Abstract:
The present invention relates to a prosthetic device for placement in an implant area of the body. The prosthetic device comprises an elongated stem portion, a neck portion, and a head portion. Each of the stem, neck, and head portions comprise a material impregnated with an antibiotic agent such that, when the prosthetic device is inserted into the implant area in place of a weight-bearing prosthesis, the antibiotic agent can leach out of the material to fight infection in the implant area. As an added benefit, the structure of the prosthetic device maintains adequate joint spacing in opposition to contraction of the muscles and tendons of the patient over a period of time so that a weight-bearing prosthesis can again be implanted into the implant area after the infection has been overcome.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part of U.S. patent application Ser. No. 08/854,445, filed May 12, 1997 U.S. Pat. No. 5,980,573. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates to a method and apparatus for fighting infection and maintaining joint spacing in a prosthesis implant area of joint replacement patients. More particularly, the present invention relates to a temporary non-weight bearing prosthesis which includes a cementitious substance that is impregnated with an antibiotic agent which will leach out of the substance to fight infection in the implant area. The invention further relates to a method of forming and inserting the temporary non-weight bearing prosthesis into the implant area of the patient such that the joint spacing of the patient is maintained until the time at which a weight bearing prosthesis can be implanted. 
     BACKGROUND OF THE INVENTION 
     Bodily infection is a major concern for patients having implanted structures such as total knee or total hip replacements. In that any object implanted into the human body is foreign, regardless of the duration of time it has existed within the body, infection originating from even remote areas of the body can cause complications with the implanted object. For example, if the patient were to become infected from a rusted nail, the infection likely would spread to the tissue surrounding a joint implant. 
     Several different procedures have been developed in the past to prevent the formation and spread of infection in an implant area. One such procedure has been to administer large doses of antibiotics to the patient in hopes of eradicating the infection all together. Although this procedure is very simple and straightforward, it unfortunately rarely cures the patient of the infection by itself. 
     A more effective solution has been to remove the implant and replace it with some form of spacer containing an antibiotic agent. For example, in the case of total knee replacement patients, physicians often remove the femoral and tibial prostheses and the polyethylene “meniscus” positioned therebetween and replace them with a puck-shaped spacer made of bone cement impregnated with an antibiotic. Typically, the spacer is formed during the operation on a side table in the operating room so that the surgeon can first inspect the joint to determine what size spacer will be needed. After the appropriate size has been ascertained, the surgeon or an assistant simply mixes the constituent elements of the bone cement, typically a polymer and a monomer that will form polymethylmethacrylate, and adds an appropriate amount of antibiotic, typically in powder form. Once the bone cement begins to harden, it becomes malleable and may be shaped by hand to fit within the implant area of the patient where the primary prosthesis had once been. When the spacer has adequately hardened, it is then inserted into the implant area and the incision closed in the conventional manner. 
     Positioned in the implant area, the antibiotic slowly leaches out from the bone cement and into the surrounding tissue to prevent the formation and spread of the infection. While the infection is being fought, typically over a period of 4 to 6 weeks, the bone cement spacer maintains the amount of joint spacing that was present in the implant area prior to removal of the primary prosthesis. If some form of spacer were not placed in the implant area, this joint spacing would be substantially reduced due to the contraction of the muscles and tendons of the patient during the recuperation period. 
     Antibiotic-impregnated bone cement has also been utilized to prevent the formation and spread of infection in total hip replacement patients. In this scenario, the acetabular cup and the hip stem of the primary hip prosthesis are first removed. Next, the surgeon mixes the polymer, monomer, and the antibiotic agent and forms small beads of bone cement. These beads of bone cement are then positioned in a spaced relationship along a length of stainless steel suture wire. Once the bone cement has adequately hardened, the wire, together with the beads, is inserted into the femoral canal to destroy any infection present within the femur. After the infection has been overcome, the surgeon withdraws the beads of bone cement by simply pulling the suture wire out of the femoral canal, carefully counting the number of beads removed to ensure that no beads remain in the femur. 
