Abstract:
A mobile bearing knee prosthesis enables a surgeon to convert a mobile bearing insert having articular surfaces, supported by a tibial base plate or tray from a rotating and translating prosthesis to one that rotates only. This conversion is accomplished with a fastener or locking member that connects through an opening in the insert to the tibial base plate. This prosthesis can be used as part of a total knee surgery when the surgeon chooses to use a prosthesis that incorporates a movable articular surface. In one embodiment, a projecting portion extends proximally from the insert and cooperates with a cam on the femoral component. The projecting portion can be a post extending up from the proximal surface of the insert and the femoral component includes an intercondylar surface that may contact the post to constrain the relative motion between the femoral component and the insert. In another embodiment, the insert is a two part assembly that includes a larger member with a central opening and a smaller member that fits the opening.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation-in-part of U.S. patent application Ser. No. 09/082,179, filed May 20, 1998, now U.S. Pat. No. 6,123,728 which is incorporated herein by reference. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     REFERENCE TO A “MICROFICHE APPENDIX” 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to orthopaedic prosthetic devices, and more particularly to an improved rotating platform, mobile knee prosthesis that incorporates anterior stabilization along with the ability to constrain the movement of the articular surface from rotation and translation, to rotation only. 
     2. General Background of the Invention 
     Femoral rollback is believed to improve range of motion and extensor mechanism leverage so as to improve efficiency and more accurately replicate natural kinematics. Conventional mobile bearing designs may lack the desired effect of femoral rollback, particularly in the absence of the posterior cruciate ligament. 
     Posterior Stabilized (PS) fixed bearing designs provide femoral rollback by articulating a cam on the femoral component with a post on the tibial articular insert during flexion. However, PS fixed bearing designs do not have the advantages of mobile bearing designs with regards to enhanced range of motion, reduced rehabilitation time, improved patellofemoral alignment, increased contact area, and reduced bone-implant interface shear forces. 
     In fixed bearing designs, excessive wear of the PS post can occur during articulation with the femoral cam. Internal-external rotation of the femoral component reduces the PS post-femoral cam congruency which increases contact stresses. The increased contact stresses can lead to excessive polyethylene wear and component failure. Allowing the PS post to rotate within a fixed articular insert will maintain femoral cam-PS post congruency during internal/external rotation of the femoral component. 
     Further, in any type of posterior stabilized design (fixed bearing or mobile bearing), one of the most problematic failure modes of the polyethylene is the fracture of the central post of the insert. This failure can be attributed to “notching” the anterior side of the central post with the anterior most inner-condylar area of the femoral component. Thus, any mechanism to reduce the probability for impingement of the femoral component against the anterior side of the tibial central post in hyper-extension would reduce the probability for tibial insert post failure due to “notching” and ultimately breaking. 
     Previous rotating platform designs have incorporated rotating only, or rotation and translation through the use of different prostheses. An example of a prosthesis that rotates and translates is shown in British publication 2219942, entitled “Knee Prosthesis”. U.S. Pat. No. 5,906,643 provides a tibial baseplate with a post that protrudes through a meniscal component and articulates with a cam on a femoral component. The post is an integral part of the tibial baseplate. 
     U.S. Pat. No. 5,879,392 provides a tibial baseplate with a fixed post that extrudes through the stem of the tibial baseplate and through the bearing component and articulates with a recess within the femoral component. 
     EP 0 916 321 A2 provides a femoral component with transverse flanges on the medial and lateral surfaces of the posterior stabilized box that articulate with projections from the medial and lateral surfaces of the post. 
     WO 95/35484 provides a bearing component with a post that articulates with a recess within the femoral component. The bearing component is limited in rotational, anterior, and posterior movement with respect to the tibial component. 
     The following patents relate to other orthopedic prosthetic devices, many of the listed patents pertaining to a knee prosthesis: 
     
       
         
               
               
               
             
           
               
                   
               
               
                 Patent # 
                 Issue Date 
                 Title 
               
               
                   
               
             
             
               
                 3,899,796 
                 08/19/75 
                 Metacarpophalangeal Joint 
               
               
                 4,016,606 
                 04/12/77 
                 Knee Joint Prosthesis 
               
               
                 4,094,017 
                 06/13/78 
                 Knee Joint Prosthesis With Patellar-Femoral 
               
               
                   
                   
                 Contact 
               
               
                 4,216,549 
                 08/12/80 
                 Semi-Stable Total Knee Prosthesis 
               
               
                 4,224,697 
                 09/30/80 
                 Constrained Prosthetic Knee 
               
               
                 4,257,129 
                 03/24/81 
                 Prosthetic Knee Joint Tibial Implant 
               
               
                 4,340,978 
                 07/27/82 
                 New Jersey Meniscal Bearing Knee Replacement 
               
               
                 4,673,407 
                 06/16/87 
                 Joint-Replacement Prosthetic Device 
               
               
                 4,822,366 
                 04/18/89 
                 Modular Knee Prosthesis 
               
               
                 4,936,853 
                 06/26/90 
                 Modular Knee Prosthesis 
               
               
                 4,950,297 
                 08/21/90 
                 Knee Prosthesis 
               
               
                 4,959,071 
                 09/25/90 
                 Partially Stabilized Knee Prosthesis 
               
               
                 5,007,933 
                 04/16/91 
                 Modular Knee Prosthesis System 
               
               
                 5,032,132 
                 07/16/91 
                 Glenoid Component 
               
               
                 5,071,438 
                 12/10/91 
                 Tibial Prosthesis With Pivoting Articulating 
               
               
                   
                   
                 Surface 
               
               
                 5,116,375 
                 05/26/92 
                 Knee Prosthesis 
               
               
                 5,271,747 
                 12/21/93 
                 Meniscus Platform for an Artificial Knee Joint 
               
               
                 5,282,868 
                 02/01/94 
                 Prosthetic Arrangement for a Complex Joint, 
               
               
                   
                   
                 Especially Knee Joint 
               
               
                 5,314,483 
                 05/24/94 
                 Meniscus Platform for an Artificial Knee Joint 
               
               
                 5,344,460 
                 09/06/94 
                 Prosthesis System 
               
               
                 5,370,699 
                 12/06/94 
                 Modular Knee Joint Prosthesis 
               
               
                 5,387,240 
                 02/07/95 
                 Floating Bearing Prosthetic Knee 
               
               
                 5,395,401 
                 03/07/95 
                 Prosthetic Device for a Complex Joint 
               
               
                 5,404,398 
                 04/11/95 
                 Prosthetic Knee With Posterior Stabilized 
               
               
                   
                   
                 Femoral Component 
               
               
                 5,413,604 
                 05/09/95 
                 Prosthetic Knee Implant for an Anterior Cruciate 
               
               
                   
                   
                 Ligament Deficient Total Knee Replacement 
               
               
                 5,413,608 
                 05/09/95 
                 Knee Joint Endoprosthesis for Replacing the 
               
               
                   
                   
                 Articular Surfaces of the Tibia 
               
               
                 5,549,686 
                 08/27/96 
                 Knee Prosthesis Having a Tapered Cam 
               
               
                 5,609,639 
                 03/11/97 
                 Prosthesis for Knee Replacement 
               
               
                 5,658,342 
                 08/19/97 
                 Stabilized Prosthetic Knee 
               
               
                 5,702,466 
                 12/30/97 
                 Rotational and Translational Bearing Combination 
               
               
                   
                   
                 in Biological Joint Replacement 
               
               
                 5,782,925 
                 07/21/98 
                 Knee Implant Rotational Alignment Apparatus 
               
