WO2000001324A1

WO2000001324A1 - Membrane for use with prosthetic devices

Info

Publication number: WO2000001324A1
Application number: PCT/US1999/004278
Authority: WO
Original assignee: Buttermann, Glenn, R.
Priority date: 1998-07-07
Filing date: 1999-03-26
Publication date: 2000-01-13
Also published as: AU3065099A

Abstract

A prosthetic joint apparatus (10, 50, 78) for replacement of a damaged natural joint in a patient's body includes a first prosthetic component (12, 52, 80) for securing to a first bone and a second prosthetic component (14, 54, 82) for securing to a second bone. The first and second prosthetic components have engaging, articulating surfaces to permit relative movement between the first bone and the second bone. A first membrane (28, 62, 88) is attached to the first prosthetic component between an intra-articular section (A) and an extra-articular section (B) of that first prosthetic component. The second membrane (30, 64, 94) is attached to the second prosthetic component between an intra-articular section (A) and an extra-articular section (B) of that second prosthetic component. The first and second membranes are impermeable to wear debris and prevent migration of any wear debris from the intra-articular sections (A) to the extra-articular sections (B) of the prosthesis (10, 50, 78).

Description

MEMBRANE FOR USE WITH PROSTHETIC DEVICES

Background of the Invention

This invention relates to a novel membrane for use with prosthetic implants, such as prosthetic joints. More specifically, this invention relates to a membrane for attachment to a prosthetic component to create a barrier between the joint and the implant/bone interface. Prosthetic joint replacement generally has proven to be a successful orthopaedic procedure. Mechanical and structural failure of joint prosthesis have decreased with new developments in design and materials. However, reasons for prosthetic joint failure other than mechanical and structural failure have now become prevalent . A current mode of prosthetic joint failure occurs when a prosthetic component loosens at the implant/bone interface. Not unexpectedly, the articulating surfaces of a prosthetic joint create wear debris over extended periods of time. This wear debris may migrate to the extra-articular implant/bone interfaces and result in a biological response, which in turn may lead to bone resorption or osteolysis. Figure 6 illustrates possible migratory pathways of wear debris generated by the articulating surfaces AS of a hip prosthesis (pathways indicated by arrows) . If the magnitude of osteolysis around the prosthetic joint is sufficient, then degradation of the implant/bone interface may occur, ultimately resulting in a loosening of the prosthetic components from bone. Osteolysis or a loose prosthetic component can lead to pain, loss of function, and bone fracture . In order to contain the particulate wear debris and prevent it from migrating to the extra-articular implant/bone interface regions, a number of fully encapsulating membranes have been developed. For example, U.S. Patent No. 4,731,088 describes a flexible enclosure membrane that fully encloses the articulating surfaces of a ball-in-socket prosthetic joint. Similarly, European Patent Publication No. EP-A-0346294 describes a flexible sheath, fitted around the articulating components of a total hip endoprosthesis . A modified version of an encapsulating membrane is disclosed in U.S. Patent No. 5,514,182; this encapsulating membrane includes ring supports that prevent the membrane from becoming entrapped between the articulating surfaces of the prosthetic joint. U.S. Patent No. 3,683,421 to Martinie discloses a membrane that fully encapsulates and seals the articulating components of a hip prosthesis to seal in lubricant and wear debris and seal out corrosive body fluids .

In addition to those designed to address the problem of wear debris, encapsulating membranes have been developed for other purposes . U.S. Patent No. 3,864,758 discloses an encapsulating hip joint bearing prosthesis that has a lubricating fluid cavity to provide frictionless joint movement. This prosthesis prevents residue from body fluids from penetrating between the joint surfaces, where the residue could solidify, cause rough spots, and increase wear and tear of the joint. A fully encapsulated, flexible joint is disclosed in U. S . Patent No. 3,739,403 to Nicolle and includes a capsule that protects the hinged portion of the prosthetic from ingrowing body tissues. Fully encapsulating membranes, however, have some drawbacks. These membranes are bulky, which makes implantation of the prosthesis difficult. If the membrane is too bulky, its size may limit the range of motion of the prosthetic joint. Also, in some fully encapsulating membranes, the membrane may become entrapped between the articulating surfaces of the prosthesis .

