WO1998051240A1

WO1998051240A1 - Temporary implantable prosthesis

Info

Publication number: WO1998051240A1
Application number: PCT/US1998/009514
Authority: WO
Inventors: C. Lowry Barners; Michael G. Guidera
Original assignee: Hayes Medical, Inc.
Priority date: 1997-05-15
Filing date: 1998-05-12
Publication date: 1998-11-19
Also published as: AU7295398A

Abstract

A temporary implanting prosthesis (110, 120, 130) is provided. A temporary implanting prosthesis (110, 120, 130) is used to temporarily replace a permanent prosthesis (200) when, e.g., an infection develops in proximity to the site of the permanent prosthesis (200). A temporary implanting prosthesis (110, 120, 130) has a mantle portion (120), and an implant portion (110) wherein the mantle portion (120), and implant portion (110) are sized and shaped so that the temporary implanting prosthesis (110, 120, 130) can replace any permanent prosthesis (200) in a set of permanent prostheses that have a similar size, and shape to the temporary implanting prosthesis (110, 120, 130). A preferred temporary implanting prosthesis (110, 120, 130) is made using a standardized mantle (120), a standardized implant (110) where each of these components is designed to replace mantle portions (210), and implant portions (220) of a set of permanent prostheses (200).

Description

TEMPORARY IMPLANTABLE PROSTHESIS

BACKGROUND AND SUMMARY OF THE INVENTION

Field of the invention

The invention provides a temporary implantable prosthesis which is used, for example, to replace a permanent prosthesis which has been removed from a patient's femur and acetabulum or humerus in order to treat a deep infection of a patient's joint.

Problems addressed by the invention

There are many opportunities for an infection of the joint and surrounding bone to develop when a patient has a prosthesis implanted in e.g. the patient's hip. An infection can develop many years after a prosthesis has been implanted within the patient. Bacteria from another infection (such as a tooth or urinary tract infection) enters the blood-stream and infects the site where the prosthesis was implanted. An infection can also develop as a result of surgery to implant the prosthesis within the patient. Although surgeons and hospitals take extensive precautionary measures to prevent an infection from occurring, there are many instances where an infection develops in the patient's bone in the vicinity of the prosthesis. Hip replacement surgery requires the surgeon to physically access the patient's femur. A significant amount of the tissue above the femur is cut and laid back to gain access to the femur. The surgeon removes the head from the femur, exposing the intramedullary canal. The surgeon subsequently broaches and/or mills the femur by inserting equipment into the canal. The surgeon then inserts the long stem and tapering body of the prosthesis into the enlarged intramedullary canal within the femur to anchor the prosthesis. Oftentimes the prosthesis does not seat properly and must be at least partially removed from the patient and reseated in the femur. An infectious agent can enter the area surrounding the joint during any of these steps.

A patient who contracts an infection after a prosthesis is implanted must return to the hospital and have the prosthesis removed. The patient is treated with antibiotics orally or intravenously until the infectious agent is killed, which takes approximately eight weeks or more. The patient then returns to the hospital and has another prosthesis implanted.

It is very difficult for the patient to walk or move about during the period that the patient's prosthesis is removed. Since a portion of the femur is missing, the patient's leg from which the prosthesis was removed is useless.

The patient's leg cannot support the patient or otherwise be used to help the patient move. The patient must use crutches or a walker for limited movements and, if the patient is bedridden, the patient can contract other diseases such as pneumonia during the months that the patient is confined to bed.

Further, it can take a significant period of time for oral or intravenous administration of the antibiotic to kill the infectious agent in the patient's bone and joint. Much of the antibiotic is filtered from the patient's blood or otherwise removed before the antibiotic encounters the infectious agent. It would be very desirable to be able to administer an antibiotic locally to kill the infection.

Solution to the problems

The invention provides a temporary implantable prosthesis and an associated set of components used to construct a temporary implantable prosthesis. In a preferred embodiment of the invention, the temporary implantable prosthesis holds an antibiotic that is administered locally to kill an infection within the patient's bone.

