Prosthesis for Partial and Total Joint Replacement

Abstract

A prosthetic joint is secured to the bones forming the original joint by utilizing strictly mechanical fasteners, for example, a threaded rod engaging a tapped intramedullary canal. Cross locking members may be provided. The need for bone cement is avoided. The prosthetic joint may be used to replace one end of one bone forming the joint, utilizing the naturally occurring end of the other bone. Alternatively, both bone ends may be replaced with prosthetic joint portions. The decision to replace one or both bone ends may be made mid-surgery. The prosthetic joint portions are secured together utilizing ligament reconstruction members made from portions of the patient's tendons or allograft tendons. A bearing forming the interface between the two joint portions is designed to wear in order to protect the remaining components from wear, and to be easily replaced in relatively simple future surgeries.

Claims

1. A prosthetic joint, comprising: a first joint component that is structured for attachment to a first bone, the first joint component defining a channel therein, the channel being dimensioned and configured to receive a viscoelastic ligament reconstruction member passing completely therethrough; and a second joint component that is structured for attachment to a second bone, the second joint component including a ligament retention member, the ligament retention member being secured to the second joint component in a manner that permits compressing a portion of a viscoelastic ligament reconstruction member between the ligament retention member and the second bone; whereby the viscoelastic ligament reconstruction member is retained therein.

2. The prosthetic joint according to claim 1, wherein the first joint component includes a spool, the channel for receiving the viscoelastic ligament reconstruction member being defined at least partially within the spool.

3. The prosthetic joint according to claim 1, wherein the second joint component includes at least one threaded fastener passing through a hole defined within the ligament retention member and threadedly engaging an internally threaded fastener receiver, whereby tightening the threaded fastener moves the ligament retention member closer to the second bone.

4. The prosthetic joint according to claim 1, wherein one of the first joint component and second joint component includes at least one cross locking assembly, the at least one cross locking assembly being structured to resist rotation of either the first joint component or second joint component with respect to a bone when the first joint component or second joint component is installed within the bone, the cross locking assembly being structured to secure the ligament retention member to the second joint component.

5. The prosthetic joint according to claim 4, wherein the cross locking assembly includes a threaded fastener, the threaded fastener passing through a hole defined within the ligament retention member and threadedly engaging an internally threaded fastener receiver, whereby tightening the threaded fastener moves the ligament retention member closer to the second bone.

6. The prosthetic joint according to claim 1, wherein: the first joint component includes a first intramedullary stem and a first connection portion, the first intramedullary stem being secured to the first connection portion; and the second joint component includes a second intramedullary stem and a second connection portion, the second intramedullary stem being removably secured to the second connection portion.

7. A prosthetic joint for use in repairing a joint formed from an intersection of a first bone and a second bone, the prosthetic joint comprising: a first joint component that is structured for attachment to a first bone, the first joint component defining a channel therein, the channel being dimensioned and configured to receive a viscoelastic ligament reconstruction member passing completely therethrough; and a ligament retention member, the ligament retention member being structured to be secured to the second bone in a manner that permits compressing a portion of a viscoelastic ligament reconstruction member between the ligament retention member and the second bone, whereby the viscoelastic ligament reconstruction member is retained therein.

8. The prosthetic joint according to claim 7, wherein the first joint component includes a spool, the channel for receiving the viscoelastic ligament reconstruction member being defined at least partially within the spool.

9. The prosthetic joint according to claim 7, further comprising at least one threaded fastener passing through a hole defined within the ligament retention member and threadedly engaging an internally threaded fastener receiver, whereby tightening the threaded fastener moves the ligament retention member closer to the second bone.

10. A prosthetic joint for use in repairing a joint formed from an intersection of a first bone and a second bone, the prosthetic joint comprising: a viscoelastic ligament reconstruction member; a first joint component that is structured for attachment to a first bone, the first joint component being structured to secure the viscoelastic ligament reconstruction member thereto; a ligament retention member, the ligament retention member being structured to be secured to the second bone in a manner that permits compressing a portion of the viscoelastic ligament reconstruction member between the ligament retention member and the second bone; whereby compressing a portion of the viscoelastic ligament reconstruction member between the ligament retention member and the second bone retains the viscoelastic ligament reconstruction member therein.

11. The prosthetic joint according to claim 10, wherein the first joint component includes a spool, the channel for receiving the viscoelastic ligament reconstruction member being defined at least partially within the spool.