Another approach to preventing wear debris from migrating to the extra-articular implant/bone interface is to treat the portion of the implants directly adjacent to the articulating components of the implant with surface treatments for promoting fibrous tissue attachment to the components, as disclosed in U.S. Patent No. 5,702,483 to Kwong . The fibrous tissue forms a capsule between and around the components. Any wear debris created by the articulating surfaces rubbing together is confined within the capsule. This type of fibrous capsule, however, may limit the range of motion of the prosthetic joint.

The difficulties suggested in the preceding are not intended to be exhaustive but rather are among many which tend to reduce the effectiveness of prior medical apparatuses used with prosthetic joints to prevent the migration of wear debris into an implant/bone interface. Other noteworthy problems may also exist; however, those presented above should be sufficient to demonstrate that such apparatuses appearing in the past will admit to worthwhile improvement .

Summary of the Invention

Accordingly, it is a general object of the invention to provide a membrane for use with a prosthetic device that will obviate or minimize difficulties of the type previously described. It is a specific object of the invention to provide a membrane for use with a prosthetic device that operates as a barrier to prevent wear debris from migrating or translocating to extra-articular prosthetic joint sites. It is another object of the invention to provide a membrane for use with a prosthetic device that decreases the likelihood of loosening of a prosthetic component from bone .

It is still another object of the invention to provide a prosthetic device that is easy and relatively inexpensive to manufacture, has few parts, may be retrofit to a particular operative site, and is biocompatible .

A preferred embodiment of the invention which is intended to accomplish at least some of the foregoing objects includes a membrane for use with a prosthetic device having an inner periphery for attachment around a prosthetic component at the juncture of the intra- articular section and the extra-articular section, an outer periphery for extending away from the prosthetic component, a porous region facing the extra-articular section for tissue ingrowth, and a nonporous region impermeable to wear debris generated by articulating surfaces of the prosthetic device. The porous region preferably has a pore size of at least 20 microns.

In one embodiment, a porous surface of the membrane faces the extra-articular section, and a nonporous surface faces the intra-articular section. The nonporous surface may be smooth. The nonporous surface prevents fibrous tissue ingrowth into the prosthetic joint.

In another embodiment, a first surface and an opposite, second surface of the membrane are porous, and the nonporous region is interposed between the first and second surfaces. The membrane of this embodiment may be a composite or it may be layered, with first and second porous layers and a third nonporous layer interposed therebetween. The membrane preferably is toroidal in shape. However, it may also be manufactured in the form of a strip and then trimmed to fit around a prosthetic component . The membrane preferably has a width of about 1.0 to 2.0 cm. Once in place on the prosthetic component, the outer periphery preferably curves away from the articulating surfaces so that the membrane is not caught between the surfaces and does not interfere with joint activity. The membrane is composed of a biocompatible material and may be selected from the group consisting of polytetrafluoroethylene and polyethylene terephthalate . The membrane has a thickness of at least 0.5 mm., preferably between about 0.5 to 2.0 mm. A method of manufacturing a prosthetic that prevents migration of wear debris to implant/bone interfaces in accordance with the invention comprises the steps of: providing first and second prosthetic components, each having an intra-articular section and an extra-articular section; affixing a first membrane to the first prosthetic component at the juncture of the intra- articular section and the extra-articular section of the first prosthetic component so that the first membrane extends out from the first prosthetic component; and affixing a second membrane to the second prosthetic device at the juncture of the intra-articular section and the extra-articular section of the second prosthetic component so that the second membrane extends out from the second prosthetic component . The membranes each have a porous portion for tissue ingrowth that faces the extra-articular section of the respective prosthetic component and a nonporous portion for preventing migration of wear debris through the membrane.

