 that are modified for emitting transducer 2504. The repetition rate of pulses 3014 is equal to the repetition rate of the pulses provided by pulse circuit 3008. Amplifier 3012 drives transducer 2504 with sufficient power to generate energy waves 3016. In a non-limiting example, energy waves 3016 propagating through waveguide 2505 are ultrasound waves.

[00270] In general, ultrasound transducers naturally resonate at a predetermined frequency. Providing a square wave or digital pulse to the terminal of emitting transducer 2504 could yield undesirable results. Digital driver 3042 of amplifier 3012 drives matching network 3044. Matching network 3044 is optimized to match an input impedance of emitting transducer 2504 for efficient power transfer. In at least one exemplary embodiment, digital driver 3042, matching network 3044, solely, or in combination shapes or filters pulses provided to the input of amplifier 3012. The waveform is modified from a square wave to analog pulse 3014 to minimize ringing and to aid in the generation of a damped waveform by emitting transducer 2504. The rounded pulses illustrated in FIG. 31 at the output of amplifier 3012 are representative of the pulse modification. In one embodiment, a pulsed energy wave emitted into waveguide 2505 can ring with a damped envelope that affects signal detection, which will be disclosed in more detail below.

[00271 ] The one or more pulsed energy waves 3016 are emitted at a first location of waveguide 2505, propagate through energy propagating structure or waveguide 2505, are reflected by reflecting surface 2530, propagate back towards the first surface, and then are detected by transducer 2504 at the first location. In the example, a pulsed energy wave 3120 of FIG. 31 is generated by transducer 2504 from pulse 3102 output by pulse circuit 3008. Pulsed energy wave 3120 propagates in waveguide 2505 from the first location towards reflecting surface 2530 and back to transducer 2504 after being reflected. The pulsed energy wave 3120 of FIG. 31 is detected by transducer 2504 upon reaching the first location. Transducer 2504 generates a signal corresponding to the received pulsed energy wave 3120 that is coupled to the input of amplifier 3020. In general, detecting transducer 2504 converts propagated pulsed energy waves 3016 into pulses 3018 of electrical waves having the same repetition rate. The signal output of detecting transducer 2504 may need amplification.

[00272] Amplifier 3020 comprises pre-amplifier 3022 and edge-detect receiver 3024. In a first mode, amplifier 3020 receives a control signal from amplifier 3012 to blank, disable, or decouple the output of amplifier 3020 when transducer 2504 is emitting a pulsed energy wave into waveguide 2505. The control signal is provided from control output 3080 of amplifier 3012 to control input 3082 of amplifier 3020. In a second mode, the control signal from amplifier 3012 enables the output for providing a signal to transducer 2504. Pre-amplifier 3022 receives and amplifies analog pulses 3018 from transducer 2504 in the second mode. Amplifier 3020 toggles between the first and second modes of operation depending on whether transducer 2504 is emitting or receiving a pulsed energy wave. Edge-detect receiver 3024 detects an edge of each arriving pulse corresponding to each propagated pulsed energy wave 3016 through waveguide 2505. As mentioned previously, each pulsed energy wave can be a ringing damped waveform. In at least one exemplary embodiment, edge-detect receiver 3024 detects a leading edge of each arriving pulse 3018. Edge-detect receiver 3024 can have a threshold such that signals below the threshold cannot be detected. Edge-detect receiver 3024 can include a sample and hold that prevents triggering on subsequent edges of a ringing damped signal. The sample and hold can be designed to "hold" for a period of time where the damped signal will fall below the threshold but less than the time period between adjacent pulses under all operating conditions.

[00273] Amplifier 3020 generates a digital pulse 3026 that is triggered by each leading edge of each propagated pulsed energy waves 3016 detected by transducer 2504. The first digital pulse output by amplifier 3020 is indicated by pulse 31 10 of FIG. 31. Pulse 31 10 corresponds to pulsed energy wave 3122 of FIG. 31. In a non-limiting example, control circuitry 3006 responds to the first digital pulse output from amplifier 3020 after starting a measurement sequence by closing switch 3028 and opening switch 3004. The control signals for switches 3004 and 3028 are respectively indicated by open 3144 and closed 3148. Pulses 3104, 3106, and 3108 of FIG. 31 output by pulse circuit 3008 are not received by amplifier 3012 after switch 3004 opens.

[00274] A positive feedback closed loop circuit is then formed that couples a pulse generated by amplifier 3020 to the input of amplifier 3012 thereby sustaining a sequence comprising: a pulsed energy wave emission into waveguide 2505 at the first location; propagation of the pulsed energy wave 3016 through waveguide 2505; reflection of the pulsed energy wave 3016 by reflecting surface 2530 at the second location; propagation of the pulse energy wave 3016 back to the first location; detection and signal generation of the pulsed energy wave 3016 by transducer 2504; and generation of digital pulse 3026 by amplifier 3020. Each digital pulse 3026 is of sufficient length to sustain the pulse behavior of the measurement system when it is coupled back to amplifier 3012 through switch 3028. Alternatively, a measurement process can be stopped by opening switches 3004 and 3028 such that no pulses are provided to amplifier 3012 and thereby to transducer 2504. In general, circuitry of the measurement system that dissipates power can be turned off or put into a sleep mode when decoupled from amplifier 3012 by switches 3004 and 3028.