               
                 5,871,543 
                 02/16/99 
                 Tibial Prosthesis With Mobile Bearing Member 
               
               
                 5,871,545 
                 02/16/99 
                 Prosthetic Knee Joint Device 
               
               
                 5,935,173 
                 08/10/99 
                 Knee Prosthesis 
               
               
                   
               
             
          
         
       
     
     GENERAL DISCUSSION OF THE PRESENT INVENTION 
     The present invention has as an object a tibial prosthesis and mating articular insert with specially configured stabilization posts. The invention enables for the surgeon to convert a mobile bearing articular surface from a fixed to a rotating only or translating only. The prosthesis can also provide both rotation and translation simultaneously. 
     These conversions are accomplished with special locking members or plugs that connect to the tibial base special plate. The plugs can be secured to the base plate with a taper lock or a threaded connection for example. 
     A post on the proximal tibial base plate can be positioned with an offset with respect to an oval hole in the articular insert to provide anterior stabilization in the total knee prosthesis. 
     The prosthesis of the present invention will be used as part of a total knee surgery when the surgeon chooses to use a prosthesis that incorporates a particular, selected relative motion between tibial tray and tibial insert. 
     This present invention consists of a posterior stabilized “PS” post which is secured to the mobile bearing tibial baseplate allowing only rotational movement. The PS post captures a bearing component to the tibial baseplate through an elongated slot in the bearing component. The elongated slot in the bearing component allows it to translate anteriorly and posteriorly with respect to the posterior stabilized post. The bearing component may also rotate with respect to the tibial baseplate in conjunction with the PS post. The bearing component has two concave surfaces that are articulate with the convex surfaces of the femoral component, and that are roughly congruent with the convex surfaces of the femoral component at zero degrees of flexion or full extension. The PS post articulates with a recess or cam of the femoral component to provide femoral rollback. 
     In addition to the above described design, the PS post should allow for posterior translation, in addition to rotational movement. This posterior movement would allow the post to translate instead of impinging upon the inner-condylar notch area of the femoral component in hyper-extension. 
     The PS post has a flat distal surface that articulates with the tibial baseplate. A T-slot is located on the distal end and articulates with a T-post on the tibial baseplate. A through hole in the PS post is located such that a rotation peg can capture the PS post to the tibial baseplate while the T-slot of the PS post is engaged with the T-post of the tibial baseplate. The rotation peg allows only rotational freedom of the PS post with respect to the tibial baseplate. The PS post has a flange on the medial and lateral surfaces that capture the bearing component through a counterbore on the medial and lateral sides of an elongated slot of the bearing component. The elongated slot of the bearing component is larger than the PS post in the anterior-posterior direction such that the bearing component has limited translation with respect to the PS post. The bearing component may also rotate with respect to the tibial baseplate in conjunction with the PS post. The bearing component has two concave surfaces that are congruent to the convex surfaces of the femoral component. A cam mechanism on the femoral component can be a concave cylinder that can be congruent to the convex posterior surface of the PS post. The internal/external rotation of the PS post with the femoral component can maintain this congruency throughout the range of motion unlike designs with a fixed PS post. 
     The addition of the posterior translation can occur with an anterior to posterior “A/P” slot instead of a hole as seen in the inferior view above. This slot would allow for posterior translation of the post relative to the insert/baseplate. 
     The “PS” post may engage the tibial baseplate through a pin means or through a boss of a configuration other than a T-post. The “PS” post may secure the bearing component through the use of slots or other means of capture. The “PS” post may articulate with a closed recess within the femoral component rather than a cam mechanism. 
     With the fixed bearing design, the means of “PS” post capture may be with the use of a retaining ring or a cross pin. The PS post may not require capture with the fixed bearing articular insert. 
     The present invention also provides an improved knee prosthesis apparatus that includes a tibial prosthesis that is configured to be surgically implanted on a patient&#39;s transversely cut proximal tibia and a femoral component. The femoral component articulate with a tibial insert having a proximal surface that engages the femoral component, the insert having a distal surface that fits against and articulates with the proximal surface of the tibial prosthesis. 
     A constraining mechanism joins the tibial insert to the tibial prosthesis in a selective fashion that enables a number of different possible relative motions between the insert and the tibial prosthesis, including anterior to posterior translation with rotation, or rotation only. 
     All or part of the constraining mechanism is separable from the tibial prosthesis, and selective removal of all or part of the constraining mechanism determines which of the said possible relative motions will take place. 
     The tibial prosthesis can have a fixator for holding the tibial prosthesis on a patient&#39;s proximal tibia such as for example, a stem, spike, cement, etc. 
     The proximal surface of the insert can have one or more concavities for articulating with the femoral component. 
     The femoral component can include an intercondylar surface that is positioned to contact the post, enabling relative motion between the femoral component and the insert to be constrained. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEW OF THE DRAWINGS 
     For a further understanding of the nature, objects, and advantages of the present invention, reference should be had to the following detailed description, read in conjunction with the following drawings, wherein like reference numerals denote like elements and wherein: 
     FIG. 1 is a perspective, exploded view of the preferred embodiment of the apparatus of the present invention; 
     FIG. 2 is a partial sectional of the preferred embodiment of the apparatus of the present invention illustrating the locking member portion thereof; 
     FIG. 3 is a top, fragmentary view of the preferred embodiment of the apparatus of the present invention illustrating the locking member portion thereof; 
     FIG. 4 is a partial, elevational view of the preferred embodiment of the apparatus of the present invention illustrating the locking member portion thereof; 
     FIG. 5 is a rear, elevational and exploded view of the preferred embodiment of the apparatus of the present invention illustrating the articular polymeric insert and tray portions thereof; 
     FIG. 6 is a sectional, elevational view of the preferred embodiment of the apparatus of the present invention shown with the locking member removed; 
     FIG. 7 is another sectional, elevational view of the preferred embodiment of the apparatus of the present invention illustrating the locking member in operating position when only rotational movement is desired; 
     FIG. 8 is a partial top view of the preferred embodiment of the apparatus of the present invention showing the polymeric insert; 
     FIG. 9 is a partial, bottom view of the preferred embodiment of the apparatus of the present invention showing the polymeric insert; 
     FIG. 10 is a partial rear view of the preferred embodiment of the apparatus of the present invention showing the polymeric insert; 
     FIG. 11 is a partial sectional view of the preferred embodiment of the apparatus of the present invention taken along lines  11 — 11  of FIG. 8; 
     FIG. 12 is a sectional view of the preferred embodiment of the apparatus of the present invention taken along lines  12 — 12  of FIG. 8; 
     FIG. 13 is a partial top view of the preferred embodiment of the apparatus of the present invention illustrating the tray or baseplate; 
     FIG. 14 is a sectional view of the preferred embodiment of the apparatus of the present invention taken along lines  14 — 14  of FIG. 13; 
     FIG. 15 is a top view of the preferred embodiment of the apparatus of the present invention illustrating the insert and tray portions thereof in operating position without the locking member; 
     FIG. 16 is a top side view of the preferred embodiment of the apparatus of the present invention illustrating the insert, tray and locking member portions thereof in operating position; 
     FIG. 17 is a top view of the preferred embodiment of the apparatus of the present invention illustrating rotation of the insert relative to the tray; 
     FIGS. 18-21 are fragmentary perspective views of an alternate embodiment of the apparatus of the present invention illustrating constructions for the post portion and illustrating the connection between the post and the tray; 
     FIGS. 22-25 are schematic plan views of alternate constructions of the tibial insert to be used respectively with the post constructions of FIGS. 18-21; 
     FIG. 26 is a top view of the second alternate embodiment of the apparatus of the present invention illustrating the tray portion thereof; 