A temporary implantable prosthesis substitutes for a permanent prosthesis when it is necessary to remove the permanent prosthesis from a patient and, e.g., treat an infection of the patient's joint. A temporary implantable prosthesis has a mantle portion and an implant portion which are each sized and shaped such that the temporary implantable prosthesis can be used to replace any of a number of differently-sized and/or shaped permanent prostheses selected from a set of corresponding permanent prostheses. Thus, a temporary implantable prosthesis can be used to replace a permanent prosthesis to be removed from a first patient, or the same temporary implantable prosthesis can be used to replace at least one other, differently- shaped and/or sized permanent prosthesis in a different patient.

In a preferred embodiment of the invention, a temporary implantable prosthesis comprises two parts, a standardized mantle and an implant. The standardized mantle is shaped to be placed within the cavity in the bone from which the permanent prosthesis was removed. The implant is a portion of the temporary implantable prosthesis which is embedded into or otherwise formed as part of the mantle, and which connects to the acetabulum or scapula to allow loads to pass from e.g. the pelvis and into the femur.,

The invention also provides a set of components for making temporary implantable prostheses. The components include standardized molds for casting the mantle, standardized implants, standardized broaches, a construction stand that holds a mold and implant to form a temporary implantable prosthesis, and standardized templates that correspond to the sizes and shapes of the mantles and the implants. A set of components can be, e.g., two or more individual components of different types (a standardized mold and a standardized implant, for example), or a set of components can be, e.g., two or more of the same type of component (two or more standardized molds, for example).

Among other factors, the invention is based on the technical finding that a temporary implantable prosthesis comprised of a standardized mantle and a standardized implant is an inexpensive prosthesis which can be used to replace a permanent prosthesis within a patient's shoulder or hip and even to help treat an infection surrounding the joint site while providing the patient with the ability to move about during the period of time that the permanent prosthesis is removed from the patient. The patient is thus less susceptible to other opportunistic diseases such as pneumonia. These technical findings and others are apparent from the discussion herein.

BRIEF DESCRIPTION OF THE FIGURES

The Figures illustrate certain preferred embodiments of the invention, and, consequently, the claims are to be given their broadest interpretation that is consistent with the specification, the drawings, and the meaning of terms used herein to one of ordinary skill in the art.

Figure 1 illustrates one embodiment of a temporary implantable prosthesis, in which a standardized mantle 120 is formed about a standardized implant 110. The standardized implant has a taper 130, on which a standard head (not shown) is placed.

Figures 2A-1 and 2A-2 show a side view and a rear view of a permanent cemented implant. Figure 2B-1 and 2B-2 show a rear and side view of a permanent cementless implant.

Figures 3A and 3B illustrate two templates that correspond to the temporary standardized implant of Figure 1, which templates are placed over X-ray photographs of a patient's bone to assess fit of the temporary standardized implant within the intramedullary canal of the bone.

Figure 4 shows a set of six broaches of different sizes, each of which corresponds to a temporary implantable prosthesis.

Figure 5 illustrates a mold for casting differently-sized and/or shaped standardized mantles about an implant. Figure 6 illustrates a tapered sleeve which fits over a taper on a temporary implantable prosthesis. The tapered sleeve is used to provide different offsets to the head when it is placed over the tapered sleeve.

Figures 7A and 7B show a head for placement over the tapered sleeve or for placement directly onto the taper of the temporary implantable prosthesis. The head has holes that allow antibiotic within cement packed into the hollow head to leach from the cement and to the site of infection.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Temporary Implantable Prosthesis

As discussed above, a temporary implantable prosthesis substitutes for a permanent prosthesis when it is necessary to remove the permanent prosthesis from a patient and, e.g., treat an infection of the patient's surrounding joint space. A temporary implantable prosthesis has a mantle portion and an implant portion wherein each portion is sized and shaped such that the temporary implantable prosthesis can be used to replace any of a number of differently-sized and/or shaped permanent prostheses selected from a set of corresponding permanent prostheses.

The mantle portion fits within the cavity in the patient's femur or humerus from which the permanent prosthesis was removed. The mantle portion is shaped so that little bone has to be removed from the femur or humerus to accommodate the mantle portion, in order to preserve the structural strength and integrity of the patient's femur or humerus.

The implant portion provides the proper length and offset to the temporary implantable prosthesis so that loads from e.g. the pelvis are transmitted through the implant portion and mantle portion and into the femur.