A method of implanting a prosthetic device that prevents migration of wear debris into implant/bone interfaces may comprise the steps of: providing a first prosthetic component having a first membrane affixed thereto, the first membrane being impermeable to wear debris; providing a second prosthetic component having a second membrane affixed thereto, the second membrane being impermeable to wear debris; implanting into a first bone the first prosthetic component so that the first membrane extends over an interface between the first prosthetic component and the first bone; and implanting into a second bone the second prosthetic component so that the second membrane extends over an interface between the second prosthetic component and the second bone, the first membrane and the second membrane preventing passage therethrough of wear debris generated by articulating surfaces of the first prosthetic component and the second prosthetic component. The membranes may be used in conjunction with hip, shoulder, and knee prosthetics, as well as other prosthetic devices where migration of wear debris is a problem.

The invention may also be used in hemiarthroplasty, where only half a natural joint component is damaged and requires replacement. In such a case, a prosthetic joint component in accordance with the invention comprises a prosthetic component secured to a first bone, and a membrane for attachment to the prosthetic component between an intra-articular section and an extra-articular section of the prosthetic component. The membrane has a porous surface facing the extra-articular section and is impermeable to wear debris to prevent migration of wear debris from the intra-articular section to the extra-articular section.

Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims. Brief Description of the Drawincrs

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate a presently preferred embodiment of the invention, and, together with the general description given above and the detailed description of the preferred embodiment given below, serve to explain the principles of the invention.

Figure 1 is an exploded, perspective view of a disarticulated total hip prosthesis which includes a first membrane attached to an acetabular component and a second membrane attached to a femoral component in accordance with the invention;

Figure 2 is a top, plan view of a strip-type membrane in accordance with the invention;

Figures 3A-3C are enlarged side views, in cross section, of alternative embodiments of the strip-type membrane of Figure 2 in accordance with the invention;

Figure 4 is an exploded, perspective view of a disarticulated total knee prosthesis which includes a first membrane attached to a tibial component, a second membrane attached to a femoral component, and a third membrane attached to a patellar component in accordance with the invention; Figure 5 is an exploded, perspective view of a disarticulated total shoulder prosthesis which includes a first membrane attached to a humeral component and a second membrane attached to a glenoid component in accordance with the invention; and Figure 6 is a cut away, schematic view of a hip prosthesis and shows the possible migration pathways of wear debris into the implant/bone interface regions. Detailed Description of the Preferred Embodiments

With reference to the drawings, wherein like numerals indicate like parts, and initially to Figure 1, a disarticulated total hip prosthesis is depicted, with a membrane encircling, and extending out from, each prosthetic component. The membranes extend out from the prosthetic components like a skirt or cuff. The membranes create a barrier between the joint and the implant/bone interface; that is, between the joint cavity and the interface between the prosthetic component and bone and, where the implant is secured in place by bone cement, between the joint cavity and the interface between cement and bone. This membrane barrier prevents wear debris that is generated by the articulating surfaces of the prosthetic from migrating to the implant/bone interface. By preventing this migration, the barrier effectively reduces osteolysis of bone at the implant/bone (implant/cement/bone) interface and any consequent loosening of the implant from bone. The total hip prosthesis, generally indicated 10, has a femoral component 12 and an acetabular component 14. The hip prosthesis 10 is used to replace a damaged natural hip joint. The acetabular component 14 conventionally includes a bone (or cement) fixation surface 16 and a liner 17. The femoral component 12 conventionally includes a head 20, a neck 22, and a stem 24. The head 20 and an inner portion 26 of the liner 17 provide the articulating surfaces of the hip prosthesis. The articulating surfaces permit relative movement between a patient's femur and pelvis.

A first membrane 28 is positioned around, and extends outward from, the femoral component 12 to demarcate a dividing line between an intra-articular section and an extra-articular section of the femoral component 12. The intra-articular section is indicated by arrow A, and the extra-articular section is indicated by arrow B. These arrow indicators will be maintained for all of the embodiments of the present invention.

In the case of the femoral component 12, the neck 22 separates the intra-articular section from the extra- articular section. The first membrane 28 is shown here mounted to the base of the neck 22. However, the membrane 28 may be mounted at any position along the neck 22 between the head 20 and the stem 24, consequently shifting the dividing line between the intra-articular and extra-articular sections of the femoral component 12.