     Unlike the knee spacer, the bead and suture wire device does not maintain the joint spacing of the implant area since the device does not occupy any of the acetabular cavity that the head and the acetabular cup of the primary hip prosthesis previously occupied. Since the joint will be immobilized and the patient often bedridden for a substantial period of time, contraction of the unused muscles and tendons can cause substantial joint spacing shrinkage. Although this shrinkage is not in itself harmful to the patient, it will shorten the patient&#39;s limb requiring the patient to either walk with a limp or use some form of orthotic device to compensate for the shortened limb. While it is sometimes possible for the physician to stretch the muscles and tendons of the patient to restore some of this lost spacing, it is unlikely that the patient will regain the full amount of joint spacing he or she had before the primary hip prosthesis was removed. 
     Accordingly, it can be seen that it would be desirable to provide a method and apparatus for fighting infection in an implant area of a patient which also maintains adequate joint spacing. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a prosthetic device for placement in an implant area of the body. The prosthetic device comprises an elongated stem portion having a lower distal end and an upper proximal end, a neck portion having a lower distal end and an upper proximal end, the lower distal end of the neck portion being connected to the upper proximal end of the elongated stem portion, the neck portion extending upwardly from the elongated stem portion, and a head portion connected to the upper proximal end of the neck portion. Each of the stem, neck, and head portions comprise a material impregnated with an antibiotic agent such that, when the prosthetic device is inserted into the implant area in place of a weight-bearing prosthesis, the antibiotic agent can leach out of the material to fight infection in the implant area. As an added benefit, the structure of the prosthetic device maintains adequate joint spacing in opposition to contraction of the muscles and tendons of the patient over a period of time so that a weight-bearing prosthesis can again be implanted into the implant area after the infection has been overcome. 
     In addition, the invention relates to a method of preventing the spread of infection and maintaining joint spacing in an implant area of a joint replacement patient that comprises examining the implant area to determine the size and extent of the joint spacing, selecting a prosthetic device comprising antibiotic-impregnated material and sized to fit within the implant area such that, once inserted within the implant area, little or no space is left between the prosthetic device and the surrounding tissue of the implant area, the pre-formed temporary hip prosthesis having an elongated stem, a neck portion, and a head. The prosthetic device is then inserted into the implant area such that the antibiotic can leach out of the antibiotic-impregnated material to fight infection and to maintain adequate joint spacing in opposition to contraction of the muscles and tendons of the patient so that a weight-bearing prosthesis can be implanted into the implant area after the infection has been overcome. 
    
    
     The features and advantages of the present invention, will become apparent upon reading the following detailed description, when taken in conjunction with the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view, partially in section of a pre-formed temporary hip prosthesis. 
     FIG. 2 illustrates a cross-sectional view of the pre-formed temporary hip prosthesis shown in FIG.  1 . 
     FIG. 3 is a perspective view of a threaded aperture of an alternative embodiment of the pre-formed temporary hip prosthesis. 
     FIG. 4 is a perspective view of a prosthesis frame. 
     FIG. 5 is a side view of the prosthesis frame shown in FIG.  4 . 
     FIG. 6 is a front view of the prosthesis frame shown in FIGS. 4-5. 
     FIG. 7 is a cross-sectional view of a stem portion of the prosthesis frame shown in FIGS. 4-6. 
     FIG. 8 is a perspective view of an alternative configuration of the stem portion of the prosthesis frame. 
     FIG. 9 is a perspective view of an elongated removal tool. 
     FIG. 10 is a perspective view of threaded removal tool. 
     FIG. 11 is a perspective view of a mold used with the prosthesis frame shown in FIGS. 4-7. 