     FIG. 27 is an elevational view of the second alternate embodiment of the apparatus of the present invention illustrating the tray portion thereof; 
     FIG. 28 is a bottom view of the second alternate embodiment of the apparatus of the present invention illustrating the tray portion thereof; 
     FIG. 29 is a plan view of the second embodiment of the apparatus of the present invention illustrating the polymeric insert portion thereof; 
     FIG. 30 is a frontal elevational view of the second alternate embodiment of the apparatus of the present invention illustrating the plastic insert portion thereof; 
     FIG. 31 is a bottom view of the plastic insert portion of the second alternate embodiment of the apparatus of the present invention; 
     FIG. 32 is a fragmentary view of the second alternate embodiment illustrating the locking plug member portion thereof; 
     FIG. 33 is a sectional view taken along lines  33 — 33  of FIG. 32; 
     FIG. 34 is a sectional view taken along lines  34 — 34  of FIG. 26 
     FIG. 35 is a sectional view taken along lines  35 — 35  of FIG. 29; 
     FIG. 36 is a sectional view taken along lines  36 — 36  of FIG. 29; 
     FIG. 37 is an elevational view of the second alternate embodiment of the apparatus of the present invention illustrating the cap and set screw separated from the insert and tray portions thereof; 
     FIG. 38 is a partial sectional elevational view of the second alternate embodiment of the apparatus of the present invention illustrating the mobile insert moving with respect to the tray; 
     FIG. 39 is a perspective exploded view of a third alternate embodiment of the apparatus of the present invention; 
     FIG. 40 is a partial top view of the third alternate embodiment of the apparatus of the present invention illustrating the insert portion thereof; 
     FIG. 41 is a side view of the insert portion of the third alternate embodiment of the apparatus of the present invention; 
     FIG. 42 is a perspective view of the insert portion of the third alternate embodiment of the apparatus of the present invention; 
     FIG. 43 is a posterior view of the insert portion of the third alternate embodiment of the apparatus of the present invention; 
     FIG. 44 is a bottom view of the tray portion of the third alternate embodiment of the apparatus of the present invention; 
     FIG. 45 is a side view of the tray portion of the third alternate embodiment of the apparatus of the present invention; 
     FIG. 46 is a perspective view of the tray portion of the third alternate embodiment of the apparatus of the present invention; 
     FIG. 47 is a posterior view of the tray portion of the third alternate embodiment of the apparatus of the present invention; 
     FIGS. 48-49 are fragmentary views of the third alternate embodiment of the apparatus of the present invention illustrating one of the plug portions thereof; and 
     FIGS. 50-51 are side and top views of a second plug portion that is used with the third alternate embodiment of the apparatus of the present invention; 
     FIG. 52 is a perspective, exploded view of a fourth alternative embodiment of the apparatus of the present invention; 
     FIG. 53 is a sectional, elevational view of the fourth alternative embodiment shown in FIG. 52, shown with the locking member removed; 
     FIG. 54 is another sectional, elevational view of the fourth alternative embodiment shown in FIG. 52, illustrating the locking member in operating position when only rotational movement is desired; 
     FIG. 55 is a partial top view of the fourth alternative embodiment of the apparatus shown in FIG. 52 illustrating the tray; 
     FIG. 56 is a sectional view of the fourth alternative embodiment of the apparatus shown in FIG. 52 taken along lines  56 — 56  of FIG. 55; 
     FIG. 57 is a perspective view of a fifth alternate embodiment of the apparatus of the present invention; 
     FIG. 58 is a side, elevation view of the fifth alternate embodiment of the apparatus of the present invention; 
     FIG. 59 is a posterior elevation view of a fifth alternate embodiment of the apparatus of the present invention; 
     FIG. 60 is a side elevation view of the fifth alternate embodiment of the apparatus of the present invention showing the knee in an extended position; 
     FIG. 61 is a side elevation view of the fifth alternate embodiment of the apparatus of the present invention showing the knee in a flexed position; 
     FIG. 62 is a fragmentary anterior elevation view of the fifth alternate embodiment of the apparatus of the present invention showing the polymeric insert; 
     FIG. 63 is a fragmentary posterior elevation view of the fifth alternate embodiment of the apparatus of the present invention showing the polymeric insert; 
     FIG. 64 is a fragmentary side sectional elevation view of the fifth alternate embodiment of the apparatus of the present invention showing the polymeric insert; 
     FIG. 65 is a fragmentary plan view of the fifth alternate embodiment of the apparatus of the present invention showing the polymeric insert; 
     FIG. 66 is a fragmentary bottom view of the fifth alternate embodiment of the apparatus of the present invention showing the polymeric insert; 
     FIG. 67 is a fragmentary perspective view of the fifth alternate embodiment of the apparatus of the present invention showing the polymeric insert; 
     FIG. 68 is a top view of the fifth alternate embodiment of the apparatus of the present invention; 
     FIG. 69 is a top view of a sixth alternate embodiment of the apparatus of the present invention; 
     FIG. 70 is a fragmentary bottom view of the sixth alternate embodiment of the apparatus of the present invention showing one of the polymeric insert portions; 
     FIG. 71 is a fragmentary top view of the sixth alternate embodiment of the apparatus of the present invention showing one of the polymeric insert portions; 
     FIG. 72 is a fragmentary, frontal, elevation view of the sixth alternate embodiment of the apparatus of the present invention showing one of the polymeric insert portions; 
     FIG. 73 is a fragmentary rear elevation view of the sixth alternate embodiment of the apparatus of the present invention showing one of the polymeric insert portions; 
     FIG. 74 is a fragmentary side sectional elevation view of the sixth alternate embodiment of the apparatus of the present invention showing one of the polymeric insert portions; 
     FIG. 75 is a fragmentary perspective view of the sixth alternate embodiment of the apparatus of the present invention showing one of the polymeric insert portions; 
     FIG. 76 is a side elevation view of the sixth alternate embodiment of the apparatus of the present invention illustrating one of the polymeric insert portions; 
     FIG. 77 is a fragmentary rear elevation view of the sixth alternate embodiment of the apparatus of the present invention illustrating one of the polymeric insert portions; 
     FIG. 78 is a fragmentary bottom view of the sixth alternate embodiment of the apparatus of the present invention illustrating one of the polymeric insert portions; 
     FIG. 79 is a fragmentary, frontal elevation view of the sixth alternate embodiment of the apparatus of the present invention illustrating one of the polymeric insert portions; 
     FIG. 80 is a fragmentary, plan view of the sixth alternate embodiment of the apparatus of the present invention illustrating one of the polymeric insert portions; and 
     FIG. 81 is a fragmentary, perspective view of the sixth alternate embodiment of the apparatus of the present invention illustrating one of the polymeric insert portions. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIGS. 1-7 show generally the preferred embodiment of the apparatus of the present invention designated generally by the numeral  10  in FIGS. 1,  6 , and  7 . 
     Mobile bearing knee prosthesis  10  is placed upon a patient&#39;s surgically cut proximal tibia  11  at a surgically cut proximal surface  12  that is preferably flat. This enables a tray  13  to be mounted to the proximal tibia  11  at surface  12  as shown in FIGS. 6 and 7. Tray  13  has a flat proximal surface  14  and a generally flat distal surface  15  that mates with and faces the surgically prepared surface  12  as shown in FIGS. 6-7. The tray  13  can provide a plurality of spikes  16  and a stem  17  for enhancing implantation to the patient&#39;s proximal tibia  11 . However, any other known attachment can be used to affix tray  13  to a patient&#39;s proximal tibia such as chemical (eg. element) or mechanical fasteners (or fastener). 
     The proximal surface  14  of tray  13  provides a post  18  having an internally threaded socket  19 . Post  18  is comprised of a generally cylindrically-shaped smaller diameter section  20  and an enlarged flange  21  that mounts to the top of cylindrically-shaped  20  as shown in FIGS.  5  and  13 - 14 . Tray  13  has a periphery  22 . A recess  23  is provided in between the proximal surface  14  of tray  13  and flange  21 . 
     A locking member  24  forms a removable connection with the socket  19 . Locking member  24  has an externally cylindrical section  25  that provides threads that correspond to the threads of internally threaded socket  19  so that the locking member  24  can be threaded into the socket  19  as shown in FIG.  7 . Locking member  24  includes an enlarged cylindrically-shaped head  26  having a tool receptive socket  27  such as a hexagonal socket for example. 