A second membrane 30 is positioned around, and extends outward from, the acetabular component 14 to separate the intra-articular section (arrow A) from the extra-articular section (arrow B) . Some acetabular components, such as the one shown in Figure 6, includes a liner 17 covered by a metal base 18. The metal base 18 is mounted to the pelvic bone. In such an acetabular component, the second membrane 30 may be mounted either to the outer periphery of the base 18 or to an outer periphery of the exposed portion of the liner 17. Other acetabular components include only a liner 17, and no metal base, in which case the second membrane 30 is mounted to an outer periphery of the liner 17. The membranes, in combination, prevent migration of wear debris to the implant/bone interfaces. The term "implant/bone interface" will be understood to cover both the situation where the implant directly abuts bone and where the implant is separated from, yet secured to, the bone by bone cement .

The membranes 28 and 30 are preferably toroidal in shape and encircle the respective prosthetic component. The membranes have an inner periphery for attachment to the prosthesis and an outer periphery that extends out from the prosthesis. This outer periphery preferably curves away from the articulating surfaces of the prosthesis so that the membrane does not get caught between the articulating surfaces or interfere with joint function. The membranes may be attached to the respective prosthetic components by adhesives, bonding agents, cement, clamps, interdigitation, or a frictional device.

The membrane material should be flexible and amenable to cutting or trimming to size, as deemed necessary by the operating surgeon for a particular patient and operative site. Accordingly, the membrane material should not fray, unravel, or otherwise come apart if it is cut. Suitable biocompatible materials that may be used as a membrane material include polytetrafluoroethylene, for example PTFE manufactured by W.L. Gore & Associates and sold under the trademark PRECLUDE^® Spinal Membrane, and polyethylene terephthalate, for example polyester DACRON™ manufactured by DuPont .

As an alternative to a toroidally-shaped membrane, the membrane may be manufactured as a strip and cut to size by the surgeon. The strip, prior to trimming, may be straight or curved. Figure 2 shows a curved strip 31 that has two ends 33, an inner periphery 35, and an outer periphery 37. The strip 31 is attached at its inner periphery 35 to a prosthetic component by circling the strip around the prosthetic component and attaching the strip's two ends 33 together. This strip-type membrane may be trimmed and fit to a prosthesis to suit a particular operative environment. For example, the strip may be trimmed to fit the hip prosthesis of a small person.

The membranes preferably have a thickness of at least 0.5 mm, and preferably between 0.5 mm and 2.0 mm, and, when implanted, a width of about 1.0 to 2.0 cm. The width of the membrane is of a sufficient distance to cover the implant/bone interface. In addition, either membrane shape, toroidal or strip-type, may be attached to the prosthesis by the manufacturer. A surgeon could then trim the already-attached membrane down to size as appropriate .

When implanted, the first and second membranes 28 and 30 prevent migration of wear debris generated by the articulating surfaces of the hip prosthesis into areas where the prosthesis interfaces with bone, i.e., implant/bone interfaces. Each membrane has a first surface 32a, 32b that faces away from the articulating joint (and thus toward the extra-articular section of the prosthesis) and a second surface 34a, 34b that faces toward the articulating joint (and thus toward the intra- articular section of the prosthesis) .