     FIG. 12 shows the prosthesis frame of FIGS. 4-7 in use with the mold of FIG.  11 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now in greater detail to the drawings in which like numerals indicate corresponding parts throughout the several views, FIG. 1 illustrates an embodiment of a pre-formed temporary hip prosthesis  10  to be inserted in place of a weight bearing hip prosthesis of a total hip stem replacement patient. As shown in the figure, the pre-formed temporary hip prosthesis  10  comprises an elongated stem portion  12 , a neck portion  14 , and a head portion  16 . The elongated stem portion  12  typically is substantially cylindrical in shape and has a lower distal end  18  and an upper proximal end  20 . Where the shape selected is cylindrical, the elongated stem portion  12  can be tapered along its length and usually will have a substantially circular cross-section as depicted in FIG.  2 . 
     Similar to the elongated stem portion  12 , the neck portion  14  has a lower distal end  22  and an upper proximal end  24 . As shown most clearly in FIG. 1, the neck portion  14  extends from the upper proximal end  20  of the elongated stem portion  12  at an angle to simulate the configuration of a human femur. The neck portion  14  can be formed substantially cylindrically as indicated in FIG. 1, or may take any other shape which would substantially simulate the function of a human femur. 
     The head portion  16  of the prosthesis  10  is formed on the upper proximal end  24  of the neck portion  14 . Typically, the head portion  16  is substantially spherical, forming a bulbous head which simulates a femoral head of a human femur. It is to be understood, however, that the head portion could be formed in any shape which would adequately fill the patient&#39;s acetabular cavity to maintain the joint spacing of the implant area. 
     In a preferred arrangement, the pre-formed temporary hip prosthesis  10  will include a collar  26  formed at the juncture of the neck portion  14  and the elongated stem portion  12 . When provided, the collar  26  is substantially disk-shaped and forms an acute angle with respect to the elongated stem portion  12  as depicted in FIG.  1 . The pre-formed temporary hip prosthesis  10  normally further is cannulated, i.ee., provided with an elongated canal  28  which is adapted to accept an elongated removal tool  32 , described in more detail below, to facilitate removal of the temporary hip prosthesis from the body. The elongated canal  28  extends from the upper proximal end  20  to the lower distal end  18  of the elongated stem portion  12 . As illustrated in FIG. 2, the elongated canal  28  may be a substantially cylindrical aperture formed concentrically with the elongated stem portion  12 . 
     As is illustrated in FIG. 3, the pre-formed temporary hip prosthesis  10  can be provided with a threaded aperture  30  in the upper portion  20  of the elongated stem portion  12  in exception or in addition to the elongated canal  28 . The threaded aperture  30  is sized and configured to accept a threaded removal tool  38 , discussed in more detail below, which may be used to facilitate removal of the pre-formed temporary hip prosthesis. 
     Each of the elongated stem portion  12 , neck portion  14 , and head portion  16  typically is composed of a bone cement such as polymethylmethacrylate (“PMMA”), commonly referred to as methylmethacrylate. These portions can be formed together in a single mold to form a one-piece temporary hip prosthesis, or separately with each portion being connected together at a later time. Accordingly, the pre-formed temporary hip prosthesis  10  can be unitary or modular in construction. In either case, bone cement is presently preferred because it is approved by the FDA for implantation into the human body. 
     Regardless of the particular material chosen for fabrication of the pre-formed temporary hip prosthesis  10 , the material contains an antibiotic agent. It is currently anticipated that the antibiotic agent will impregnated into the material by simply mixing in an appropriate amount of antibiotic with the constituent elements of the material during the formation process of the temporary hip prosthesis  10 . However, it will be understood that other methods of impregnation may be used, for example, soaking a porous, temporary hip prosthesis in a liquid antibiotic. 