     An insert  28  provides a vertical channel  33  that can be placed in communication with post  18  as shown in FIGS. 6 and 7. Insert  28  provides a preferably flat distal surface  29  that communicates with the flat proximal surface  14  of tray  13 . A pair of spaced apart concavities  30 ,  31  are provided for defining articulation surfaces that cooperate with correspondingly shaped articulating surface on a patient&#39;s femur or femoral implant. The insert  28  has a periphery  32  that generally corresponds in shape to the periphery  22  of tray  13 . Insert  28  can be polymeric or metallic or of a composite construction, such as metallic with a polymeric articulating surface(s) or polymeric with a metallic articulation surface(s). 
     Vertical channel  33  is comprised of a number of sections that are specially shaped to interact with the post  18  and locking member  24 . Vertical channel  33  thus includes a proximal, cylindrically-shaped section  34 , an oval shaped slot  35 , and a distal opening  36 . The distal opening  36  includes a generally oval section  37  and a somewhat half oval section  38 . The oval section  38  can track any of three directions including a pure anterior to posterior direction, a direction that is at an angle to a pure anterior to posterior direction; or a direction that is an arcuate or curved path that pivots or rates about a point that is not located along the A/P centerline of the insert. Flat surfaces  39 ,  40  are positioned at the top of and at the bottom of the oval shaped slot  35  as best seen in FIGS. 8-11. The cylindrically-shaped head  26  of locking member  24  closely fits the cylindrically-shaped section  36 . 
     In order to assemble insert  28  to tray  13 , the distal surface of  29  of insert  28  is placed next to and generally parallel to the proximal surface  14  of tray  13 . Post  18  is aligned with vertical channel  33  of insert  28 . During assembly of insert  28  to tray  13 , the post  18  is shaped to enter the oval opening portion  37  of distal opening  36 . Once the distal surface  29  of insert  28  meets proximal surface  14  of tray  13 , flange  21  aligns with oval shaped slot  35  of vertical channel  33 . After such assembly, insert  28  is held in position by post  18 . This retention of insert  28  by post  18  occurs when flange  21  engages flat surface  40  to prevent separation if any rotation (see arrow  41  of FIG. 17) at all occurs between insert  28  and tray  13 . If no rotation has occurred between insert  28  and tray  13  (see FIG.  15 ), the oval shaped circular section  37  is sized to allow post  18  to be inserted into or withdrawn from channel  33 . 
     In FIG. 15, the apparatus  10  is shown in an assembled position wherein the fastener  24  has been removed so that the insert  28  can move in a translation and rotation and rotation fashion relative to tray  13 . In FIG. 16, the fastener  24  has been threadably attached to the internally threaded socket  19  and is in operating position. In FIG. 17, the insert  28  can rotate relative to the tray  13  through an angle  41 . However, because of the attachment of fastener  24 , only rotation and not translation is permitted in FIG.  17 . Thus, in FIG. 17, the apparatus  10  of the present invention provides a mating mechanism between the post  18  and the fastener  24  and the insert  28  that defines a constraining mechanism so that the insert  28  may be constrained for rotation only relative to the tray  13 . 
     In FIGS. 18-21 and  22 - 25 , there is seen various alternate constructions of the post that can be used instead of post  18  when the selected post is fitted to the tibial tray  13 . In FIGS. 22-25, an alternate construction of the insert  28  is shown with an illustration of the various types of relative motion between the insert and the tibial tray that can be selectively provided to a surgeon. 
     In FIG. 18-21, four different constructions of the post are provided. In FIG. 18, a post  42  has a cylindrical outer surface  43  and a circular top  44 . Post  42  has a rectangular base  45  with a generally flat undersurface and a plurality of four inclined surfaces  46  which provides a means of attaching the post to the tray or the post may be permanently attached to the tray. The rectangular base  45  fits tray  13 A socket  47  at its inclined surfaces  48  with a taper lock type connection for example. Other types of connections could be used to join post  42  to tray  13 A at socket  47 . 
     In FIG. 19, post  49  includes a plurality of four vertical side walls  50  and a plurality of four inclined surfaces  51 . A rectangular flat top  52  is provided opposite a generally flat undersurface of post  49 . The inclined surfaces  51  of post  49  fit similarly configured inclined surfaces  48  of socket  47  in tray  13 A. 
     In FIG. 20, post  53  is generally rectangularly shaped providing a pair of opposed flat larger vertical side walls  54  and a pair of opposed flat smaller end walls  55  with a flat top  56 . Post  53  has a base  57  that includes four inclined surfaces  58 . The inclined surfaces  58  form a taper lock connection with four similarly configured inclined surfaces  48  of socket  47  of tray  13 A. 
     In FIG. 21, post  59  has a hexagonal shape providing a hexagonally shaped flat top  60 . Hexagonal post  59  also has a plurality of vertical side walls  61  and a rectangular base  62 . The base  62  has inclined surfaces  63  that form a taper lock connection with inclined surfaces  48  of tray socket  47  of tray  13 A. 
     In FIG. 22, insert  28 A provides a square opening  64  that exactly fits peg  49 . In FIG. 22, there is no relative motion between insert  28 A and tray  13 A. In FIG. 23, rotational motion only is indicated by arrow  65  between insert  28 A and tray  13 A when peg  42  is used. 
     In FIG. 24, the rectangular peg  53  enables only translational movement between the insert  28 A and tray  13 A as indicated by arrow  66 . In FIG. 25, the hexagonal peg  59  enables both rotational motion as indicated by arrow  65  and translational motion as indicated by arrow  66  between insert  28 A and tray  13 A. 
     An alternate embodiment of mobile bearing knee apparatus  110  is shown generally in FIG.  37 . In FIG. 37, the prosthesis  110  is shown positioned upon a patient&#39;s proximal tibia  111 , specifically upon a flat surgically cut proximal surface  112  as shown. 
     In FIGS. 26-28, tibial tray  113  is shown, which can be of metallic construction such as titanium alloy, for example. Tray  113  has a flat proximal surface  114  and a flat distal surface  115 . A plurality of mechanical fasteners such as spikes  116  on surface  115  can be used to enhance fixation of tibial tray  113  to the patient&#39;s proximal tibial  111 . Chemical fasteners (eg. cement) can also be used for fixation. A stem  117  can also be used to facilitate attachment of prosthesis  110  to the patient&#39;s tibia  111  at the tibial intramedullary canal. 
     The flat proximal surface  114  of tray  113  has a round post  118  with a hollow bore or socket  119 . The post  118  is spaced inwardly from the periphery  120  of tray  113  as shown in FIGS. 26 and 27. The post  118  is preferably positioned with an offset with respect to oval slot  126  in the articular insert to provide anterior stabilization in the total knee prosthesis. 
     FIGS. 29-31 show the insert  121  portion of the present invention, typically a polymeric plastic insert that fits tray  113 . Insert  121  has a flat distal surface  122  and a proximal surface  123  that includes curved portions. These curved portions are in the form of concavities  124 ,  125  receive shaped surfaces of a femoral prosthesis after total knee joint replacement surgery is completed. The flat distal surface  122  of insert  121  has an anterior to posterior extending generally oval shaped slot  126  as shown in FIG.  31 . 
     The slot  126  receives post  118  during use, enabling the insert  121  to slide in an anterior to posterior direction relative to tray  113 . 
     The present invention provides a rotating platform, mobile knee prosthesis  110  that incorporates anterior stabilization along with the ability to selectively constrain the movement of the articular surface from rotation and translation to rotation only. This is accomplished by using an opening  136  in insert  121  that communicates with slot  126  as shown in FIGS. 29-31 and  35 - 38 . The opening includes a frustoconical portion  137  that corresponds in shape to a similar frustoconically-shaped enlarged annular surface  134  of locking plug member  127 . The locking plug member  127  is shown more particularly in FIGS. 32,  33 , and  37 . 
     Locking plug member  127  includes a lower frustoconical surface  128 . The frustoconical outer surface  128  of locking member  127  below annular reference line  138  is sized and shaped to fit and form a taper lock connection with surface  139  of frustoconical socket  119  of post  118 . Above annular reference line  138 , the enlarged annular shoulder has a frustoconical shape as shown in FIG. 32 that corresponds generally to the size and shape of frustoconical portion  137  of opening  136  as shown in FIG.  36 . 
     When the locking member  127  is first placed through opening  136  of insert  121  and then into frustoconical socket  119  of post  118 , a locking connection is formed between the frustoconical outer surface  128  of locking member  127  and the frustoconical surface  139  of post  118 . This connection can be a taper lock type connection. 
     Locking screw  131  can be used to engage a correspondingly sized and shaped internally threaded opening  132  of tray  113  if desired. The locking screw  131  can include a head  140  that is enlarged so that the head  140  is retained by annular shoulder  133  of locking member  137  as shown in FIGS. 33 and 37. 