[00275] In one embodiment, the delay of amplifiers 3020 and 3012 is small in comparison to the propagation time of a pulsed energy wave through waveguide 2505. In an equilibrium state, an integer number of pulses of energy waves 3016 in waveguide 2505 have equal time periods and transit times when propagating through energy propagating structure or waveguide 2505. In general, as one energy pulse wave is detected by transducer 2504, a new energy pulse wave is emitted into waveguide 2505 (after some finite delay). Transit time 3154 is the time required for a pulsed energy wave to traverse waveguide 2505 twice. A time period 3152 is the time between pulses. In the single pulse example, time period 3152 and transit time 3154 are similar or equal. The time period 3152 is less than the transit time 3154 when more than one pulsed energy waves reside within waveguide 2505 simultaneously. Similarly, a time period 3156 of pulses output by amplifier 3020 are equal to the time period 3152 of corresponding pulsed energy waves. Movement or changes in the physical properties of the energy propagating structure or waveguide 2505 change the transit time 3030 of energy waves 3016. This disrupts the equilibrium thereby changing when a pulsed energy wave is detected by edge-detect receiver 3024. A transit time 3154 is reduced should external forces 3032 compress waveguide 2505 in the direction of propagation of energy waves 3016. Conversely, the transit time is increased should external forces 3032 result in waveguide 2505 expanding in length. The change in transit time delivers digital pulses 3026 earlier or later than previous pulses thereby producing an adjustment to the delivery of analog pulses 3018 and 3014 to a new equilibrium point. The new equilibrium point will correspond to a different transit time (e.g. different frequency) but the same integer number of pulses.

[00276] Shown in FIG. 31 are pulses 3122, 3124, 3126 and 3128 that are emitted into waveguide 2505 by transducer 2504 after switch 3028 is closed. Transducer 2504 emits pulses 3122, 3124, 3126, and 3128 in response to pulses 31 10, 31 12, 31 14, and 31 16 output by amplifier 3020 that respectively correspond to the detection of propagated pulsed energy waves 3120, 3122, 3124, and 3126 of FIG. 31 that have been reflected back to the first location. Although only four pulsed energy waves are shown in FIG. 31 , they will continue to be emitted into waveguide 2505 for measurement as long as switch 3028 remains closed. The transit time 3154 of pulses 3120, 3122, 3124, 3126, and 3128 correspond to the parameter being measured (e.g. force or pressure in the example). Switch 3004 closes and switch 3028 opens after pulse 31 16 thereby breaking the positive closed loop feedback. This is indicated by open 3140 for switch 3028 after pulse 31 16. Switch 3004 is enable as indicated by closed 3142 but no pulses are output by pulse circuit 3008. Transducer 2504 does not emit any pulsed energy waves until pulse circuit 3008 initiates another measurement sequence.

[00277] In one embodiment, transit time 3030 of each pulse can be measured by digital logic circuit 3075 using a high-speed clock and a counter. For example, an edge of analog pulse 3014 provided to transducer 2504 can initiate a count by the high-speed clock. The generation of a digital pulse 3026 can stop the count and store the number in memory. The count is multiplied by the time period of a clock cycle, which will correspond to the transit time of the pulsed energy wave. The clock can be reset for the next measurement sequence in response to the digital pulse 3024. A similar approach can be deployed measuring a time period of a pulse to pulse output by amplifier 3020.

[00278] As previously disclosed, the repetition rate of energy waves 3016 during operation of the closed loop circuit, and changes in this repetition rate, can be used to measure changes in the movement or changes in the physical attributes of energy propagating structure or medium 2505. The changes can be imposed on the energy propagating structure or medium 2505 by external forces or conditions 3032 thus translating the levels and changes of the parameter or parameters of interest into signals that may be digitized for subsequent processing, storage, and display. Thus, the repetition rate of pulses of energy waves 3016 can be related to a pulsed energy wave time period of single pulsed energy wave or over multiple pulsed energy wave time periods during the operation of the closed loop circuit, and changes in this repetition rate, can be used to measure movement or changes in physical attributes of energy propagating structure, medium, or waveguide 2505.