First surfaces 32a, 32b are porous to allow ingrowth of the surrounding fibrous tissue. The pore size of the porous surface is preferably between 20 microns and 500 microns. Once securely attached to the surrounding tissue, the membranes act as a barrier to prevent wear debris from migrating or translocating to extra-articular sections of the prosthetic joint. Particulate wear debris associated with osteolyses may range in size from 5 microns to less than 0.5 microns. Because of the small size of the wear debris, it is essential that the membrane have a nonporous portion; that is, a portion impermeable to wear debris. This nonporous portion prevents passage of wear debris through the membrane from the intra-articular section to the extra-articular section. In the embodiment shown in Figure 1, second surfaces 34a and 34b of membranes 28 and 30, respectively, are nonporous. Figures 3A-3C illustrate cross-sectional views of possible membrane embodiments in accordance with the invention. These figures show a side view in cross section of the strip-type membrane; however, it should be understood that the toroidally-shaped membrane may also take the form of any of the embodiments shown. The membranes are mounted to prosthesis surfaces 36a, 36b, and 36c, respectively, in accordance with the invention. As above, arrow A indicates the direction toward the intra-articular section, and arrow B indicates the direction toward the extra-articular section of the prosthesis . The membrane of Figure 3A has a porous surface 38 facing the extra-articular section and a nonporous surface 40 facing the intra-articular section. In this embodiment, the nonporous surface prevents tissue ingrowth at the intra-articular section. This is advantageous in certain operative contexts, such as total knee replacements, where tissue ingrowth could limit the range of motion of the prosthetic joint. In addition, unwanted tissue ingrowth could cause pain if pinched by the articulating surfaces of the prosthetic joint. In contrast to the membrane of Figure 3A, the membranes of Figures 3B and 3C are porous on both surfaces. The membrane of Figure 3B is formed as a composite, with nonporous material 42 interposed between porous surfaces 44, and the layered membrane of Figure 3C has two porous layers 46 and a nonporous layer 48 interposed between the two porous layers 46. These membranes provide twice the surface area for tissue ingrowth, which proves advantageous in operative contexts where increased stability is desirable, such as shoulder replacement with a capsular or rotator cuff tear, or revision hip arthroplasty.

Although Figures 1, 4, and 5 employ the embodiment shown in Figure 3A, any of the three embodiments may be used in the present invention. Figure 4 illustrates a disarticulated total knee prosthesis, generally indicated 50. A knee prosthesis conventionally includes three components: a tibial component 52, a femoral component 54, and a patellar component 56. The tibial component 52 has a plateau 60 which mounted to a metal base (not visible, as obscured by the first membrane 62) for bone fixation. Sometimes the plateau and base are one piece, made of polymeric material, and the one piece tibial component is cemented to bone. A stem 58 (also known as a peg or keel) may extend from the base of the plateau 60 for fixation within bone. The plateau 60, which is generally comprised of a polymeric material, articulates against the femoral component 54. The patellar component 56, which articulates or slides relative to an area of the femoral component 54 labeled 57, may have pegs 76 for bone fixation.

A first membrane 62 is attached to an outer periphery of the tibial component 52 at a position between the articulating surface of the plateau 60 and the surface of the base opposite the articulating surface, preferably closer to the base. A second membrane 64 is attached along the outer periphery of the femoral component 54. And, finally, a third membrane 68 is attached to an outer periphery of a base of the patellar component 56. The membranes , together, prevent migration of wear debris from the articulating surfaces 70a and 70b of the tibial component 52 and femoral component 54, respectively, to the implant/bone interface and prevent debris from migrating between the femoral component 54 and the patellar component 56. The membranes preferably have porous surfaces 72a, 72b, and 72c that face the extra-articular section of the prosthesis and nonporous surfaces 74a, 74b, and 74c that face the intra-articular section.

As evident from Figure 4, the outer peripheries of the membranes 62, 64, and 68 curve away from the articulating surfaces 70a and 70b of the prosthesis. Thus, the membranes do not catch between the surfaces as the knee joint moves. The membranes also extend out from the prosthesis to a width sufficient to cover the implant/bone interfaces.

Figure 5 illustrates a disarticulated total shoulder prosthesis, generally indicated 78, in accordance with the invention. The prosthesis 78 includes a humeral component 80 and a glenoid component 82. The humeral component 80 has a stem 84 for bone fixation and an intra-articular head 86. A first membrane 88 is attached to, and extends outward from, a location between the stem 84 and the intra-articular head 86. The glenoid component 82 includes a stem or keel 90 for bone fixation and an articulating surface 92. A second membrane 94 encircles and extends out from an outer periphery of a base of the glenoid component 82. The first and second membranes 88 and 94 both have porous surfaces 96a and 96b, respectively, that face the extra-articular section of the shoulder prosthesis and nonporous surfaces 98a and 98b, respectively, that face the intra-articular section.