The implant portion either has a head mounting location such as a taper where a unipolar or standard head can be placed, or the implant portion has a head that is formed as part of the implant portion.

Both the mantle portion and the implant portion are also sized and shaped so that a temporary implantable prosthesis as illustrated in Figure 1 can be used to replace any permanent implant selected from a set of corresponding permanent implants. A set of corresponding permanent implants consists of at least two differently-sized and/or shaped permanent implants which are sufficiently similar to one another that a temporary implantable prosthesis can be designed to substitute for each of the permanent implants of the set. Figures 2A-1 and 2A-2 and Figures 2B-1 and 2B-2 illustrate two such permanent prostheses. The permanent implants of the set of corresponding implants have approximately the same length from the bottom of the mantle portion to the free end of the implant portion, approximately the same size and shape of their mantle portions, and approximately the same head offset as their corresponding temporary implantable prosthesis. A surgeon can use a temporary implantable prosthesis of a particular design to replace differently- sized and/or shaped permanent implants in different patients.

A temporary implantable prosthesis and its mantle portion and implant portion can be designed using a number of methods. For example, dimensions and shapes of permanent prostheses are measured, and the permanent prostheses are separated into different sets according to how similar their shapes and overall dimensions are. The mantle portion and implant portion of the temporary implantable prosthesis are then designed so that one temporary implantable prosthesis can be used to replace each member of a set of corresponding permanent prostheses. Or, the designer may choose to place a limitation on the amount of bone that can be removed from a cavity based on the thickness of bone in the area, and the designer can follow the procedure of separating permanent prostheses and determining a best fit as discussed above when designing the temporary implantable prosthesis.

A temporary implantable prosthesis and its mantle portion and implant portion can also be designed by examining X-rays of patients' femurs or humeri to determine dimensions and shapes of cavities and bone locations in patients who have received permanent implants, and then classifying the cavities into sets based on their similarity. The designer designs the mantle portion and the implant portion to provide the best fit based on such criteria as amount of bone removal required, amount of variation in length, width, depth, and shape that is acceptable, and like criteria. Or, a temporary implantable prosthesis can be designed by determining the dimensions and shapes of mantle portions and implant portions of sets of permanent implants and providing components that are sufficiently close in dimension and shape to the mantle portions and implant portions that a temporary implantable prosthesis constructed from the components will substitute for any member of a set of permanent implants.

A temporary implantable prosthesis may be one solid component or separate components that fit together to form a temporary implantable prosthesis. In one preferred embodiment of the invention, a temporary implantable prosthesis comprises two components, a standardized mantle and an implant. A standardized mantle has a size and shape such that the standardized mantle can be used in place of the mantle or body and stem portion of a permanent prosthesis to be removed from a patient. Further, the standardized mantle has a size and shape that is sufficiently similar to the size and shape of mantle portions of a number of different prostheses that the standardized mantle can be used in patients from which any of the permanent prostheses of the set have been removed. Figures 2A-1 and 2A-2 and Figures 2B-1 and 2B-2 illustrate two permanent prostheses and their mantle portions. Figures 2A-1 and 2A-2 show a permanent cemented implant 200 having mantle portion 210 and implant 220, and Figure 2B shows a permanent cementless implant having mantle portion 260. The mantle portions of those prostheses are the portions which are inserted into the cavity broached or milled in the patient's femur or humerus and which transmit much of the load carried by the prosthesis into the surrounding bone.

The standardized mantle may require removal of a small amount of bone to prepare the femoral cavity to accept the standardized mantle, but the standardized mantle does not require removal of so much bone that the bone is substantially weakened to where fracture is likely when the subsequent permanent prosthesis is inserted and used by the patient. Thus, a standardized mantle can be used in place of its corresponding set of prostheses so that a variety of patients can be treated using a single shape. The implant can be a custom or standard implant, for example, which is designed for a particular patient or for use in standard, permanent prostheses. A custom implant may be necessary to obtain a good fit to a particular patient or where a permanent prosthesis must be removed from a patient quickly and the custom implant is the only one available. Preferably the implant is a standardized implant. A standardized implant has a shape and size which allows it to substitute for the portion of the patient's permanent implant above the mantle portion of the implant. Thus, the standardized implant has a size and shape such that the standardized implant cooperates with the standardized mantle to provide a temporary implantable prosthesis that can be used in place of the permanent implant or prosthesis to be removed from a patient, and so that the assembled temporary implantable prosthesis has the necessary strength to allow the patient to move about e.g. on crutches or even on foot. A temporary implantable prosthesis comprising a standardized mantle and a standardized implant can be used to replace a number of custom or standard designs of permanent prostheses when patients develop an infection in the vicinity of their permanent prostheses.