     In FIG. 38, arrows  141  indicate sliding movement of insert  121  relative to tray  113  as occurs when locking plug member  127  is removed. In such a situation, the insert  121  is free to slide with respect to tray  113 . The distal surface  122  of insert  121  slides upon the flat proximal surface  114  of tray  113 . Post  118  slides relative to slot  126 . 
     When locking member  127  is inserted through opening  136  and into socket  119  of post  118 , sliding movement is prevented. The enlarged annular shoulder  134  of locking member  127  engages the frustoconical portion  137  of opening  136  disallowing a sliding action of insert  121  relative to tray  113 . However, the enlarged annular shoulder  134  of locking member  127  is slightly spaced from frustoconical portion  137  of opening  136 , so that rotational movement of insert  121  relative to tray  113  is permitted. The second alternate embodiment of the present invention provides a rotating platform, mobile knee prosthesis  110  that incorporates anterior stabilization along with the ability to constrain movement of the articular surface from rotation and translation to rotation only. 
     FIGS.  39  and  40 - 51  show a third alternate embodiment of the apparatus of the present invention designated generally by the numeral  142  in FIG.  39 . Mobile bearing knee prosthesis  142  includes a tray  143  that can be attached to a patient&#39;s surgically cut proximal tibia using a stem  146  for example that occupies the patient&#39;s intramedullary canal. The tray  143  has a proximal surface  144  that receives an insert  159  and a distal surface  145  that registers upon the proximal tibia after the tibia has been surgically prepared to conform to the underside or distal surface  145  of tray  143 . 
     The proximal  144  surface of tray  143  provides a frustoconically-shaped socket  147  that can receive either of two selected plugs  148  or  154  (or any of the plug embodiments shown in FIGS.  18 - 21 ). The first plug  148  is designed to provide rotational movement only between insert  159  and tray  143 . The plug  148  has a frustoconical surface  149 , cylindrical surface  150 , beveled annular surface  151 , and a pair of opposed generally parallel flat end surfaces  152 ,  153 . 
     The second plug  154  is designed to provide both anterior to posterior translational movement between the insert  159  and tray  153  as well as rotational movement between the insert  159  and tray  153 . The plug  154  has a frustoconical surface  155 , a reduced diameter cylindrical surface  156 , and flat end surfaces  157 ,  158 . 
     During use, a surgeon selects either of the plugs  148  or  154 . The frustoconical surfaces  149  or  155  form a tight taper lock fit with a correspondingly shaped frustoconical socket  147  that communicates with the proximal  144  surface of tray  143 . Once the selected plug  148  or  154  has been inserted into frustoconical socket  147 , the insert  159  is placed on the selected plug  148  or  154 . The shape of the plug  148  or  154  that is selected determines whether or not the insert  159  can achieve only rotational movement relative to tray  143  or both rotational and anterior to posterior translational movement. 
     In the case of the plug  148 , only rotational movement between the insert  159  and the tray  143  can be attained. The plug  148  is shorter and thus only communicates with the cylindrically-shaped opening  164  on the bottom or distal surface  162  of insert  159 . Plug  148  once inserted in socket  147  only enables a rotational movement of the insert  159  on the tray  143 . The cylindrical surface  150  of plug  148  corresponds in size and shape to the circular opening  164  to accomplish a relatively close fit between cylindrical surface  150  of plug  148  and cylindrical opening  164  on insert  159 . 
     When both rotational and translational anterior to posterior movement are desired, the surgeon selects the plug  154 . The plug  154  is placed in socket  147  so that frustoconical surface  155  forms a taper lock fit with a correspondingly sized and shaped socket  147  of tray  143 . The smaller cylindrically-shaped portion  156  of plug  154  is taller in a proximal to distal direction than the cylindrically-shaped portion  150  of plug  148 . The portion  156  fits elongated slot  163  so that the insert  159  can translate in an anterior to posterior direction as the reduced diameter cylindrical portion  156  travels anterior to posterior in the direction of arrow  165  in FIG.  44 . However, the insert can also translate along a path  165  that is curved, or along a path  165  that forms an angle with a purely anterior to posterior direction line. The line  165  in FIG. 44 shows such a purely anterior to posterior line as the direction of travel. Because the slot  163  is at least as wide as the diameter of cylindrical portion  156 , rotational movement is also available between insert  159  and tray  143 . Insert  159  also provides proximal concavities  160 ,  161  for receiving a femoral component of a knee implant. 
     FIGS. 52-56 disclose a fourth alternative embodiment of this invention identified as prosthesis  210 , comprising a tibial tray  213 , a polymeric insert  28 , and a locking member  24 . In this embodiment, insert  28  and locking member  24  are the same as described above, but flange  221  is generally D-shaped, having a periphery extending laterally in the medial, lateral, and anterior directions from the outer surface of cylindrical section  220 , thereby creating recess  223  on the medial, lateral and anterior sides of section  220  (see FIGS. 55,  56 ). As evidenced by the following description, the assembly of prosthesis  210  is essentially identical to that of prosthesis  10  except for the shape of flange  221 . 
     Locking member  24  forms a removable connection with the socket  219 . Locking member  24  has an externally cylindrical section  25  that provides threads that correspond to the threads of internally socket  219  so that the locking member  24  can be threaded into the socket  219  as shown in FIG.  54 . 
     In order to assemble insert  28  to tray  213 , the distal surface of  29  of insert  28  is placed next to and generally parallel to the proximal surface  214  of tray  213 . Post  218  is aligned with vertical channel  33  of insert  28 . During assembly of insert  28  to tray  213 , the post  218  is oriented to enter the oval opening portion  37  of distal opening  36 . Once the distal surface  29  of insert  28  meets proximal surface  214  of tray  213 , flange  221  aligns with oval shaped slot  35  of vertical channel  33 . After such assembly, insert  28  is held in position by post  218 . This retention of insert  228  by post  218  occurs when flange  221  engages flat surface  40  to prevent separation if any rotation at all occurs between insert  28  and tray  213 . If no rotation has occurred between insert  28  and tray  213 , the oval shaped circular section  37  is sized to allow post  218  to be inserted into or withdrawn from channel  33 . 
     FIGS. 57-67 show a fifth alternate embodiment of the apparatus of the present invention designated generally by the numeral  200  in FIGS. 57-61. It should be understood that the embodiment of FIGS. 57-67 disclose an alternate construction for a polymeric insert  202  that interconnects with the same tibial tray  13  and stem  17  shown in FIGS. 1,  5 - 7 ,  14 - 16  of the preferred embodiment. In FIGS. 57-59, mobile bearing knee prosthesis  200  is shown as including tray  13 , polymeric insert  202 , and femoral component  236 . In FIG. 58, the femoral component  236  is shown attached to a patient&#39;s surgically cut distal femur  201 . 
     Polymeric insert  202  (see FIGS. 62-67) has a flat distal surface  203  and a proximal surface with a pair of concavities  204 ,  205 . Insert  202  also has periphery  206  and vertical channel  207 . The vertical channel  207  can be a slotted arrangement such as that shown in the preferred embodiment of FIGS. 1-17 and designated generally by the numeral  33 . Thus, the connection between post  18  of tray  13  and insert  202  can be the same connection that is shown and described with respect to the preferred embodiment of FIGS. 1-17 and shown particularly in FIGS. 1-7 and  15 - 17 , or as shown in FIGS. 52-56. 
     Vertical channel  207  can include a proximal cylindrically shaped section  208 , an oval shaped slot  209 , and a distal opening  224 . The distal opening  224  can include an oval section  226  and a half oval section  227  as shown in FIG.  66 . Flat surface  225  extends posteriorly of vertical channel  207  and more particularly posteriorly of the proximal cylindrically shaped section  208 , as shown in FIGS. 64 and 65. Flat surfaces  228 ,  229  register with the flange  21  of post  18 , respectively above and below the flange  21  to thereby prevent separation of polymeric insert  202  from post  18  unless the post  18  is aligned with oval section  226  of distal opening  224 . When the flange  21  of post  18  aligns with oval section  226  of distal opening  224 , insert  202  can be separated from tray  13 . 
     In the embodiment of FIGS. 57-68, insert  202  provides a central post  230 . Post  230  has proximal surface  231 , anterior surface  232 , posterior surface  233 , and sides  234 ,  235 . 
     Femoral component  236  is shown in FIGS. 57-61. Femoral component  236  has anterior portion  237 , a pair of posterior condylar portions  238 ,  239  and distal condylar portions  240 ,  241 . Femoral component  236  has central opening  242  and a horizontal bar cam  243  that extends between posterior condylar portions  238 ,  239  as best seen in FIGS. 59 and 68. A pair of vertical walls  244 ,  245  extend along opposing sides of central opening  242  and connect to both of the posterior condylar portions  238 , 239  and to horizontal bar  243 . The vertical walls  230 ,  231  also extend to and connect to surfaces  248 ,  249 ,  250 . The vertical walls  244 ,  245  can be generally parallel. 