When implanted, the outer peripheries of the membranes in each of the embodiments shown in Figures 1, 4, and 5 lie up against soft tissues, for example, muscles, joint capsule, and ligaments, surrounding the joint at the margin of the prosthesis. Although the membranes do not physically separate these tissues from the articulating surfaces of the prosthetic components, the tissues generally act as their own barrier to wear debris . It will be understood by those skilled in the art that the location of the membranes may be shifted from their illustrated positions to other positions on the prosthetic components where they still would serve as a barrier between the articulating surfaces of the joint and the implant/bone interface.

A method of manufacturing a prosthetic implant that prevents migration of wear debris to implant/bone interfaces in accordance with the invention includes providing first and second prosthetic components. A first membrane is affixed to, and extends out from, the first prosthetic component at the juncture of an intra- articular section and an extra-articular section and the first prosthetic component . A second membrane is affixed to, and extends out from, the second prosthetic component at the juncture of an intra-articular section and an extra-articular section of the second prosthetic component. The membranes operate to prevent migration of wear debris from the implant's intra-articular section to the extra-articular section. This method of manufacture is suitable for hip and shoulder prosthetic implants and other prosthetic joints having only two prosthetic components.

With knee prosthetic implants, the method further includes providing a third prosthetic component, and affixing a third membrane to that third prosthetic component. The third membrane is affixed at the juncture of the intra-articular and extra-articular sections of the third prosthetic component. The third membrane extends out from the third prosthetic component.

A method of implanting a prosthetic device that prevents migration of wear debris into implant/bone interfaces in accordance with the invention includes providing a first prosthetic component having a first membrane affixed thereto. The first membrane is impermeable to wear debris. A second prosthetic component having a second membrane affixed thereto is also provided. Like the first membrane, the second membrane is impermeable to wear debris. The first prosthetic component is implanted into a first bone so that the first membrane extends over an interface between the first prosthetic component and the first bone. The second prosthetic component is implanted into a second bone so that the second membrane extends over an interface between the second prosthetic component and the second bone. The first and second membranes prevent passage therethrough of wear debris generated by articulating surfaces of the first prosthetic component and the second prosthetic component. This method of implantation is suitable for hip and shoulder replacement surgery.

With knee replacement surgery, the method further comprises providing a third prosthetic component having a third membrane affixed thereto. The third prosthetic component is implanted into a third bone and slides relative to the second prosthetic component. Like the first two membranes, the third membrane is impermeable to wear debris . Although the above description assumes that the entire natural joint would need replaced, one of skill in the art will readily understand that the invention contemplates a situation where only half of or part of a shoulder joint, hip joint, knee joint, or other natural joint would need replaced. In such a situation, a hemiprosthesis could be implanted in the patient, while the healthy part of the natural joint is retained. The hemiprosthesis includes a membrane for preventing migration of wear debris from the intra-articular section to the extra-articular section of the joint.

Persons of skill in the art will recognize that the subject inventive membrane may be applied to other prosthetic joints and at other anatomical locations to prevent the migration of wear debris. In addition, other advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, and representative devices, shown and described herein. Various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims.

Claims

What Is Claimed Is:

1. A prosthetic joint apparatus for replacement of a damaged natural joint in a patient's body, the prosthetic joint apparatus comprising: a first prosthetic component for securing to a first bone ; a second prosthetic component for securing to a second bone, said first prosthetic component and said second prosthetic component having engaging, articulating surfaces to permit relative movement between the first bone and the second bone; a first membrane for attachment to said first prosthetic component, said first membrane having a porous surface facing an extra-articular section of said first prosthetic component and having a second surface facing an intra-articular section of said first prosthetic component ; and a second membrane for attachment to said second prosthetic component, said second membrane having a porous first surface facing an extra-articular section of said second prosthetic component and having a second surface facing an intra-articular section of said second prosthetic component, wherein said first membrane and said second membrane are impermeable to wear debris to prevent migration of wear debris from the intra-articular sections to the extra-articular sections of said first and second prosthetic components.