A temporary implantable prosthesis is placed in a patient temporarily, until a time that the patient can accept a subsequent permanent implant. Because a temporary implantable prosthesis is used temporarily within a patient, the temporary implantable prosthesis and/or the standardized implant and standardized mantle can each be designed to be simple pieces that require little machining or few steps to assemble. A temporary implantable prosthesis is thus easy to make, easy to insert, and easy to remove from a patient. Because the temporary implantable prosthesis and its components are less complex than an implant used in a custom prosthesis, a temporary implantable prosthesis is an inexpensive assembly.

Method of and Equipment for Making a Temporary Implantable Prosthesis A temporary implantable prosthesis can be made by many methods. A temporary implantable prosthesis or at least one of the components used to form a temporary implantable prosthesis can be machined from solid materials such as metal and/or plastic, or a temporary implantable prosthesis or at least one of the components used to form a temporary implantable prosthesis can be made by casting e.g. a metal or plastic in a mold. Sets of components can be supplied to a surgeon to assemble during surgery, or a set of components and other pieces can be supplied to a surgeon so that the surgeon can construct a temporary implantable prosthesis during or prior to surgery. One set of components and pieces to make a temporary implantable prosthesis includes a mold having six cavities of different sizes and/or shapes for making standardized mantles, a set of six standardized broaches whose shapes correspond to the shapes of the standardized mantles that are made in the standardized molds, a set of six standardized implants, type and trial unipolar heads of various diameters, four tapered sleeves of various sizes to obtain proper head offset, a construction stand that holds a mold and implant to form a temporary implantable prosthesis, and a set of standardized implant/mantle templates that correspond to the sizes and shapes of the implants and the various mantles that can be formed. One method of making a temporary implantable prosthesis for a femur using the set described above and the method of fitting it to a patient are described in the following discussion. It is to be understood that these methods and the equipment used to implement them can be used to fit a temporary implantable prosthesis into a patient's humerus or other areas of the patient's body. Once a physician has diagnosed that a patient's joint is infected in the region of the patient's permanent prosthesis, the patient's femur is X-rayed to determine the dimensions of the cavity that was broached into the patient's femur to accommodate the permanent prosthesis. The X-ray is performed at a standard distance from the top of the patient's femur in order to obtain a standard scale of dimensions on the X-ray photograph of the femur, the permanent prosthesis, the pelvis, and how the femur aligns with the pelvis. The surgeon selects templates of an implant/mantle profile 300 of Figures 3A and 3B from a temporary implantable prosthesis kit. Two templates as illustrated in Figures 3A and 3B correspond to one temporary implantable prosthesis that is made using the kit. One template 3 10 provides an anterior-posterior view of the temporary implantable prosthesis, and one template 320 provides the medial-lateral view of the temporary implantable prosthesis. The two templates are produced to essentially the same scale as the X-ray photographs, so that the surgeon can lay the templates onto the X-ray photograph in order to find a temporary implantable prosthesis with the best fit to the patient's femur. The surgeon determines which standardized mantle has the most appropriate size and shape to replace the permanent prosthesis fitted to the patient. The surgeon decides whether the standardized mantle will fit within the existing cavity or whether it is necessary to broach the cavity further using the standardized broach that corresponds to the standardized mantle that the surgeon has chosen.

From a set of toothed broaches (400 of Figure 4), the surgeon selects the broach which corresponds to the templates that the surgeon determined best fit the patient's femur. The permanent implant is removed from the patient's infected femur, and the intramedullary canal is debrided of all necrotic tissue and cement. The acetabular component is also removed and all necrotic tissue is debrided. The broach is then inserted into the canal and seated. The position that the broach assumes with respect to the femur demonstrates if the correct broach size has been chosen. If the broach size is incorrect, the broach is removed and a different broach is inserted into the canal and seated. The surgeon also has the opportunity to place the head on the broach and assess the anteversion angle that is needed. Once the correct broach size and appropriate anteversion angle are determined, the surgeon can construct the temporary implantable prosthesis.