[00279] The changes in physical attributes of energy propagating structure or waveguide 2505 by external forces or conditions 3032 translates the levels and modifies the parameter or parameters of interest into a time period difference of adjacent pulses, a time period difference of transit time, or a difference accumulated or averaged over multiple time periods for the pulsed energy wave time period or transit time. The time period or transit time corresponds to a frequency for the time period measured. The new frequency can be digitized for subsequent transmission, processing, storage, and display. Translation of the measured frequency into digital binary numbers facilitates communication, additional processing, storage, and display of information about the level and changes in physical parameters of interest. Prior to measurement of the frequency, control circuit 3006 loads the loop count into digital timer 3034 that is stored in data register 3036. [00280] Digital logic circuit 3075 is described in more detail hereinbelow. As previously mentioned, a first pulse at output 3010 from pulse circuit 3008 initiates a parameter measurement or sensing of waveguide 2505. In at least one exemplary embodiment, sensing does not occur until initial equilibrium has been established. Alternatively, each time period of a pulsed energy wave or transit time period 3030 of the pulsed energy wave can be measured and reviewed. Thus, each pulse energy wave detection and generation of a digital pulse can be a separate and unique event. Control circuit 3006 detects digital pulses 3026 from amplifier 3020 (closing switch 3028 and opening switch 3004) to establish equilibrium and start measurement operations. In an extended configuration of pulse echo mode, a digital block is coupled to the pulsed echo mode measurement system for digitizing the frequency of operation. Translation of the time period of pulsed energy waves into frequency (digital binary numbers) facilitates communication, additional processing, storage, and display of information about the level and changes in physical parameters of interest. During this process, control circuit 3006 enables digital counter 3038 and digital timer 3034. Digital counter 3038 decrements its value on the rising edge of each digital pulse output by amplifier 3020. In one embodiment, digital timer 3034 increments its value on each rising edge of pulses from a clock circuit. A clock such as a crystal oscillator is used to clock digital logic circuit 3075 and as a reference in which to gauge time periods of pulsed energy waves. Alternatively, pulse circuit 3008 can be a reference clock. When the number of digital pulses 3026 has decremented, the value within digital counter 3038 to zero a stop signal is output from digital counter 3038. The stop signal disables digital timer 3034 and triggers control circuit 3006 to output a load command to data register3036. Data register 3036 loads a binary number from digital timer 3034 that is equal to the period of the energy waves or pulses times the value in counter 3038 divided by a clock period corresponding to oscillator output 3010. With a constant clock period, the value in data register 3036 is directly proportional to the aggregate period of the pulsed energy waves or pulses accumulated during the measurement operation. Duration of the measurement operation and the resolution of measurements may be adjusted by increasing or decreasing the value preset in the count register 3040. [00281] This method of operation further enables setting the level of precision or resolution of the captured data by using long cycle counts to optimize trade-offs between measurement resolution versus pulse repetition rate, ultrasound frequency, and damping waveform shape, as well as the bandwidth of the sensing and the speed of the data processing operations to achieve an optimal operating point for a sensing module or device that matches the operating conditions of the system containing, or subject to, the parameter or parameters of interest.

[00282] In at least one exemplary embodiment, the sensor system includes the system as a wireless module that operates according to one or more criteria such as, but not limited to, power level, applied force level, standby mode, application context, temperature, or other parameter level. Pulse shaping can also be applied to increase reception quality depending on the operational criteria. The wireless sensing module comprises the pulsed measurement system, one or more sensing assemblies, one or more load surfaces, an accelerometer, electronic circuitry, a transceiver, and an energy supply. The wireless sensing module measures a parameter such as force/pressure and transmits the measurement data to a secondary system for further processing and display. The electronic circuitry in conjunction with the sensing assemblies accurately measures physical displacements of the load surfaces on the order of a few microns more or less along various physical dimensions. The sensing assembly physically changes in response to an applied force, such as an applied load. Electronic circuitry operating in a positive feedback closed-loop circuit configuration precisely measures changes in propagation time due to changes in the length of the waveguides; physical length changes which occur in direct proportion to the applied force.

[00283] In a non-limiting example, an ultrasound signal is used in the measurement system. For illustration purposes, the measurement system measures a load, pressure, or force. The system has two surfaces to which the measured parameter (e.g. load, pressure, force) can be applied. In one embodiment, one of the surfaces is in a fixed position and the measured parameter is applied to the remaining surface. Alternatively, the measured parameter can be applied across both surfaces. In one embodiment, the system will measure within a range of 3-60 pounds.

[00284] The sensing element comprises a piezoelectric transducer, a medium, and a reflective surface. One or more sensing elements can be used. The sensing element is placed between the surfaces of the measurement system. In one embodiment, the waveguide comprises a polymer such as urethane or polyethylene. In a non-limiting example, the polymer can be stretched or compressed when subjected to the parameter under measurement and the system has little or no hysteresis. The waveguide efficiently contains and directs an ultrasonic pulsed energy wave such that a measurement of either the transit time of the pulsed energy wave to propagate through the waveguide or time period of the pulsed energy wave can be taken. The waveguide can be cylindrically shaped having a first end and a second end of the cylinder. The piezoelectric transducers are attached at the first and second ends of the waveguide to emit and receive ultrasonic pulsed energy waves. The transducers are attached to be acoustically coupled the waveguide and can have an intermediate material layer to aid in improving the transfer of the ultrasonic pulsed energy wave.