2. The apparatus as claimed in claim 1, wherein said porous first surface of each of said first membrane and said second membrane has a pore size of at least 20 microns .

3. The apparatus as claimed in claim 1, wherein said second surface of each of said first membrane and said second membrane is nonporous.

4. The apparatus as claimed in claim 1, wherein said second surface of each of said first membrane and said second membrane is porous, and a nonporous material is interposed between said first surf ce and said second surface .

5. The apparatus as claimed in claim 4, wherein said first membrane and said second membrane are composites .

6. The apparatus as claimed in claim 4, wherein said first membrane and said second membrane are layered, where a first layer includes said porous, first surface, a second layer includes said porous, second surface, and a third layer of said nonporous material is interposed between said first layer and said second layer.

7. The apparatus as claimed in claim 1, wherein at least one of said first membrane and said second membrane is toroidal in shape.

8. The apparatus as claimed in claim 1, wherein at least one of said first membrane and said second membrane is formed in a strip.

9. The apparatus as claimed in claim 1, wherein said first membrane and said second membrane each have an inner periphery attached to said respective prosthetic component and a curved, outer periphery extending away from the articulating surface of said respective prosthetic components.

10. The apparatus as claimed in claim 1, wherein said first membrane and said second membrane are composed of a biocompatible material selected from the group consisting of polytetrafluoroethylene and polyethylene terephthalate .

11. The apparatus as claimed in claim 1, wherein said first membrane and said second membrane have a width of about 1.0 to 2.0 cm.

12. The apparatus as claimed in claim 1, wherein said first membrane and said second membrane have a thickness of at least 0.5 mm.

13. The apparatus as claimed in claim 12 , wherein said thickness is about 0.5 to 2.0 mm.

14. The apparatus as claimed in claim 1, further comprising: a third prosthetic component; and a third membrane for attachment to said third prosthetic component, said third membrane having a porous surface facing the extra-articular section of said third prosthetic component, and said third membrane being impermeable to wear debris.

15. The apparatus as claimed in claim 1, wherein: the prosthetic joint is a hip prosthesis, said first prosthetic component is an acetabular component, and said second prosthetic component is a femoral component; said first membrane attaches to said femoral component at a location along a neck portion of said femoral component between a head portion and a stem portion of said femoral component; and said second membrane attaches around said acetabular component at one of an outer periphery of a liner of said acetabular component and, where present, an outer periphery of a base of said acetabular component, wherein said first membrane and said second membrane prevent migration of wear debris generated by articulating surfaces of said hip prosthesis into areas where said hip prosthesis interfaces with bone.

16. The apparatus as claimed in claim 1 wherein: said joint prosthetic is a shoulder prosthesis, said first prosthetic component is a humeral component, and said second prosthetic component is a glenoid component; said first membrane attaches to said humeral component at a location between a head portion of said humeral component and a stem portion of said humeral component ; and said second membrane attaches to said glenoid component at an outer periphery of a base of said glenoid component, wherein said first membrane and said second membrane prevent migration of wear debris generated by articulating surfaces of said shoulder prosthesis into areas where said shoulder prosthesis interfaces with bone .

17. The apparatus as claimed in claim 14, wherein: said joint prosthetic is a knee prosthesis, said first prosthetic component is a tibial component, said second prosthetic component is a femoral component, and said third prosthetic component is a patellar component; said first membrane attaches to an outer periphery of said tibial component; said second membrane attaches to an outer periphery of said femoral component ; and said third membrane attaches to an outer periphery of a base of said patellar component, wherein said first membrane, said second membrane, and said third membrane prevent migration of wear debris generated by articulating surfaces of said knee prosthesis into areas where said knee prosthesis interfaces with bone.

18. An attachment for use with a prosthetic component of a prosthetic device, said attachment comprising : a membrane having an inner periphery for attachment around the prosthetic component, an outer periphery for extending away from the prosthetic component, a porous region facing the extra-articular section for tissue ingrowth, and a nonporous region impermeable to wear debris generated by articulating surfaces of the prosthetic device.