Prior to constructing the implant, the components involved in constructing the temporary implantable prosthesis are sterilized. As Figure 5 shows, the two halves 510 and 520 of mold 500 are secured together with four threaded hand knobs 530. The assembled mold has six cavities which correspond to the six standardized mantle portions that this assembly kit makes. The mold 500 is then placed in the base 540 to hold the mold upright. Cement precursor and an optional antibiotic are mixed in a separate container to form a mantle mixture, and a measured amount is poured into the mold cavity which corresponds to the broach selected above. The mantle mixture is a blend of cement precursor (commonly polymethylmethacrylate powder and a liquid monomer such as methyl methacrylate) and, optionally, an antibiotic such as tobramycin. The implant is inserted into the mold, and the proper anteversion angle is set by simply rotating the standardized implant about its long axis in the mold. The mold and implant are designed so that the implant is centered in the mold by its close fit distally with the mold. This preferred embodiment of the invention includes a slight taper on the distal end of the temporary implant and the corresponding female taper in the mold. These features allow the implant to seat with the mold and center the implant. The mantle mixture hardens around the standardized implant to form the standardized mantle portion and the temporary implantable prosthesis. The mantle is molded around the implant prior to insertion into the femur, which allows the temporary implantable prosthesis to be removed easily from the femur at a later date. The two halves of the mold are subsequently separated by releasing the four threaded knobs, and four Allen-drive set screws are used to push the two halves of the molds apart. The temporary implantable prosthesis can then be removed from the mold.

The temporary implantable prosthesis is next inserted and seated into the femur. If necessary, the surgeon uses the broach corresponding to this temporary implantable prosthesis to remove more of the femur to provide the correct fit. Heads can be trialed next by placing a tapered sleeve 600 of Figure 6 over the taper 130 of the temporary implantable prosthesis and fitting one of the trial plastic heads supplied with the kit. The tapered sleeve is selected from a set of e.g. four tapered sleeves of different offset (+0, +5, +10, and +

15) to center the head within the acetabulum, and the correct diameter of head is selected from a set of e.g. four heads (48 mm, 53 nun, 58 mm, and 63 mm diameter) by fitting a plastic head over a tapered sleeve placed on the taper of the temporary implantable prosthesis and placing the plastic head into the acetabulurn and noting its fit. When the tapered sleeve and head size have been determined, the plastic head is removed, and a metal unipolar head of the correct diameter is placed over the tapered sleeve on the taper of the temporary implantable prosthesis. The head is cemented to the tapered sleeve and taper, and the patient's joint is reduced. Alternatively, the head and taper have a Morse taper which joins the head and taper together without cement. Proper range of movement of the patient's leg is checked, and the closing procedure is performed.

Figures 7 A and 7B illustrate a particular design of head that assists in curing the infection of the patient's joint. The head is not solid but is, instead, hollow. Mantle mixture that includes antibiotic is permitted to harden slightly and is packed into the hollow head. Holes in the head allow the antibiotic to diffuse into the acetabulurn. Holes are sized to permit diffusion of antibiotic from the head and into the acetabulurn. The holes are not so large as to weaken the head and allow it to fracture during use.

When antibiotic is incorporated into the mantle mixture, the cement is of sufficient porosity that at least some of the antibiotic incorporated into the cement migrates out of the cement and to the infected joint. The joint is thus treated directly with an antibiotic from the cement. The patient may also receive an antibiotic orally or intravenously to maintain a certain level of antibiotic in the patient to treat the infection, especially once the temporary implantable prosthesis has been within the patient for a few weeks.