12. The prosthetic joint according to claim 10, further comprising at least one threaded fastener passing through a hole defined within the ligament retention member and threadedly engaging an internally threaded fastener receiver, whereby tightening the threaded fastener moves the ligament retention member closer to the second bone.

13. The prosthetic joint according to claim 12, further comprising a second joint component that is structured for attachment to the second bone, the second joint component being structured to receive the threaded fastener, whereby the threaded fastener resists rotation of the second joint component with respect to the second bone when the second joint component is within the second bone.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0098] FIG. 1 is an isometric view of a prosthetic joint.

[0099] FIG. 2 is an isometric view of the hinge portion of a prosthetic joint.

[0100] FIG. 3 is a side view of the prosthetic joint.

[0101] FIG. 4 is a partially cutaway isometric view of a second prosthetic joint component, showing the second prosthetic joint component engaging a spool attached to a first prosthetic joint component.

[0102] FIG. 5 is an isometric view of a base for a connection portion of a second joint components for a prosthetic joint.

[0103] FIG. 6 is an isometric view of a bearing retaining bracket.

[0104] FIG. 7 is a cross-sectional side view of a broaching process for installation of a prosthetic joint component.

[0105] FIG. 8 is a cross-sectional side view of a drilling process for installation of a prosthetic joint component.

[0106] FIG. 9 is a cross-sectional side view of a tapping process for installation of a prosthetic joint component.

[0107] FIG. 10 is a cross-sectional side view of a prosthetic joint component being installed within a bone.

[0108] FIG. 11 is a cross-sectional side view of a spool for a prosthetic joint component being installed.

[0109] FIG. 12 is a cross-sectional front view of a broaching process for installation of a prosthetic joint component.

[0110] FIG. 13 is a cross-sectional front view of a drilling process for installation of a prosthetic joint component.

[0111] FIG. 14 is a cross-sectional front view of a tapping process for installation of a prosthetic joint component.

[0112] FIG. 15 is a cross-sectional front view of a prosthetic joint component being installed within a bone, showing the prosthetic joint component partially installed.

[0113] FIG. 16 is a cross-sectional front view of a prosthetic joint component being installed within a bone, showing the final position of the prosthetic joint component.

[0114] FIG. 17 is a cross-sectional side view showing the insertion of ligament reconstruction members through the first prosthetic joint component.

[0115] FIG. 18 is a cross-sectional side view showing the attachment of ligament reconstruction members to the second prosthetic joint component, as well as the installation of cross locking members.

[0116] FIG. 19 is a cross-sectional side view of a ligament reconstruction for a prosthetic joint.

[0117] FIG. 20 is a cross-sectional front view of a prosthetic joint after installation for a hemiarthroplasty.

[0118] FIG. 21 is a cross-sectional front view of a prosthetic joint after installation for a total arthroplasty.

[0119] FIG. 22 is an isometric view of a connection portion for a humeral component of a prosthetic joint.

[0120] FIG. 23 is an isometric view of a bearing for a prosthetic joint.

[0121] FIG. 24 is a side elevational view of the bearing of FIG. 23.

[0122] Like reference characters denote like elements throughout the drawings.

DETAILED DESCRIPTION

[0123] Referring to the drawings, an example of a prosthetic joint 10 is illustrated. As shown in FIG. 1, the illustrated example of the prosthetic joint 10 is a hinge joint, with the specific example illustrated being an elbow joint. The prosthetic joint 10 includes a first component 12, which in the illustrated example is a humeral component utilized for reconstruction of the distal end of a humerus. The prosthetic joint 10 further includes a second component 14, which in the illustrated example is an ulnar components for use in reconstructing the proximal end of an ulna.

[0124] The humeral component 12 includes an intramedullary stem 16 that is rotatably and removably secured to a connection portion 18. The intramedullary stem 16 is structured for uncemented, mechanical securing within the intramedullary canal of the humorous. The illustrated example of the intramedullary stem 16 includes a threaded portion 20 disposed at one end, that is structured to engage a portion of the intramedullary canal that has been tapped with corresponding threads as described in greater detail below. The opposite end of the intramedullary stem 16 includes a head 22, which in the illustrated example has a slightly larger diameter than the immediately adjacent portion of the intramedullary stem 16. The tip 24 of the head 22 includes actuator engaging structures 26 that are structured to engage a rotatable actuation school. For example, the actuator engaging structures 26 could be a slot for a slotted screwdriver, a cross shaped slot for a Phillips head screwdriver, a hexagon shaped hole for an Allen wrench, a star shaped hole for a Torx screwdriver, or any other conventional actuator engaging structure.