[00285] In the non-limiting example, the waveguide in a relaxed state is a cylinder or column 47 millimeters long, which accommodates one, or more ultrasonic pulsed energy waves. The length of the waveguide corresponds to the thickness of the sensor and is thus an indication that a very small form factor sensor can be built using this methodology. In one embodiment, the waveguide is placed in a compressed state in the sensor module. In the non- limiting example, the waveguide is subjected to a force or pressure that changes the dimensions of the cylinder. More specifically, an applied force or pressure on the surfaces of the system modifies the length of the waveguide. In one embodiment, the waveguide is compressed from the 47 millimeter relaxed state to a thickness of approximately 39 millimeters. The 39 millimeter compressed state corresponds to the state where no load is applied to the surfaces of the sensor module. [00286] In the non-limiting example, the emitting piezoelectric transducer has a different resonant frequency than the receiving piezoelectric transducer. The emitting piezoelectric transducer has a resonance frequency of approximately 8 megahertz. It has a diameter of approximately 3.3 millimeters and is approximately 0.23 millimeters thick. The receiving piezoelectric transducer has a resonance frequency of approximately 10-13 megahertz. It has a diameter of 4 millimeters and is approximately 0.17 millimeters. In one embodiment, the waveguide has a diameter greater than or equal to the diameter of the largest piezoelectric transducer. In the example, the waveguide would have a diameter greater than or equal to 4 millimeters.

[00287] The sensing module can very accurately measure transit time or a time period of the pulsed energy wave as disclosed hereinabove. In at least one exemplary embodiment, a single pulsed energy wave can be used to take a measurement thereby minimizing energy usage. Alternatively, more than one measurement can be taken sequentially, periodically, or randomly depending on the application requirements. The measured transit time or time period corresponds to the length of the medium or waveguide. The transit time or time period is correlated to a force or pressure required to compress the waveguide by the measured amount. Preliminary measurements indicate that the sensing module can detect changes in the length of the waveguide on the order of submicrons. Thus, the sensing module can measure the force or changes in force with high precision.

[00288] Upon reviewing the aforementioned embodiments, it would be evident to an artisan with ordinary skill in the art that said embodiments could be modified, reduced, or enhanced without departing from the scope and spirit of the claims described below. As an example:

[00289] Changing repetition rate of complex waveforms to measure time delays.

[00290] Changing repetition rate of acoustical, sonic, or light, ultraviolet, infrared, RF or other electromagnetic waves, pulses, or echoes of pulses to measure changes in the parameter or parameters of interest. [00291] FIG. 32 is an exemplary block diagram of the components of a sensing module. It should be noted that the sensing module could comprise more or less than the number of components shown. As illustrated, the sensing module includes one or more sensing assemblages 3203, a transceiver 3220, an energy storage 3230, electronic circuitry 3207, one or more mechanical supports 3215 (e.g., springs), and an accelerometer 3202. In the non-limiting example, an applied compressive force can be measured by the sensing module.

[00292] The sensing assemblage 3203 can be positioned, engaged, attached, or affixed to the contact surfaces 3206. Mechanical supports 3215 serve to provide proper balancing of contact surfaces 3206. In at least one exemplary embodiment, contact surfaces 3206 are load-bearing surfaces. In general, the propagation structure 3205 is subject to the parameter being measured. Surfaces 3206 can move and tilt with changes in applied load; actions which can be transferred to the sensing assemblages 3203 and measured by the electronic circuitry 3207. The electronic circuitry 3207 measures physical changes in the sensing assemblage 3203 to determine parameters of interest, for example a level, distribution and direction of forces acting on the contact surfaces 3206. In general, the sensing module is powered by the energy storage 3230.

[00293] As one example, the sensing assemblage 3203 can comprise an elastic or compressible propagation structure 3205 between a transducer 3204 and a reflective surface 3214. In the current example, transducer 3204 can be an ultrasound (or ultrasonic) resonator, and the elastic or compressible propagation structure 3205 can be an ultrasound (or ultrasonic) waveguide (or waveguides). The electronic circuitry 3207 is electrically coupled to the sensing assemblages 3203 and translates changes in the length (or compression or extension) of the sensing assemblages 3203 to parameters of interest, such as force. It measures a change in the length of the propagation structure 3205 (e.g., waveguide) responsive to an applied force and converts this change into electrical signals which can be transmitted via the transceiver 3220 to convey a level and a direction of the applied force. In other arrangements herein contemplated, the sensing assemblage 3203 may require only a single transducer. In yet other arrangements, the sensing assemblage 3203 can include piezoelectric, capacitive, optical or temperature sensors or transducers to measure the compression or displacement. It is not limited to ultrasonic transducers and waveguides.