     When it is determined that a joint replacement patient has contracted an infection, the physician must first determine if the primary prosthesis should be removed. If such removal is warranted, a surgeon will remove the entire prosthesis. In the case of a total hip replacement patient, removal will include the extraction of both the hip stem fixed within the canal of the femur and the acetabular cup fixed to the patient&#39;s pelvis. Once these components of the primary prosthesis have been removed, the surgeon will inspect the implant area to check for signs of infection and will determine the size and extent of the joint spacing of the patient. The magnitude of this spacing will vary with the size of the patient and with the size of the primary prosthesis which had previously occupied the implant area. After the size of the joint spacing has been ascertained, the physician may then select the correctly sized pre-formed temporary hip prosthesis for the particular patient. Typically, the physician will be provided with a variety of differently sized prostheses to more closely match the temporary hip prosthesis with the patient. In particular, the physician will have available several different sizes of stem portion diameters with which to choose from. Moreover, the physician will also be able to choose a preformed temporary hip prosthesis having a desired concentration of antibiotic impregnated therein. To simplify the selection process, it is preferred that each preformed temporary hip prosthesis is prepackaged in a sterile packet or container having indicia or other coding indicating the size of the prosthesis contained therein and its antibiotic concentration. 
     Once the selected pre-formed temporary hip prosthesis has been removed from its packaging, the prosthesis may be altered by the surgeon or surgical assistant to more closely correlate to the anatomy of the patient. Typically, the elongated stem portion  12  is approximately 200 to 250 mm long and the head portion has a radius of approximately 44 to 48 mm in length. Since the elongated stem portion  12  is substantially longer than the typical primary prosthesis stem, the elongated stem portion most often must be trimmed so that the length of the stem portion measured from the collar approximates the depth of the femoral canal of the patient. Trimming may be accomplished by cutting the elongated stem portion  12  with a common surgical tool such as a bone saw. Due to the heat formed during the cutting process, the opening of the elongated canal of the elongated stem portion typically needs to be reformed to remove any bone cement that has fused the opening shut. In that the head portion  16  of the temporary prosthesis is substantially larger than the typical femoral head of a primary prosthesis, it also may need to be reduced in size. However, since both the hip stem and the acetabular cup of the primary hip prosthesis will have been removed, it is anticipated that a large head portion will be needed in most applications to ensure that the full joint spacing is maintained. In fact, the surgeon may even need to increase the size of the head portion by adding on additional antibiotic-impregnated bone cement. 
     After the temporary hip prosthesis  10  has been trimmed and/or reshaped to the proper extent, the temporary hip prosthesis is inserted into the implant area. Specifically, the elongated stem portion  12  is inserted into the canal of the femur with the head portion  16  placed in the acetabular cavity of the hip. Overinsertion into the femoral canal is prevented with the collar  26 , this collar abutting the top surface of the femur when the temporary hip prosthesis is fully inserted. The collar  26  furthermore prevents the temporary hip prosthesis  10  from creeping down into the canal during the recuperation period against the contractive force of the patient&#39;s tightening muscles and tendons. 
     Once the insertion procedure has been completed, the joint is immobilized and the patient being either bedridden or, at minimum, prohibited from putting weight on the joint in which the temporary hip prosthesis is provided. It is important that the patient be prevented from placing weight on the joint in that the temporary hip prosthesis is typically formed exclusively from bone cement which is far more brittle than the metals conventionally used in primary hip prostheses. However, it is to be noted that the temporary hip prosthesis is strong enough to withstand the contraction of the surrounding muscles and tendons of the patient during the recuperation period. During this time, the temporary hip prosthesis will be left in place, with the antibiotic agent impregnated into the bone cement leaching out to the surrounding tissue, preventing the formation of the infection in the implant area or destroying the infection if it had already formed. 