The patient can move about more easily and with greater comfort when the patient has a temporary implantable prosthesis of this invention. The patient is thus less susceptible to pneumonia and other opportunistic diseases that could develop if the patient did not have the freedom of movement that the temporary implantable prosthesis helps to provide. As described above, standardized molds and standardized implants are used to make a temporary implantable prosthesis in one embodiment of the invention. Since a temporary implantable prosthesis is used temporarily, the temporary implantable prosthesis does not have to fit perfectly within the femur. The temporary implantable prosthesis needs to fit only sufficiently well that the patient has the ability to move about with crutches or a cane or walker. A standardized mold can be sized and shaped based on e.g. the design for a temporary implantable prosthesis or a standardized mantle, as discussed previously, or on the designer's perceptions of the various sizes and shapes of cavities in patients' femurs. For example, the designer can obtain information on the conurion sizes and shapes of permanent prostheses and perform a statistical analysis to determine standardized sizes and shapes of the mantle and implant. The designer then designs the standardized molds, the standardized broaches, and the standardized implants. Alternatively, standardized molds can be sized and shaped based on a particular supplier's product line, so that the molds supply mantles of approximately the same size and shape as the mantles of the manufacturer's permanent prostheses. Or, standardized molds can be designed to provide standardized mantles which have been designed using any of the methods discussed in this application. A standardized mold can be designed so that the standardized mantle is of the correct length and shape when the standardized mold is filled with mantle material. The size and shape of the standardized broaches is determined from the size and shape of the standardized mantles to be made in the standardized molds.

Other Aspects of the Invention

The embodiment of the invention as described above is one of many embodiments of the invention. Many other embodiments are possible. For example, it is not necessary to add an antibiotic to the cement precursor prior to solidifying the cement precursor about the implant. The mantle of the temporary implantable prosthesis can be coated with antibiotic, or the antibiotic can be eliminated.

Standardized implants can be designed to have a single diameter or oblong profile and a single set of dimensions for their head mounting location (e.g. taper). The length of the implant and the angle that the head mounting location makes to the shaft of the implant are selected by the designer based on the designer's perceptions of the dimensions needed to cooperate with the standardized mantles and provide temporary implantable prostheses of the desired dimensions. As stated above, statistical information can be used to design a set of standardized implants that will provide a large portion of the populace with a functional temporary implantable prosthesis.

The head that attaches to the head mounting location can be a unipolar head in order to simplify the design of the temporary implantable prosthesis. A unipolar head contacts the acetabulurn, just as the head on the femur does. As discussed previously, the unipolar head preferably has holes drilled into the head radially to allow antibiotic to diffuse through the holes and into the joint space cavity, once the antibiotic and cement have been packed into the backside of the head. A unipolar head is widely available, and use of a unipolar head provides the surgeon with a wide variety of options in size of head and offset when fitting the temporary implantable prosthesis to the patient. The mold cavities and the distal end of the standardized implant are preferably non-cylindrical in cross-section to help prevent the implant from rotating within its mantle during use. However, the distal end of the standardized implant and mold cavities could be cylindrical in design. This would allow the standardized implant to be centered in the cavity and would allow axial adjustment of the implant. This design feature would give the surgeon flexibility to position the standardized implant in the mold to provide more vertical offset if needed.

It is not necessary to use a standardized implant. For example, a readilyavailable implant may be inserted into a standardized mold of this invention to form a temporary implantable prosthesis. It is also not necessary to insert the implant into the cavity in the mold prior to inserting the mantle mixture. The mantle mixture can be placed into the cavity first, and the mantle mixture may also be permitted to polymerize substantially prior to placing the insert into the mantle mixture. The mold can be a split mold as illustrated in Figure 1 , or the mold can be a solid, smooth mold having a cavity in which the mantle is cast.

The head may be offset from the centerline of the taper in order to provide the patient with a more comfortable prosthesis. Also, instead of using a unipolar head, the surgeon may choose to use a head which contacts a plastic cup that is inserted into the acetabulurn in order to provide better comfort.

The advantages and examples discussed above are included to illustrate the invention. The scope of the claims is not limited to the preferred embodiments or the examples but is, instead, to be interpreted considering the discussion herein, the figures, the meaning of terms to one of ordinary skill in the art as used or defined herein, and the claims themselves.

Claims

WHAT IS CLAIMED IS:

1. A temporary implantable prosthesis for replacing a permanent prosthesis temporarily, said temporary implantable prosthesis comprising the combination of a standardized mantle and an implant, wherein the standardized mantle has a size and shape that is sufficiently similar to the size and shape of mantle portions of at least two different permanent prostheses that said temporary implantable prosthesis constructed with the standardized mantle substitutes for any of said permanent prostheses, and wherein the implant has a shape and size such that the combination of the standardized mantle and the implant has a size and shape that is sufficiently similar to the size and shape of said permanent prostheses that said temporary implantable prosthesis constructed with the standardized mantle and the implant substitutes for any of said permanent prostheses.