[00294] The accelerometer 3202 can measure acceleration and static gravitational pull. It can include single-axis and multi-axis structures to detect magnitude and direction of the acceleration as a vector quantity, and can be used to sense orientation, vibration, impact and shock. The electronic circuitry 3207 in conjunction with the accelerometer 3202 and sensing assemblies 3203 can measure parameters of interest (e.g., distributions of load, force, pressure, displacement, movement, rotation, torque and acceleration) relative to orientations of the sensing module with respect to a reference point. In such an arrangement, spatial distributions of the measured parameters relative to a chosen frame of reference can be computed and presented for real-time display.

[00295] The transceiver 3220 comprises a transmitter 3209 and an antenna 3210 to permit wireless operation and telemetry functions. Once initiated the transceiver 3220 can broadcast the parameters of interest in real-time. The telemetry data can be received and decoded with various receivers, or with a custom receiver. The wireless operation can eliminate distortion of, or limitations on, measurements caused by the potential for physical interference by, or limitations imposed by, wiring and cables connecting the sensing module with a power source or with associated data collection, storage, display equipment, and data processing equipment.

[00296] The transceiver 3220 receives power from the energy storage 3230 and can operate at low power over various radio frequencies by way of efficient power management schemes, for example, incorporated within the electronic circuitry 3207. As one example, the transceiver 3220 can transmit data at selected frequencies in a chosen mode of emission by way of the antenna 3210. The selected frequencies can include, but are not limited to, ISM bands recognized in International Telecommunication Union regions 1 , 2 and 3. A chosen mode of emission can be, but is not limited to, Gaussian Frequency Shift Keying, (GFSK), Amplitude Shift Keying (ASK), Phase Shift Keying (PSK), Minimum Shift Keying (MSK), Frequency Modulation (FM), Amplitude Modulation (AM), or other versions of frequency or amplitude modulation (e.g., binary, coherent, quadrature, etc.).

[00297] The antenna 3210 can be integrated with components of the sensing module to provide the radio frequency transmission. The substrate for the antenna 3210 and electrical connections with the electronic circuitry 3207 can further include a matching network. This level of integration of the antenna and electronics enables reductions in the size and cost of wireless equipment. Potential applications may include, but are not limited to any type of short- range handheld, wearable, or other portable communication equipment where compact antennas are commonly used. This includes disposable modules or devices as well as reusable modules or devices and modules or devices for long-term use.

[00298] The energy storage 3230 provides power to electronic components of the sensing module. It can be charged by wired energy transfer, short- distance wireless energy transfer or a combination thereof. External power sources can include, but are not limited to, a battery or batteries, an alternating current power supply, a radio frequency receiver, an electromagnetic induction coil, a photoelectric cell or cells, a thermocouple or thermocouples, or an ultrasound transducer or transducers. By way of the energy storage 3230, the sensing module can be operated with a single charge until the internal energy is drained. It can be recharged periodically to enable continuous operation. The energy storage 3230 can utilize common power management technologies such as replaceable batteries, supply regulation technologies, and charging system technologies for supplying energy to the components of the sensing module to facilitate wireless applications.

[00299] The energy storage 3230 minimizes additional sources of energy radiation required to power the sensing module during measurement operations. In one embodiment, as illustrated, the energy storage 3230 can include a capacitive energy storage device 3208 and an induction coil 321 1. External source of charging power can be coupled wirelessly to the capacitive energy storage device 3208 through the electromagnetic induction coil or coils 321 1 by way of inductive charging. The charging operation can be controlled by power management systems designed into, or with, the electronic circuitry 3207. As one example, during operation of electronic circuitry 3207, power can be transferred from capacitive energy storage device 3208 by way of efficient step-up and step-down voltage conversion circuitry. This conserves operating power of circuit blocks at a minimum voltage level to support the required level of performance.

[00300] In one configuration, the energy storage 3230 can further serve to communicate downlink data to the transceiver 3220 during a recharging operation. For instance, downlink control data can be modulated onto the energy source signal and thereafter demodulated from the induction coil 321 1 by way of electronic control circuitry 3207. This can serve as a more efficient way for receiving downlink data instead of configuring the transceiver 3220 for both uplink and downlink operation. As one example, downlink data can include updated control parameters that the sensing module uses when making a measurement, such as external positional information, or for recalibration purposes, such as spring biasing. It can also be used to download a serial number or other identification data.