     Once the physician is satisfied that the infection has been overcome, the preformed temporary hip prosthesis  10  may be removed. Although the temporary hip prosthesis is not fixed in place in the manner in which primary prostheses are, tissue growth in the femoral canal may create difficulty in removing the temporary hip prosthesis. In cases in which the temporary hip prosthesis is provided with an elongated canal  28 , an elongated removal tool  32  such as that depicted in FIG. 9 may be used to aid in the removal process. As shown in the figure, the removal tool can, for instance, be in the form of an elongated shaft  33  having a handle  34  and split ends provided with hooks  36  which, when inserted into the canal, are biased to spring out at the lower distal end  18  of the elongated stem portion  12  when the elongated removal tool is passed therethrough to firmly engage the temporary hip prosthesis. Once secured in this manner, the surgeon can remove the prosthesis simply by pulling it out with the handle  34 . Alternatively, in cases in which the temporary hip prosthesis  10  is provided with a threaded aperture  30  at the upper proximal end  20  of the elongated stem portion  12 , the temporary hip prosthesis may be removed with the aid of the threaded removal tool  38  depicted in FIG.  10 . As illustrated in the figure, the threaded tool  38  can, for instance, take the form of a threaded bolt  40  provided with a handle  42 . To remove the temporary hip prosthesis  10 , the threaded tool  38  is threaded into the threaded aperture  30  and then the temporary hip prosthesis is pulled out from the femur by pulling outwardly on the handle  38 . After the pre-formed temporary hip prosthesis has been removed, the femoral canal is then carefully cleaned with a lavage to ensure that no bone cement remains in the femur. At this point, a primary, weight bearing hip prosthesis may again be implanted in the patient&#39;s hip. 
     Although the above described pre-formed temporary hip prosthesis would function well to fight infection and maintain joint spacing in the implant area, approval has not yet issued from the FDA for the commercial manufacture of products formed solely of antibiotic-impregnated bone cement. Accordingly, until such approval is obtained, an interim solution to the problem is needed. The second embodiment of the invention provides such a solution. In this embodiment of the invention, the physician is provided with a prosthesis frame  44  such as that depicted in FIGS. 4-6. As illustrated in these figures, the hip prosthesis frame  44 , similar to the pre-formed temporary hip prosthesis  10 , comprises an elongated stem portion  46 , a neck portion  48 , and a head portion  50 . Furthermore, the elongated stem portion  46  has a lower distal end  52  and an upper proximal end  54 . Similarly, the neck portion  48  also has a lower distal end  56  and an upper proximal end  58 , the neck portion  48  extending upwardly from the upper proximal end  54  of the elongated stem portion  46  at an angle to simulate the shape and configuration of a human femur. As shown in FIG. 5, the head portion  50  is connected to the upper proximal end  58  of the neck portion  48 . In addition, the prosthesis frame  44  is provided with a collar  60  positioned at the juncture of the neck portion  48  and the elongated stem portion  46 . Included on the collar  60  is an upper surface  62  which faces the head portion  50 . Like the pre-formed temporary hip prosthesis, the prosthesis frame will typically be formed from bone cement. 
     Unlike the pre-formed temporary hip prosthesis  10 , however, the elongated stem portion  46  of the prosthesis frame  44  is provided with a plurality of radial flanges  64  which extend from a central axis of the elongated stem portion. Although the elongated stem portion  46  is shown in FIGS. 4-7 as having four radial flanges  64 , it is to be understood that a lesser or greater of radial flanges could be provided, as desired. As shown in these figures, the radial flanges  64  extend substantially along the entire length of the elongated stem portion  46 . Configured in this manner, the radial flanges  64  provide a plurality of elongated recesses  66  which extend from the central axis of the elongated stem portion  46  to the outer edges  68  of each radial flange  64 . These elongated recesses  66  are adapted to receive and support a hardenable material, such as bone cement, which is impregnated with an antibiotic. Thus, the frame  44  functions as the endoskeleton for the end product, and the stem portion  46  functions as a stem support for the stem of the final product. 