     Femoral component  236  provides a plurality of flat surfaces that register against and conform to surgically cut flat surfaces that are provided on the patient&#39;s distal femur  201  as shown in FIG.  58 . These flat surfaces include flat surface  246  is an anterior surface, surface  247  which is a diagonally extending anterior surface that spans between anterior surface  246  and distal surface  248 . Distal surface  248  spans between diagonal surface  247  and posterior diagonal surface  249 . Posterior surface  250  is generally parallel to anterior flat surface  246 . These five flat surfaces  246 - 250  of femoral component  236  register against and conform to five surgically cut surfaces on a patient&#39;s distal femur  201 . Femoral component  236  can be securely fashioned to the patient&#39;s distal femur  201  using bone cement for example. 
     In FIGS. 60 and 61, a range of motion for the patient&#39;s knee fitted with mobile bearing knee prosthesis  200  as illustrated with arrows  252 ,  253 . For purposes of reference, the patient&#39;s central longitudinal axis  251  of the distal femur  201  is shown rotating posteriorly in the direction of arrow  253 . The anterior surface  237  of femoral component  236  is shown rotating in the direction of arrow  252 . FIG. 60 shows an extended position of the patient&#39;s knee wherein the longitudinal axis  251  of the femur  201  is generally aligned with the central longitudinal axis of the patient&#39;s tibia  11 . In FIG. 61, the knee is shown in a flexed position. In this position, horizontal bar cam  243  of femoral component  222  registers against the posterior surface  233  of central post  230  of polymeric insert  202 . In this position, the central post  230  causes femoral roll back on the tibia articular insert  202 . The posterior aspect of the tibia articular surface at  233  provides a lift that is created by generally following the curvature of the femoral component  236  in extension. This will provide a high degree of surface contact, conformity, subsequently providing low contact stress, in extension, where most of gait occurs. The post  230  can have a square or rectangular base that fits snugly within the central opening  242  of the femoral component  236 . 
     By providing the posterior stabilized design with the central post  230 , as the knee is flexed, the horizontal bar cam  243  acts as a cam on the femoral component  236  to engage the post  230  at surface  233  on the tibial component  202 , causing the femoral posterior condyles  238 ,  239  to roll back onto the tibial articular concavity surfaces  204 ,  205 . This “roll back” coupled with “climbing” the posterior aspect of the tibial articular surface at  233 , causes the femoral component  236  to be located out of the lowest aspect of the tibial articular surfaces  204 ,  205 . With this condition, any type of varus/valgus loading of the joint will cause one of the femoral condyles to apply higher downward loads than the opposing condyle. With a differential in loads, the tibial component  202  will freely spin until the higher loaded condyle displaces to the low point of the tibial articular surface. The central tibial post  216  forces the opposite condyle out of the posterior aspect of the tibial articular surface, thus creating a spin out. 
     The present invention allows for a free, unlimited rotation of the tibial insert  202  relative to its base plate  13 . All of the rotational constraint occurs between the femoral component  236  and the insert  202 . The present invention builds conformity of the central post  230  of the insert  202  relative to the box of the femur in rotation, but allowing for varus/valgus tilting. The present invention produces a generally trapezoidal insert post  230 . 
     A sixth alternate embodiment of the apparatus of the present invention is shown in FIGS. 69-81. In the embodiment of FIGS. 66-81, a mobile bearing knee prosthesis  254  features a two-part polymeric insert that includes first member  255  shown in FIGS. 69-75 and a second member  264  shown in FIGS. 69,  76 - 81 . Polymeric insert  255  (see FIGS. 70-75) has a central opening  256  that is bordered by a pair of spaced apart, generally parallel shoulders  257 ,  258  upon which second member  264  slides fore and aft. The insert  255  has a periphery  259  and a proximal surface with a pair of concavities  260 ,  261 . The insert member  255  includes a flat distal surface  262 . 
     The second insert member  264  has a proximal surface  265 , a distal surface  267  and a passageway  263  that extends between the surfaces  265 ,  267 . A pair of spaced apart, generally parallel shoulders  268 ,  269  are provided on opposing sides of insert  264  as shown in FIGS. 77,  79  and  81 . Flat surfaces  270 ,  271  are also provided on opposing sides of insert member  264 . The surface  270  is generally perpendicular to shoulder  268 . The surface  277  is generally perpendicular to the shoulder  267  as shown in FIG.  79 . 
     Insert member  264  provides a post  272 . Post  272  has flat, proximal surface  273 , anterior surface  274 , posterior surface  275 , and sides  276 ,  277 . The member  264  provides a curved anterior surface  278  that is correspondingly shaped to and fits against the correspondingly shaped concave surface  279  of member  255  at opening  256 . 
     During use, the shoulders  268 ,  269  of insert member  264  fit against and slide upon the shoulders  257 ,  258  of insert member  255 . Flat surfaces  270 ,  271  of insert member  264  engage and slide against flat surfaces  280 ,  281  of insert  255 . The insert member  264  slides upon the insert member  255  in an anterior to posterior direction because the opening  256  is longer than the insert member  264 . The opening  256  is larger in an anterior to posterior direction than the length of the insert member  264  measured from an anterior to posterior direction such as between surfaces  278  and  280 . 
     The present invention includes a posterior stabilizing post  272  secured to the central insert member  264 . The posterior stabilized post  272  captures or is captured by bearing insert component  255  to the tibial base plate  13  through an elongated slot or opening  256  in the bearing component  255 . The elongated opening or slot  256  in the bearing component member  255  allows it to translate anteriorly and posteriorly with respect to the posterior stabilized post  272  of the insert member  264 . The bearing component  255  may also rotate with respect to the tibial base plate  13  in conjunction with the posterior stabilized post  272 . 
     The bearing component  255  has two concave surfaces  260 ,  261  that are configured to articulate with the convex surfaces (condylar portions)  240 ,  241  of the femoral component  236  at full extension. The posterior stabilized post  272  articulates with a horizontal bar cam  243  of the femoral component  236  to provide femoral roll back. 
     The bearing design of the present invention thus consists of a bearing articular insert  255  with a separate posterior stabilized post component  264  that may have one or more degrees of freedom. The bearing articular insert  251  has two concave surfaces  260 ,  261  that articulate with the convex surfaces (condylar portions)  240 ,  241  of the femoral component  236  at full extension. The posterior stabilized post  272  articulates with a recess or cam  243  of the femoral component  236  to provide femoral roll back. The rotational freedom of the posterior stabilized post  272  maintains contact with the femoral bar cam  243  during external or internal rotation of femoral component  236 . 
     The posterior stabilized member  255  has a flat distal surface  262  that articulates with the tibial base plate  13 . A tee slot  266  is located on the distal surface  267  and articulates with a tee post  18  on the tibial base plate  13  (see FIGS. 1-17 for such a tee slot and tee post connection). A through hole  263  in the component  264  is located such that a rotation peg (such as peg  24  in FIGS. 1-7) can capture the component  264  to the tibial base plate  13  while the tee slot of the insert component  264  is engaged with a tee post  18  of the tibial base plate. Rotation peg  24  allows only rotational freedom of the insert component  264  with respect to the tibial base plate  13 . The elongated slot  256  of the bearing component  255  is larger than the posterior stabilized post carrying component  255  in the anterior-posterior direction such that the bearing component has limited translation with respect to the posterior stabilized post. The bearing component  255  may also rotate with respect to the tibial base plate  13  in conjunction with the posterior stabilized post component  264 . 
     Horizontal bar cam mechanism  243  on the femoral component  236  is preferably a concavely shaped cylinder as shown in FIGS. 59 and 68, that registers against and engages the convex posterior surface  275  of the posterior stabilized post  272 . The internal/external rotation of the posterior stabilized post component  264  with the femoral component  236  maintains this contact throughout the range of motion. 
     As an alternate construction, the second (central) insert member  264  could rotate only with respect to the tibial prosthesis, and the first (peripheral) insert member could both rotate and translate with respect to the tray. 
     PARTS LIST 
     The following is a list of suitable parts and materials for the various elements of the preferred embodiment of the present invention. 
     