[0125] Referring to FIGS. 1-4 and 22, the connection portion 18 of the humeral component 12 in the illustrated example includes a yoke 28 having first and second legs 30, 32, respectively, extending therefrom. The yoke's base 34 defines a channel 36 therein. As shown in FIG. 3, the channel 36 includes a narrow portion 38 that is a suitable diameter to receive the majority of the intramedullary stem 16, but is too narrow to receive the head 22. The channel 36 further includes a wider portion 40 having a sufficient diameter to receive the head 22. The intramedullary stem 16 may therefore be placed within the channel 36, where it is free to rotate, but where the head 22 is prevented from passing into the narrow portion 38 of the channel 36. A hole 35 is defined within the connection portion 18 for securing a cross locking member 33, as described in more detail below.

[0126] The distal ends 42, 44 of the legs 30, 32, respectively are structured to removably secure a spool 46 therebetween. In the illustrated example, openings 48, 50 are defined within the distal ends 42, 44 of the legs 30, 32. The holes 48, 50 are each structured to receive a fastener such as the illustrated screws 52 (FIG. 7) passing therethrough and into corresponding threaded holes 53 defined within the spool 46. The spool 46 is generally cylindrical, and has a generally concave bearing surface 54 extending between its ends. The end 56 of the spool 46 corresponding to the leg 32 is generally flat, and the end 58 of the spool 46 corresponding to the leg 30 is partially spherical. The spool 46 therefore has a shape that generally corresponds to the shape of the distal end of an undamaged humerus. A central bore 53 passes through the spool 46, with corresponding holes 55, 57 being defined within the distal ends 42, 44 of the legs 30, 32, respectively.

[0127] Referring to FIGS. 20 and 22, the humeral portion 12 includes a cross locking member 33. In the illustrated example, the cross locking member 33 is a screw passing through a corresponding opening 35 defined within the connection portion 12. The screw 33 is secured at the opposite and of the hole 35 by a nut 37.

[0128] Referring to FIGS. 1-6, the ulnar component 14 includes in intramedullary stem 60 and a connection portion 62. The intramedullary stem 60 is structured for mechanical, cementless installation into the intramedullary canal of an ulna. In the illustrated example, the distal end 64 of the intramedullary stem 60 is threaded, so that it may engage corresponding threads that have been tapped into the ulna intramedullary canal. The proximal end of the intramedullary stem 60 includes a head 66, having a larger diameter than adjacent portions of the intramedullary stem 60. The tip 68 of the head 66 includes actuator engaging structures 70 that are structured to engage a rotatable actuation school. For example, the actuator engaging structures 70 could be a slot for a slotted screwdriver, a cross shaped slot for a Phillips head screwdriver, a hexagon shaped hole for an Allen wrench, a star shaped hole for a Torx screwdriver, or any other conventional actuator engaging structure.

[0129] The connection portion 62 includes a base 72. The base 72 defines a channel 74 therein. The channel 74 includes a narrow portion 76 that is structured to receive the intramedullary stem 60, but not the head 66. A wider portion 78 of the channel 74 is structured to receive the head 66. The intramedullary stem 60 may therefore be placed within the channel 74, and rotatably secured therein, in a manner that prevents the head from passing into the narrow portion 76. The illustrated example includes a threaded hole 80 which, in the illustrated example, is coaxial with the channel 74, and whose purpose will be explained below.

[0130] The connection portion 72 further includes a bearing retention structure 82. The bearing retention structure 82 includes a concave, generally circular interior surface 84. A bearing retaining flange 86 is disposed at one and of the interior surface 84. The other end of the interior surface 84 terminates adjacent to the threaded hole 80. Referring specifically to FIGS. 5-6, a pair of locating flanges 88, 90 are disposed on either side of the threaded hole 80. A bearing retaining bracket 92, which is best illustrated in FIG. 5, defines a generally circular surface 94 that is structured to form a continuation of the surface 84, and terminating in a bearing retaining flange 96. The opposite end of the bracket 92 defines a hole 98 therethrough, corresponding to the threaded hole 80. A pair of slots 100, 102 on either side of the hole 98 correspond to the locating flanges 88, 90, respectively, facilitating precise placement of the bracket 92 in the desired location. With the bracket in this position, a bearing 104 may be retained by the connection portion 14. A screw 106 passing through the hole 98 and engaging the threaded hole 80 secures the bearing retaining bracket 92 to the base 72.