     As illustrated in FIGS. 4-6, the head portion  50  comprises a substantially circular base portion  70  having a top surface  72  and an outer edge  73 . Positioned atop the top surface  72  is a plurality of arcuate flange members  74  which extend upwardly from the top surface  72  and preferably meet along a central axis normal to the circular base portion  70 . It is to be noted that although the head portion  50  is shown as having four flanges members  74 , like the flanges  64  of the stem portion  46 , a lesser or greater number of flange members could be used, as desired. Similar to the radial flanges  64 , the arcuate flange members  74  provide a plurality of recesses  76  which extend outwardly toward the outer edges of the circular base portion  70  and each arcuate flange member  74 . These recesses  76  also are adapted to receive and support a hardenable material, such as bone cement, which is impregnated with an antibiotic. Therefore, the head portion  50  functions as a ball support, for supporting the final ball that is formed on the prosthesis frame. 
     The prosthesis frame  44  may also be provided with means for facilitating its removal from the femoral cavity once the infection has been overcome. As illustrated in FIGS. 5 and 7, the elongated stem portion  46  of the prosthesis frame  44  typically is provided with an elongated canal  78  which extends from the upper proximal end  54  to the lower distal end  52  of the elongated stem portion  46 . Although it is preferable to provide the prosthesis stem portion  46  with such a canal  78 , the prosthesis frame  44  could alternatively be provided with a threaded metal sleeve (not shown) placed in the upper proximal end  54  of the elongated stem portion to provide a threaded aperture similar to threaded aperture  30  of the pre-formed temporary hip prosthesis  10  described above. 
     FIG. 8 depicts an alternative arrangement of the elongated stem portion  46  of the prosthesis frame  44 . In this embodiment, the elongated stem portion  80  is provided with curved radial flanges  82  formed from concave channels  84  extending along the length of the elongated stem portion  80  such that the elongated stem portion has a substantially star-shaped cross-section. Each of the concave channels  84  provide elongated recesses  86  which, similar to the above described recesses, may be filled with antibiotic-impregnated bone cement. As with the first configuration of the elongated stem portion  46  of the prosthesis frame, the alternative elongated stem portion  80  also can be provided with an elongated canal  88  or a threaded sleeve (not shown) to facilitate removal of the temporary prosthesis after the infection has been overcome. Although not depicted in the figures, the arcuate flange members  74  of the head portion  50  likewise can be formed from concave surfaces, if desired. When the frame is formed with curved radial flanges and curved arcuate flange members as described above, less antibiotic-impregnated hardenable material and less time will be required to form the temporary prosthesis. 
     The prosthesis frame is used in a manner similar to that of the pre-formed temporary hip prosthesis. When it is determined that a joint implant must be removed due to infection, the physician removes the entire prosthesis and inspects the implant area to determine the size and extent of the joint spacing of the patient. After the size of the joint spacing has been ascertained, the physician then selects a prosthesis frame appropriate for the particular application. It is anticipated that only one size prosthesis frame will be required for each application whether it be a hip stem prosthesis frame, knee prosthesis frame, or otherwise. It will be understood, however, that a variety of differently sized prostheses could be made available to the physician to more closely match the particular patient. Like the pre-formed temporary hip prosthesis described above, each prosthesis frame is prepackaged in a sterile packet or container having indicia or other coding that indicates the size and antibiotic concentration of the prosthesis contained therein. 
     Once the appropriate prosthesis frame  44  has been selected, it can be altered by the surgeon or surgical assistant to more closely correlate to the particular patient. In the case of a hip prosthesis frame described above, the elongated stem portion is normally approximately 200 to 250 mm long, and the outer edges of the circular base portion  70  and the arcuate flanges  74  will form the outline of a semi-sphere having a radius approximately 44 to 48 mm in length. Most often, the elongated stem portion will need to be trimmed so that its length approximates the depth of the femoral canal of the patient. Where the prosthesis frame is provided with an elongated canal, the opening of the canal may need to be reformed due to fusion of the opening resulting from heat formed during the cutting process. 