[00301] The electronic circuitry 3207 manages and controls various operations of the components of the sensing module, such as sensing, power management, telemetry, and acceleration sensing. It can include analog circuits, digital circuits, integrated circuits, discrete components, or any combination thereof. In one arrangement, it can be partitioned among integrated circuits and discrete components to minimize power consumption without compromising performance. Partitioning functions between digital and analog circuit enhances design flexibility and facilitates minimizing power consumption without sacrificing functionality or performance. Accordingly, the electronic circuitry 3207 can comprise one or more Application Specific Integrated Circuit (ASIC) chips, for example, specific to a core signal processing algorithm. [00302] In another arrangement, the electronic circuitry can comprise a controller such as a programmable processor, a Digital Signal Processor (DSP), a microcontroller, or a microprocessor, with associated storage memory and logic. The controller can utilize computing technologies with associated storage memory such a Flash, ROM, RAM, SRAM, DRAM or other like technologies for controlling operations of the aforementioned components of the sensing module. In one arrangement, the storage memory may store one or more sets of instructions (e.g., software) embodying any one or more of the methodologies or functions described herein. The instructions may also reside, completely or at least partially, within other memory, and/or a processor during execution thereof by another processor or computer system.

[00303] FIG. 33 is an exemplary block diagram of a positive feedback closed-loop measurement system 3300 in pulse mode in accordance with one embodiment. The measurement system corresponds to components of the sensing module 2501 shown in FIG. 25. The measurement system includes a sensing assemblage 2902 and a pulsed system 2904 that detects energy waves 3306 in one or more waveguides 2505 of the sensing assembly 2902. A pulse 2920 is generated in response to the detection of energy waves 3306 to initiate a propagation of a new pulse in waveguide 2505.

[00304] In this embodiment, the sensing assembly 2902 comprises transducer 2504, transducer 3330, and a waveguide 2505 (or energy propagating structure). In a non-limiting example, sensing assemblage 2902 is affixed to load bearing or contacting surfaces. External forces 2908 applied to the contacting surfaces compress the waveguide 2505 and change the length of the waveguide 2505. The transducers 2504 and 3330 will also be moved closer together. The change in distance affects the transit time 3310 of energy waves 3306 transmitted and received between transducers 2504 and 3330. The pulsed system 2904 in response to these physical changes will detect each energy wave sooner (e.g. shorter transit time) and initiate the propagation of new pulses associated with the shorter transit time. As will be explained below, this is accomplished by way of pulse system 2904 in conjunction with the pulse circuit 2912, the mode control 2914, and the edge detect circuit 2916.

[00305] Notably, changes in the waveguide 2505 (energy propagating structure or structures) alter the propagation properties of the medium of propagation (e.g. transit time 3310). A pulsed approach reduces power dissipation allowing for a temporary power source such as a battery or capacitor to power the system during the course of operation. In at least one exemplary embodiment, a pulse is provided to transducer 2504 coupled to a first surface of waveguide 2505. Transducer 2504 generates a pulsed energy wave 3306 coupled into waveguide 2505. In a non-limiting example, transducer 2504 is a piezo-electric device capable of transmitting and receiving acoustic signals in the ultrasonic frequency range.

[00306] Transducer 3330 is coupled to a second surface of waveguide 2505 to receive the propagated pulsed signal and generates a corresponding electrical signal. The electrical signal output by transducer 3330 is coupled to edge detect circuit 2916. In at least one exemplary embodiment, edge detect circuit 2916 detects a leading edge of the electrical signal output by transducer 3330 (e.g. the propagated energy wave 3306 through waveguide 2505). The detection of the propagated pulsed signal occurs earlier (due to the length/distance reduction of waveguide 2505) than a signal prior to external forces 2908 being applied to sensing assemblage 2902. Pulse circuit 2912 generates a new pulse in response to detection of the propagated pulsed signal by edge detect circuit 2916. The new pulse is provided to transducer 2504 to initiate a new pulsed sequence. Thus, each pulsed sequence is an individual event of pulse propagation, pulse detection and subsequent pulse generation that initiates the next pulse sequence.

[00307] The transit time 3310 of the propagated pulse corresponds to the time from the detection of one propagated pulse to the next propagated pulse. There is delay associated with each circuit described above. Typically, the total delay of the circuitry is significantly less than the propagation time of a pulsed signal through waveguide 2505. In at least one exemplary embodiment, the variation in circuit delay under equilibrium conditions variations is relatively small or insignificant in comparison to the measurement. Multiple pulse to pulse timings can be used to generate an average time period when change in external forces 2908 occur relatively slowly in relation to the pulsed signal propagation time such as in a physiologic or mechanical system. The digital counter 2918 in conjunction with electronic components counts the number of propagated pulses to determine a corresponding change in the length of the waveguide 2505. These changes in length change in direct proportion to the external force thus enabling the conversion of changes in parameter or parameters of interest into electrical signals.

[00308] In at least one exemplary embodiment, pulsed system 2904 in conjunction with one or more sensing assemblages 2902 are used to take measurements on a muscular-skeletal system. In a non-limiting example, sensing assemblage 2902 is placed between a femoral prosthetic component and tibial prosthetic component to provide measured load information that aids in the installation of an artificial knee joint. The measurements can be made in extension and in flexion. Assemblage 2902 is used to measure the condyle loading to determine if it falls within a predetermined range and location. Based on the measurement, the surgeon can select the thickness of the insert such that the measured loading and incidence with the final insert in place will fall within the predetermined range. Soft tissue tensioning can be used by a surgeon to further optimize the force or pressure. Similarly, two assemblages 2902 can be used to measure both condyles simultaneously or multiplexed. The difference in loading (e.g. balance) between condyles can be measured. Soft tissue tensioning can be used to reduce the force on the condyle having the higher measured loading to reduce the measured pressure difference between condyles.