[0131] Referring to FIGS. 1-4 and 23-24, the bearing 104 is generally half doughnut shaped, defining an interior, generally semicircular surface 108, and an exterior, generally semicircular surface 110. The bearing 104 preferably extends around at least about half of the spool 46, but defines a sufficient opening to allow for easy installation of the bearing 104 on the spool 46, for example, within a range of about 180° to about 270°. The bearing 104 in the illustrated example extends around about 236°. The interior surface 108 is generally convex, having a shape corresponding to the shape of the spool 46. The exterior surface 110 defines a channel 111 therein for receiving the bearing retention structure 82 as well as the bracket 92. The channel 111 is angled with respect to the circumference of the bearing 104 to accommodate the angle made by the bearing 104 with respect to the ulnar component 14, which in the illustrated example is about 7°. The retaining flanges 86, 96 are wider than the channel 111 so that the bearing 104 is properly retained. The bearing 104 is preferably made from a material having a wear resistance that is less than the wear resistance of the components with which it interfaces, so that the bearing 104 will experience wear in preference to other portions of the prosthetic joint. In the illustrated example, the bearing 104 is preferably made from polyethylene.

[0132] Referring to FIGS. 17-20, a cross locking assembly 114 for the ulnar component 14 is illustrated. The cross locking assembly 114 includes a plurality of cross locking members 116, which in the illustrated example are screws. The cross locking screws 116 pass through corresponding holes 118 (FIG. 4) defined it within the base 72, and are retained by corresponding nuts 120 disposed on the opposite sides of the holes 118. The screws 116 and nuts 120 also retain the bars 122, 124 in place against the base 72, for a purpose that will be described in greater detail below.

[0133] A method of installing the first joint component within the first bone (installing the humeral portion within the distal end of the humerus 126 in the illustrated example) is illustrated in FIGS. 7-11. This method remains the same regardless of whether a hemiarthroplasty or total arthroplasty is being performed. Initially, the damaged distal end of the humerus is cut with a saw. Next, as illustrated in FIG. 7, the intramedullary canal 128 is broached to remove marrow, as well as to provide adequate room for a drilling jig, as well as ultimately for the humeral implant 12. In some examples, three different sizes of brooches 130 may be utilized.

[0134] As shown in FIG. 8, a jig 132 is inserted into the intramedullary canal 128, and is used to guide a drill 134 in further clearing the marrow from the intramedullary canal 128. Successively larger drill bits are used until proprioceptive and or audible indications of drilling solid bone are heard. Once solid bone has been reached, the intramedullary canal 128 is tapped using a handheld tap 136, as shown in FIG. 9, thereby providing threads corresponding to the threads 20 of the intramedullary stem 16.

[0135] Referring to FIG. 10, an appropriately sized intramedullary stem 16 and connection portion 18 are selected. It is anticipated that different sizes of intramedullary stem 16 and connection portion 18 may be provided, thereby accommodating patients of different sizes. Because the intramedullary stem 16 is removably secured to the connection portion 18, the appropriate combination of parts may be selected. The intramedullary stems 16 is placed within the channel 36, and is then threaded until secured within the intramedullary canal utilizing an appropriate screwdriver 138 or other suitable hand tool. Because the intramedullary stem 16 is rotatable with respect to the connection portion 18, the connection portion 18 remains in the appropriate position for proper seating within the distal humerus 126 well-being drawn tightly into place by turning the intramedullary stem 16. During this operation, the spool 46 is detached from the connection portion 18 in order to facilitate access by the tool 138.

[0136] Once the connection portion 18 is firmly seated in place, as shown in FIG. 11, a hole corresponding to the hole 35 is drilled into the humerus 126, and the cross locking screw 33 is inserted into the hole 35. The nut 37 is added to complete the humeral cross locking structure. Next, the spool 46 is positioned between the legs 30, 32, and secured in place using the screws 52. At this point, the end is surface of the distal humerus 126 has been restored, and may be utilized for either a hemiarthroplasty utilizing an undamaged proximal ulna, or a total arthroplasty by installing an ulnar component as described below.