       
         
               
               
               
             
           
               
                   
                   
               
               
                   
                 Part Number 
                 Description 
               
               
                   
                   
               
             
             
               
                   
                  10 
                 mobile bearing knee prosthesis 
               
               
                   
                  11 
                 tibia 
               
               
                   
                  12 
                 surgically cut proximal surface 
               
               
                   
                  13 
                 tray 
               
               
                   
                  13A 
                 tray 
               
               
                   
                  14 
                 flat proximal surface 
               
               
                   
                  15 
                 flat distal surface 
               
               
                   
                  16 
                 spike 
               
               
                   
                  17 
                 stem 
               
               
                   
                  18 
                 post 
               
               
                   
                  19 
                 internally threaded socket 
               
               
                   
                  20 
                 cylindrically-shaped section 
               
               
                   
                  21 
                 flange 
               
               
                   
                  22 
                 periphery 
               
               
                   
                  23 
                 recess 
               
               
                   
                  24 
                 fastener 
               
               
                   
                  25 
                 externally threaded section 
               
               
                   
                  26 
                 head 
               
               
                   
                  27 
                 tool receptive socket 
               
               
                   
                  28 
                 insert 
               
               
                   
                  29 
                 flat distal surface 
               
               
                   
                  30 
                 concavity 
               
               
                   
                  31 
                 concavity 
               
               
                   
                  32 
                 periphery 
               
               
                   
                  33 
                 vertical channel 
               
               
                   
                  34 
                 proximal, cylindrically-shaped 
               
               
                   
                   
                 section 
               
               
                   
                  35 
                 oval shaped slot 
               
               
                   
                  36 
                 distal opening 
               
               
                   
                  37 
                 oval section 
               
               
                   
                  38 
                 half oval section 
               
               
                   
                  39 
                 flat surface 
               
               
                   
                  40 
                 flat surface 
               
               
                   
                  41 
                 arrow/angle 
               
               
                   
                  42 
                 post 
               
               
                   
                  43 
                 cylindrical surface 
               
               
                   
                  44 
                 circular top 
               
               
                   
                  45 
                 rectangular base 
               
               
                   
                  46 
                 inclined side wall 
               
               
                   
                  47 
                 tray socket 
               
               
                   
                  48 
                 inclined surface 
               
               
                   
                  49 
                 post 
               
               
                   
                  50 
                 vertical side wall 
               
               
                   
                  51 
                 inclined surface 
               
               
                   
                  52 
                 flat top 
               
               
                   
                  53 
                 post 
               
               
                   
                  54 
                 vertical side wall 
               
               
                   
                  55 
                 vertical end wall 
               
               
                   
                  56 
                 flat top 
               
               
                   
                  57 
                 rectangular base 
               
               
                   
                  58 
                 inclined surface 
               
               
                   
                  59 
                 post 
               
               
                   
                  60 
                 flat top 
               
               
                   
                  61 
                 vertical side wall 
               
               
                   
                  62 
                 rectangular base 
               
               
                   
                  63 
                 inclined surface 
               
               
                   
                  64 
                 insert opening 
               
               
                   