[00309] One method of operation holds the number of pulsed energy waves propagating through waveguide 2505 as a constant integer number. A time period of a pulsed energy wave corresponds to the time between the leading pulse edges of adjacent pulsed energy waves. A stable time period is one in which the time period changes very little over a number of pulsed energy waves. This occurs when conditions that affect sensing assemblage 2902 stay consistent or constant. Holding the number of pulsed energy waves propagating through waveguide 2505 to an integer number is a constraint that forces a change in the time between pulses when the length of waveguide 2505 changes. The resulting change in time period of each pulsed energy wave corresponds to a change in aggregate pulse periods that is captured using digital counter 2918 as a measurement of changes in external forces 2908 or conditions.

[00310] A further method of operation according to one embodiment is described hereinbelow for pulsed energy wave 3306 propagating from transducer 2504 and received by transducer 3330. In at least one exemplary embodiment, pulsed energy wave 3306 is an ultrasonic energy wave. Transducers 2504 and 3330 are piezo-electric resonator transducers. Although not described, wave propagation can occur in the opposite direction being initiated by transducer 3330 and received by transducer 2504. Furthermore, detecting ultrasound resonator transducer 3330 can be a separate ultrasound resonator as shown or transducer 2504 can be used solely depending on the selected mode of propagation (e.g. reflective sensing). Changes in external forces or conditions 2908 affect the propagation characteristics of waveguide 2505 and alter transit time 3310. As mentioned previously, pulsed system 2904 holds constant an integer number of pulsed energy waves 3306 propagating through waveguide 2505 (e.g. an integer number of pulsed energy wave time periods) thereby controlling the repetition rate. As noted above, once pulsed system 2904 stabilizes, the digital counter 2918 digitizes the repetition rate of pulsed energy waves, for example, by way of edge-detection, as will be explained hereinbelow in more detail.

[00311] In an alternate embodiment, the repetition rate of pulsed energy waves 3306 emitted by transducer 2504 can be controlled by pulse circuit 2912. The operation remains similar where the parameter to be measured corresponds to the measurement of the transit time 3310 of pulsed energy waves 3306 within waveguide 2505. It should be noted that an individual ultrasonic pulse can comprise one or more energy waves with a damping wave shape as shown. The pulsed energy wave shape is determined by the electrical and mechanical parameters of pulse circuit 2912, interface material or materials, where required, and ultrasound resonator or transducer 2504. The frequency of the energy waves within individual pulses is determined by the response of the emitting ultrasound resonator 2504 to excitation by an electrical 2520. The mode of the propagation of the pulsed energy waves 3306 through waveguide 2505 is controlled by mode control circuitry 2914 (e.g., reflectance or uni-directional). The detecting ultrasound resonator or transducer may either be a separate ultrasound resonator or transducer 3330 or the emitting resonator or transducer 2504 depending on the selected mode of propagation (reflectance or unidirectional).

[00312] In general, accurate measurement of physical parameters is achieved at an equilibrium point having the property that an integer number of pulses are propagating through the energy propagating structure at any point in time. Measurement of changes in the "time-of-flight" or transit time of ultrasound pulses within a waveguide of known length can be achieved by modulating the repetition rate of the ultrasound pulses as a function of changes in distance or velocity through the medium of propagation, or a combination of changes in distance and velocity, caused by changes in the parameter or parameters of interest.

[00313] It should be noted that ultrasound energy pulses or waves, the emission of ultrasound pulses or waves by ultrasound resonators or transducers, transmitted through ultrasound waveguides, and detected by ultrasound resonators or transducers are used merely as examples of energy pulses, waves, and propagation structures and media. Other embodiments herein contemplated can utilize other wave forms, such as, light.

[00314] Measurement by pulsed system 2904 and sensing assemblage 2902 enables high sensitivity and signal-to-noise ratio as the time-based measurements are largely insensitive to most sources of error that may influence voltage or current driven sensing methods and devices. The resulting changes in the transit time of operation correspond to frequency which can be measured rapidly and with high resolution. This achieves the required measurement accuracy and precision thus capturing changes in the physical parameters of interest and enabling analysis of their dynamic and static behavior.