19. The attachment as claimed in claim 18, wherein said porous region has a pore size of at least 20 microns .

20. The attachment as claimed in claim 18, wherein said porous region includes a first surface and a second surface of said membrane, and said nonporous region is interposed between said first surface and said second surface .

21. The attachment as claimed in claim 20, wherein said membrane is a composite.

22. The attachment as claimed in claim 18, wherein said membrane is layered, said porous region includes a first layer and a second layer, and said nonporous region includes a third layer interposed between said first layer and said second layer.

23. The attachment as claimed in claim 18, wherein said membrane has two opposing surfaces, said porous region comprises a first of said two opposing surfaces, and said nonporous region comprises a second of said two opposing surfaces.

24. The attachment as claimed in claim 18, wherein said membrane is toroidal in shape.

25. The attachment as claimed in claim 18, wherein said membrane is formed in a strip.

26. The attachment as claimed in claim 18, wherein said outer periphery is curved.

27. The attachment as claimed in claim 18, wherein said membrane is composed of a biocompatible material selected from the group consisting of polytetrafluoroethylene and polyethylene terephthalate .

28. The attachment as claimed in claim 18, wherein said membrane has a width of about 1.0 to 2.0 cm.

29. The attachment as claimed in claim 18, wherein said membrane has a thickness of at least 0.5 mm.

30. The apparatus as claimed in claim 29, wherein said thickness is about 0.5 to 2.0 mm.

31. A method of manufacturing a prosthetic that prevents migration of wear debris to implant/bone interfaces, comprising: providing first and second prosthetic components, each having an intra-articular section and an extra- articular section; affixing a first membrane to the first prosthetic component at the juncture of the intra-articular section and the extra-articular section of the first prosthetic component so that the first membrane extends out from the first prosthetic component, said first membrane having a porous portion for tissue ingrowth facing the extra-articular section and a nonporous portion for preventing migration of wear debris therethrough; and affixing a second membrane to the second prosthetic device at the juncture of the intra-articular section and the extra-articular section of the second prosthetic component so that the second membrane extends out from the second prosthetic component, said second membrane having a porous portion for tissue ingrowth facing the extra-articular section and a nonporous portion for preventing migration of wear debris therethrough.

32. A method as claimed in claim 31, further comprising: providing a third prosthetic component having an intra-articular section and an extra-articular section; and affixing a third membrane to the third prosthetic component at the juncture of the intra-articular section and the extra-articular section of the third prosthetic component so that the third membrane extends out from the third prosthetic component, said third membrane having a porous portion for tissue ingrowth facing the extra-articular section and a nonporous portion for preventing migration of wear debris therethrough.

33. A method of implanting a prosthetic device that prevents migration of wear debris into implant/bone interfaces, comprising: providing a first prosthetic component having a first membrane affixed thereto, the first membrane being impermeable to wear debris; providing a second prosthetic component having a second membrane affixed thereto, the second membrane being impermeable to wear debris; implanting into a first bone the first prosthetic component so that the first membrane extends over an interface between the first prosthetic component and the first bone; and implanting into a second bone the second prosthetic component so that the second membrane extends over an interface between the second prosthetic component and the second bone, the first membrane and the second membrane preventing passage therethrough of wear debris generated by articulating surfaces of the first prosthetic component and the second prosthetic component.

34. A method as claimed in claim 33, further comprising: providing a third prosthetic component having a third membrane affixed thereto, the third membrane being impermeable to wear debris; affixing the third prosthetic component onto the second prosthetic component so that the third membrane prevents migration of wear debris between the second component and the third component .

35. A prosthetic joint component for replacement of a damaged natural joint component in a patient' s body, the prosthetic joint component comprising: a prosthetic component secured to a first bone; and a membrane for attachment to said prosthetic component between an intra-articular section and an extra-articular section of said prosthetic component, said membrane having a porous surface facing the extra- articular section of said prosthetic component and having a second surface facing the intra-articular section of said prosthetic component, said membrane being impermeable to wear debris to prevent migration of wear debris from the intra-articular section to the extra- articular section of said prosthetic component .