2. The temporary implantable prosthesis of claim I wherein said temporary implantable prosthesis further comprises an antibiotic.

3. The temporary implantable prosthesis of claim 2 wherein the standardized mantle of said temporary implantable prosthesis contains said antibiotic.

4. The temporary implantable prosthesis of claim I wherein said standardized mantle comprises polymethylmethacrylate.

5. The temporary implantable prosthesis of claim I wherein said standardized mantle is made by the method of pouring a mantle mixture into a mold.

6. The temporary implantable prosthesis of claim I wherein said implant comprises a standardized implant, wherein the standardized implant has a shape and size such that the combination of the standardized mantle and the standardized implant has a size and shape that is sufficiently similar to the size and shape of said permanent prostheses that said temporary implantable prosthesis constructed with the standardized mantle and the standardized implant can be used in place of any of said permanent prostheses.

7. A system for making temporary implantable prostheses, wherein the system comprises a first mold and a second mold, wherein the first mold has a size and a shape that is sufficient to make a first standardized mantle which has a size and shape that is sufficiently similar to the size and shape of mantle portions of a first set of permanent prostheses, which set includes two prostheses of different size or different shape, that the temporary implantable prosthesis constructed with the first standardized mantle can be used in place of any of the prostheses of said first set of permanent prostheses; and wherein the second mold has a size and a shape that is sufficient to make a second standardized mantle which has a size and shape that is sufficiently similar to the size and shape of mantle portions of a second set of permanent prostheses, which set includes two prostheses of different size or different shape, that the temporary implantable prosthesis constructed with the second standardized mantle can be used in place of any of the prostheses of said second set of permanent prostheses.

8. The system of claim 7, wherein the kit further comprises at least two standardized implants.

9. The system of claim 7, wherein the kit further comprises a temporary implantable prosthesis construction stand.

10. The system of claim 9, wherein the kit further comprises at least two standardized implants.

11. A method for making a temporary implantable prosthesis, wherein the method comprises the steps of

(a) placing a mantle mixture within a cavity of a mold, wherein the cavity has a size and a shape sufficient to produce a standardized mantle;

(b) placing an implant into the cavity of the mold; and

(c) allowing the mantle mixture to solidify sufficiently that the mantle mixture adheres to the implant and does not run when removed from the mold.

12. The method of claim 11 wherein the step of placing an implant into the cavity of the mold is performed before the step of placing the mantle mixture within the cavity of the mold.

13. A temporary implantable prosthesis made by the method of claim 11.

14. A temporary implantable prosthesis made by the method of claim 12.

15. A temporary implantable prosthesis for replacing a permanent prosthesis in a cavity in a patient's bone during treatment of an infection of a joint of the patient's bone, said temporary implantable prosthesis having a mantle portion and an implant portion, wherein said mantle portion and said implant portion each has a size and a shape such that said temporary implantable prosthesis replaces any of the permanent prostheses which are members of a set of corresponding permanent prostheses, and the shape of said mantle portion is such that little bone has to be removed from the cavity to insert the mantle portion of the temporary implantable prosthesis into said cavity.

16. The temporary implantable prosthesis of claim 15 wherein said temporary implantable prosthesis further comprises an antibiotic.

17. The temporary implantable prosthesis of claim 15 wherein said temporary implantable prosthesis comprises a mantle and an implant.

18. The temporary implantable prosthesis of claim 17 wherein said mantle is made by the method of pouring a mantle mixture into a mold.

19. A method for treating an infected area of a patient's bone comprising

(a) removing a permanent prosthesis from the intramedullary canal in the patient's bone, which cavity is in communication with the infected area;

(b) replacing the permanent prosthesis with the temporary implantable prosthesis of claim 15; and

(c) administering an antibiotic to the patient.

20. The method of claim 19 wherein the step of administering the antibiotic to the patient comprises placing the antibiotic in a mantle portion of the temporary implantable prosthesis, which mantle portion is made of a material which is sufficiently porous that the antibiotic migrates from the mantle portion of the temporary implantable prosthesis and into the intramedullary canal.