[0137] Referring to FIGS. 12-16, a method of installing the ulnar joint portion 14 is illustrated. Initially, the proximal end of the ulna 140 is broached utilizing a hand-held broach 142 to remove marrow from the intramedullary canal 144, as shown in FIG. 12. Next, a jig 146 is positioned within the proximal end of the intramedullary canal 144 to guide a drill 148 into the intramedullary canal 144 as shown in FIG. 13. Successively larger drill bits 148 are utilized until the marrow has been removed from a portion of the intramedullary canal to be tapped, and proprioceptive or audible indications that solid bone has been engaged are felt or heard. At this point, the intramedullary canal is tapped as shown in FIG. 14 by a handheld tap 150 to produce threads corresponding to the threads and 64 of the intramedullary stem 60. At this point, the ulna 140 is prepared for installation of the prosthetic joint portion 14.

[0138] An appropriately sized intramedullary stem 60 is paired with an appropriately sized base 72, as shown in FIG. 15. Different sized, interchangeable intramedullary stems 16 and bases 72 may be selected depending on the characteristics of the patient. The intramedullary stem 60 is placed within the channel 74, and the threads 64 are brought into engagement with the threads that were tapped into the intramedullary canal 144. An appropriate tool, which in the illustrated example is the screwdriver 152, is inserted into the threaded hole 80 and brought into engagement with the actuator engaging structures 70 within the head 66 of the intramedullary stem 60. The screwdriver 152 is turned to pull the prosthetic joint portion 114 into the ulna 140. Because the intramedullary stem 60 is rotatable with respect to the base 72, the base 72 may remain in a proper orientation as the intramedullary stem 60 is turned, thereby permitting the turning of the intramedullary stem 60 to draw the base 72 tightly into position within the ulna, as shown in FIG. 16.

[0139] Once the prosthetic joint component 14 has been installed within the ulna, a bearing 104 is placed against the interior surface 84 of the base 72 (FIGS. 4-6). The bearing retaining bracket 92 is positioned against the base 72. The screw 106 is then secured within the threaded hole 80, thereby securing the bracket 92 and bearing 104 in position within the prosthetic joint component 14. At this point, the prosthetic joint components 12, 14 are ready to be joined together. Also, at this time, holes are drilled in the ulna 140 to correspond to the holes 118 in the base 72.

[0140] Regardless of whether hemiarthroplasty or total arthroplasty is being performed, the illustrated example substantially mimics the movement and stability of a natural joint through a system of ligament reconstruction. Joint stability is defined as the resistance to subluxation under physiologic stress and is the result of the mechanical interaction of the articular contours, the dynamic support of the investing musclotendinous units, and the static viscoelastic constraint of the capsuloligatmentous structures. In order to be useful to the patient, the design of the prosthetic joint 10 must preserve this stability. Given that this design aims to replicate the native elbow bony anatomy and does not utilize a mechanical hinge to resist varus and valgus forces, the stability requirements are placed on the soft tissues.

[0141] Collateral ligaments are complex structures whose individual fascicles are under differential tension and whose properties depend on joint position and load. The collateral ligaments of the elbow, by virtue of their medial and lateral locations, have a mechanical advantage in resisting medially and laterally directed forces that would cause joint subluxation. In an effort to gain joint visualization during arthroplasty surgery, these ligaments are detached and then re-inserted once the implants have been placed. Reattachment is difficult to do particularly when the ligament integrity is compromised such as in the joints of elderly patients. Patients suffering from post-traumatic arthritis often sustained soft tissue as well as bony trauma making a subsequent collateral ligament repair more tenuous. Therefore, tendons taken from the patient or allograft tendons are utilized as ligament reconstruction members, as described below.

[0142] Initially, tendons are selected from the patient for use in reconstructing the ligaments. The specific tendon or tendon portion selected are chosen because its loss will have minimal or no impact on the patient. Tendons that may be advantageously utilized include a longitudinal strip of triceps tendon or the Palmaris Longus tendon. Alternatively, toe extensors or the Plantaris tendon or even half of the Flexor Carpi Radialis tendon can be used. Allograft tendon material may also be utilized.