     After the temporary hip prosthesis frame  44  has been trimmed, an antibiotic-impregnated hardenable material can be manually applied to the recesses  66  and  76  of the prosthesis frame. The hardenable material, preferably PMMA bone cement, is liberally applied in the recesses  66  and  76  until it is substantially flush with the outer edges of the radial flanges, the circular base portion, and the arcuate flange members thereby forming a temporary hip prosthesis having a substantially cylindrical shank and a substantially bulbous head. In addition, the neck portion of the frame between the collar and the base portion may also be provided with antibiotic-impregnated bone cement, if desired. To simplify the process of applying the antibiotic-impregnated hardenable material to the hip prosthesis frame  44 , a mold  90  can be used by the surgeon or surgical assistant. As shown in FIG. 11, this mold can comprise a body portion  92  having a top  94  and a base to  96 . Formed in the top  94  of the body portion  92 , is an opening  98  that leads to an inner cavity  100  (FIG.  12 ). As is illustrated in the cross-sectional view of FIG. 12, this inner cavity  100  is sized and configured so as to receive the head portion  50  of the prosthesis frame  44  with little clearance. With this arrangement, the entire head portion  50  of the prosthesis frame can be disposed within the inner cavity  100  to apply to the hardenable material to the recesses  76  formed therein. To accomplish this application, the inner cavity  100  of the mold  90  is filled with uncured hardenable material and the head portion  50  of the prosthesis frame  44  dipped into the cavity such that the recesses  76  are filled with the uncured hardenable material. The prosthesis frame  44  then can be left in this position relative to the mold  90  until the hardenable material fully cures. At this point, the prosthesis frame  44  can be removed from the mold  90  with the hardeanble material filling the recesses  76  such that the head portion is configured as a substantially bulbous head that is substantially flush with the outer edges of the arcuate flanges  74 . 
     Once the hardenable material has adequately cured, the newly formed temporary hip prosthesis, or other non-weight bearing temporary prosthesis, is inserted into the implant area. Next, the limb will be immobilized to prevent the patient from putting weight on the joint. As with the pre-formed temporary hip prosthesis  10 , the temporary prosthesis formed from the prosthesis frame  44  will be left in place for several weeks during which time the antibiotic will leach out to the surrounding tissue to destroy the infection. Once the infection has been eradicated, the temporary prosthesis may be removed. In cases where the temporary prosthesis is a hip prosthesis provided with an elongated canal  78  or  88 , an elongated removal tool  32  similar to that depicted in FIG. 9 may be used to aid in the removal process. Alternatively, in cases in which the temporary hip prosthesis is provided with a threaded sleeve at the upper proximal end  54  of the elongated stem portion, the temporary hip prosthesis may be removed with the aid of the threaded removal tool  38  depicted in FIG.  10 . 
     In an alternative method of fighting infection and maintaining joint spacing in an implant area, a temporary prosthesis is formed by the surgeon with the use of a prosthesis mold. After the size of the joint spacing has been ascertained, the surgeon or a surgical assistant selects a prosthesis mold which is configured to produce a temporary prosthesis of a size appropriate for the particular infected patient. It is anticipated that a variety of differently sized prosthesis molds could be made available to the surgical staff to closely match the patient&#39;s anatomy. Once the appropriate prosthesis mold has been selected, the surgeon or surgical assistant mixes the hardenable material with a predetermined amount of antibiotic and fills the mold such that the entire inner space of the mold is occupied with antibiotic-impregnated hardenable material. Once the material has adequately hardened, the newly formed temporary prosthesis can be removed and shaped, if necessary, to accommodate the implant patient. At this point, the temporary prosthesis is inserted into the implant area in accordance with the above described methods. 
     While the forgoing invention has been described in the form of preferred embodiments and procedures, it will be understood by those skilled in the art that numerous modifications, variations, and changes, can be made thereto without departure from the spirit and scope of the invention as set forth in the following claims.