                  65 
                 arrow 
               
               
                   
                  66 
                 arrow 
               
               
                   
                 110 
                 mobile bearing knee prosthesis 
               
               
                   
                 111 
                 tibia 
               
               
                   
                 112 
                 surgically cut proximal surface 
               
               
                   
                 113 
                 tray 
               
               
                   
                 114 
                 flat proximal surface 
               
               
                   
                 114A 
                 opening 
               
               
                   
                 115 
                 flat distal surface 
               
               
                   
                 116 
                 spike 
               
               
                   
                 117 
                 stem 
               
               
                   
                 118 
                 post 
               
               
                   
                 119 
                 socket 
               
               
                   
                 120 
                 periphery of tray 
               
               
                   
                 121 
                 insert 
               
               
                   
                 122 
                 flat distal surface 
               
               
                   
                 123 
                 proximal surface 
               
               
                   
                 124 
                 concavity 
               
               
                   
                 125 
                 concavity 
               
               
                   
                 126 
                 slot 
               
               
                   
                 127 
                 locking plug member 
               
               
                   
                 128 
                 frustoconical outer surface 
               
               
                   
                 129 
                 socket 
               
               
                   
                 130 
                 threaded bore 
               
               
                   
                 131 
                 locking screw 
               
               
                   
                 132 
                 internally threaded opening 
               
               
                   
                 133 
                 annular shoulder 
               
               
                   
                 134 
                 enlarged annular shoulder 
               
               
                   
                 135 
                 periphery of insert 
               
               
                   
                 136 
                 opening 
               
               
                   
                 137 
                 frustoconical portion 
               
               
                   
                 138 
                 annular reference line 
               
               
                   
                 139 
                 frustoconical surface 
               
               
                   
                 140 
                 enlarged head 
               
               
                   
                 141 
                 arrows 
               
               
                   
                 142 
                 mobile bearing knee prosthesis 
               
               
                   
                 143 
                 tray 
               
               
                   
                 144 
                 proximal surface 
               
               
                   
                 145 
                 distal surface 
               
               
                   
                 146 
                 stern 
               
               
                   
                 147 
                 frustoconical socket 
               
               
                   
                 148 
                 plug 
               
               
                   
                 149 
                 frustoconical surface 
               
               
                   
                 150 
                 cylindrical surface 
               
               
                   
                 151 
                 beveled annular surface 
               
               
                   
                 152 
                 fiat end surface 
               
               
                   
                 153 
                 flat end surface 
               
               
                   
                 154 
                 plug 
               
               
                   
                 155 
                 frustoconical surface 
               
               
                   
                 156 
                 reduced diameter 
               
               
                   
                   
                 cylindrical surface 
               
               
                   
                 157 
                 flat end surface 
               
               
                   
                 158 
                 flat end surface 
               
               
                   
                 159 
                 insert 
               
               
                   
                 160 
                 proximal concavity 
               
               
                   
                 161 
                 proximal concavity 
               
               
                   
                 162 
                 flat distal surface 
               
               
                   
                 163 
                 elongated slot 
               
               
                   
                 164 
                 cylindrical opening 
               
               
                   
                 165 
                 arrow 
               
               
                   
                 200 
                 mobile bearing knee prosthesis 
               
               
                   
                 201 
                 surgically cut femur 
               
               
                   
                 202 
                 polymeric insert 
               
               
                   
                 203 
                 flat distal surface 
               
               
                   
                 204 
                 concavity 
               
               
                   
                 205 
                 concavity 
               
               
                   
                 206 
                 periphery 
               
               
                   
                 207 
                 vertical channel 
               
               
                   
                 208 
                 proximal cylindrically-shaped 
               
               
                   
                   
                 section 
               
               
                   
                 209 
                 oval shaped slot 
               
               
                   
                 210 
                 mobile bearing knee prosthesis 
               
               
                   
                 213 
                 tray 
               
               
                   
                 214 
                 flat proximal surface 
               
               
                   
                 215 
                 flat distal surface 
               
               
                   
                 216 
                 spike 
               
               
                   
                 217 
                 stem 
               
               
                   
                 218 
                 post 
               
               
                   
                 219 
                 internally threaded socket 
               
               
                   
                 220 
                 cylindrically-shaped section 
               
               
                   
                 221 
                 flange 
               
               
                   
                 222 
                 periphery 
               
               
                   
                 223 
                 recess 
               
               
                   
                 224 
                 distal opening 
               
               
                   
                 225 
                 fiat surface 
               
               
                   
                 226 
                 oval section 
               
               
                   
                 227 
                 half oval section 
               
               
                   
                 228 
                 fiat surface 
               
               
                   
                 229 
                 flat surface 
               
               
                   
                 230 
                 central post 
               
               
                   
                 231 
                 proximal surface 
               
               
                   
                 232 
                 anterior surface 
               
               
                   
                 233 
                 posterior surface 
               
               
                   
                 234 
                 side 
               
               
                   
                 235 
                 side 
               
               
                   
                 236 
                 femoral component 
               
               
                   
                 237 
                 anterior portion 
               
               
                   
                 238 
                 posterior condylar portion 
               
               
                   
                 239 
                 posterior condylar portion 
               
               
                   
                 240 
                 distal condylar portion 
               
               
                   
                 241 
                 distal condylar portion 
               
               
                   
                 242 
                 central opening 
               
               
                   
                 243 
                 horizontal bar cam 
               
               
                   
                 244 
                 vertical wall 
               
               
                   
                 245 
                 vertical wall 
               
               
                   
                 246 
                 flat surface 
               
               
                   
                 247 
                 flat surface 
               
               
                   
                 248 
                 flat surface 
               
               
                   
                 249 
                 flat surface 
               
               
                   
                 250 
                 fiat surface 
               
               
                   
                 251 
                 central longitudinal axis 
               
               
                   
                 252 
                 arrow 
               
               
                   
                 253 
                 arrow 
               
               
                   
                 254 
                 mobile bearing knee prosthesis 
               
               
                   
                 255 
                 polymeric insert bearing component 
               
               
                   
                 256 
                 central opening 
               
               
                   
                 257 
                 shoulder 
               
               
                   
                 258 
                 shoulder 
               
               
                   
                 259 
                 periphery 
               
               
                   
                 260 
                 concavity 
               
               
                   
                 261 
                 concavity 
               
               
                   
                 262 
                 distal surface 
               
               
                   
                 263 
                 through hole 
               
               
                   
                 264 
                 central insert component 
               
               
                   
                 265 
                 proximal surface 
               
               
                   
                 266 
                 tee slot 
               
               
                   
                 267 
                 distal surface 
               
               
                   
                 268 
                 shoulder 
               
               
                   
                 269 
                 shoulder 
               
               
                   
                 270 
                 flat surface 
               
               
                   
                 271 
                 flat surface 
               
               
                   
                 272 
                 post 
               
               
                   
                 273 
                 flat proximal surface 
               
               
                   
                 274 
                 anterior surface of post 
               
               
                   
                 275 
                 posterior surface of post 
               
               
                   
                 276 
                 side 
               
               
                   
                 277 
                 side 
               
               
                   
                 278 
                 curved anterior surface 
               
               
                   
                 279 
                 concave surface 
               
               
                   
                 280 
                 posterior surface 
               
               
                   
                 281 
                 flat surface 
               
               
                   
                 282 
                 flat surface 
               
               
                   
                   
               
             
          
         
       
     
     The foregoing embodiments are presented by way of example only; the scope of the present invention is to be limited only by the following claims.