[0143] With the appropriate ligament reconstruction members 154 obtained, the humeral joint portion 12 and ulna (in the case of hemiarthroplasty) or ulnar joint portion 14 (in the case of total arthroplasty) are placed against each other as shown in FIG. 17. The ulnar articulating surface will be native cartilage if a hemiarthroplasty is being performed, or the bearing 104 if total elbow arthroplasty is being performed. The ligament reconstruction members 154 are utilized to connect the humeral joint portion 12 and ulnar joint portion 14 by securing a portion of the ligament reconstruction members 154 to the humeral portion 12, and another portion of the ligament reconstruction members 154 to the ulnar portion 14. In the illustrated example, a central portion 156 of the ligament reconstruction members 154 is passed through the central bore 53 of the spool 46, as well as the holes 55, 57 defined within the distal ends 42, 44 of the legs 30, 32 of the yoke 28. The end portions 158 of the ligament reconstruction members 154 are then tensioned in order to remove their viscous properties, and secured to either the ulna (in the case of a hemiarthroplasty) or to the base 72 of the ulnar joint component 14 (in the case of a total arthroplasty) by securing the ends of the ligament reconstruction members 154 underneath the plates 122, 124. The plates 122, 124 in the illustrated example are held in place by the cross locking screws 116 and nuts 120, so cross locking of the ulnar component is also accomplished during this step. The tendon to bone fixation is, thereby, accomplished through the creation of compressive force exerted between the ulna and the plate. This method will maintain the appropriate tension within the tendons while bone to tendon healing occurs, and thereby ensures the stability of the reconstructed joint. This design also maintains the dynamic support of the extensor and flexor tendon insertions, which is accomplished by leaving the lateral and medial epicondyles intact.

[0144] The prosthetic joint described above provides numerous advantages over the prior art. The present design does not include cement fixation at all, and thereby eliminates the risk of bone cement implantation syndrome, as well as the other disadvantages of using bone cement. It is anticipated that, as the bones heal, they will grow into and/or around the various components of the prosthetic joint, thereby enhancing the security with which the prosthetic joint components are attached to the respective bones. Avoiding bone cement removes the exothermic curing process that may damage bone secondary to thermal osteonecrosis. In the event of infection, removal and replacement of prosthetic joint components is greatly simplified.

[0145] The attachment of the prosthetic joint components to the respective bones is particularly secure, and is anticipated to be able to withstand forces imparted to the biomechanical construct in excess of those which could be withstood by prior prosthetic joints. The use of relatively long intramedullary stems increases the surface area against which forces are applied, thereby reducing the pressure applied for an equivalent force. A screw that gains purchase in the threaded intra-medullary canal can pull the implant into the bone and create a very stable intra-medullary fixation based construct by distributing the forces over a sizeable number of threads. By leveraging the length of the humerus and ulna as well as the high cortical to cancellous bone ratio within the middle thirds of the humerus and ulna, the proposed method of fixation will make secure un-cemented implant fixation possible in a safe and reproducible manner. By distributing the forces over multiple threads, fixation through the intra-medullary screw is possible and reproducible even in bone that is fragile as is seen in osteoporotic patients. The use of interchangeable intramedullary stems and connection portions makes it possible to provide different length threaded rods that would not over-penetrate the far cortex beyond where it is achieving fixation. The use of cross locking members resists any tendency of the intramedullary stems to loosen over time.

[0146] The prior art method of constraining a total elbow arthroplasty resides in either using a hinge device in the implant (constrained) or repairing the ligaments after elbow replacement (unconstrained). No commercially available or previously marketed design attempts to provide stability through reconstruction of the elbow ligaments. Conversely, in the present design, the elbow is stabilized in a manner that most closely approximates how it functions in vivo. Secure ligament reconstruction is particularly advantageous as the patient populations that frequently receives this type of surgery often suffer from inflammatory arthritis and may not have a soft tissue envelope that can be relied on to provide stability when reattached after implantation. The use of autograft or allograft ligament reconstruction members provides a means of accommodating varus/valgus movement by transferring forces to the medial and lateral ligaments of the elbow similar to what is experienced in vivo.

[0147] The prosthetic joint described above further provides for simplified surgery. The surgeon need not decide between hemi arthroplasty and total arthroplasty prior to performing the surgery, and can instead make this intraoperative decision. An easily replaced bearing is designed to wear in preference to components that are more difficult to replace. When the bearing wears out, which is anticipated to be a period of years, a relatively simple surgery may be used to replace the bearing.

[0148] A variety of modifications to the above-described embodiments will be apparent to those skilled in the art from this disclosure. For example, other methods of attaching ligament reconstruction methods between the respective joint components could be utilized without departing from the scope of the invention. Additionally, other hinge joints, such as knees, fingers, etc., may be repaired using a prosthetic joint described herein. Additionally, a ball and socket joint such as a shoulder or hip would equally benefit from the cementless attachment methods taught herein, as well as variations of ligament reconstruction utilizing tendons from the patient to secure the mating joint components. Thus, the invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The particular embodiments disclosed are meant to be illustrative only and not limiting as to the scope of the invention. The appended claims, rather than to the foregoing specification, should be referenced to indicate the scope of the invention.