[00315] In summary, the invention describes a system to define the joint gap, bone preparation, alignment, load, and balance by measurement. Furthermore the surgeon obtains the information in real time from the system while soft tissue release and alignment is being performed. The graphic user interface can be in the device itself or integrated with a processing unit and display in the operating room. The sensors can be incorporated into tools and equipment for measuring the muscular-skeletal system pre-operatively, intra- operatively, post-operatively, and long term. The sensors or sensor system is in communication with a data registry and repository to generate statistically significant data that can be used as clinical evidence. The data repository and registry further includes information used in evidentiary based orthopedic medicine. This invention while intended for use in the medical field and more specifically orthopedics uses a knee application to illustrate principles of the system and method for illustrative purposes only and can be similarly adapted for the hip, shoulder, ankle, spine, as well as to measure other parameters of a biological system.

[00316] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

CLAIMSWhat is claimed is:

1. A distractor system comprising: a first support structure having a superior surface; a second support structure having an inferior surface; a lift mechanism coupled to the first and second support structures to adjustably separate the first support structure from the second support structure; and a sensor overlying one of the superior surface or the inferior surface to measure a parameter of the muscular-skeletal system.

2. The system of claim 1 further including: a first cavity in the superior surface of the first support structure; a second cavity in the superior surface of the first support structure; a first sensor fitted in the first cavity having a surface for receiving a medial condyle; and a second sensor fitted in the second cavity having a surface for receiving a lateral condyle.

3. The system of claim 1 further including a handle operatively coupled to the lift mechanism.

4. The system of claim 1 further including a rod operatively coupled to the handle.

5. The system of claim 4 where the rod is used to align one or more bones of the muscular skeletal system.

6. The system of claim 4 further including a cutting block coupled to the rod.

7. The system of claim 1 where the lift mechanism comprises: a scissor mechanism coupled to an interior surface of the first and second support structures; and a threaded shaft operatively coupled to the scissor mechanism where rotation of the threaded shaft raises and lowers the scissor mechanism thereby increasing or decreasing a gap between the first and second support structures.

8. The system of claim 1 further including a handle operatively coupled to the lift mechanism where at least one laser pointer is coupled to the handle and directed to at least one target to aid in alignment.

9. The system of claim 1 further including a processing unit; a communication circuit coupled to the processing unit; and a display operatively coupled to the processor for displaying information received wired or wirelessly from the sensor.

10. The system of claim 1 where the sensor measures one of force, pressure, or load.

1 1. A method of distracting a muscular-skeletal system comprising the steps of: placing a sensor in the dynamic distractor; inserting a dynamic distractor between a first surface and a second surface of the muscular-skeletal system; expanding the dynamic distractor to create a gap of a predetermined height; measuring a parameter of the muscular-skeletal system at the predetermined height; and removing the sensor from the dynamic distractor.

12. The method of claim 1 1 where the step of expanding the dynamic distractor further includes the steps of: expanding the dynamic distractor until the loading is within a predetermined range; measuring the distance from the superior surface to the inferior surface of the dynamic distractor when the loading on the dynamic distractor is within the predetermined range; and selecting an insert thickness.

13. The method of claim 1 1 further including the steps of: transmitting measurement data from the sensor to a processing unit; adjusting the loading applied by the first and second surfaces of the muscular-skeletal system using soft tissue release with the dynamic distractor in place.

14. The method of claim 1 1 further including the steps of: measuring loading on at least two regions of the first or second surfaces of the muscular-skeletal system; and adjusting the differential loading using soft tissue release to modify a balance between the at least two regions with the dynamic distractor in place.

15. The method of claim 1 1 further including the steps of: generating relational positioning information using one or more accelerometers; transmitting the relational positioning information to a processing unit; emitting a signal from the dynamic distractor to a first target; emitting a signal from the dynamic distractor to a second target where a position of the first target, the dynamic distractor, and the second target correspond to a mechanical axis of the muscular-skeletal system; and measuring misalignment of the first and second surfaces to the mechanical axis.

16. A distractor system comprising: a first support structure having a superior surface; a second support structure having an inferior surface; a lift mechanism coupled to the first and second support structures to adjustably separate the first support structure from the second support structure; at least one cavity in either the superior or inferior surfaces; and a sensor in the at least one cavity to measure a parameter coupled thereto.

17. The system of claim 16 further including: a handle coupled to the lift mechanism; and a cutting block; an uprod coupled between the handle and the cutting block to align and stabilize the cutting block along a mechanical axis.

18. The system of claim 16 where the cutting block and uprod are removed from the distractor system and where a rod is coupled to the handle to aid in alignment verification.

19. The system of claim 16 further including a handle operatively coupled to the lift mechanism where at least one laser pointer is coupled to the handle and directed to at least one target to aid in alignment.

20. The system of claim 16 further including a processing unit; a communication circuit coupled to the processing unit; and a display operatively coupled to the processor for displaying information received wired or wirelessly from the sensor.

21. The system of claim 16 where the lift mechanism comprises: a scissor mechanism coupled to an interior surface of the first and second support structures; and a threaded shaft operatively coupled to the scissor mechanism where rotation of the threaded shaft raises and lowers the scissor mechanism thereby increasing or decreasing a gap between the first and second support structures.