Posterior stabilized knee prosthesis

Abstract

A knee joint prosthesis includes a femoral component having an anterior side, a posterior side, a pair of laterally spaced condylar portions, and an intercondylar portion joining the condylar portions and including a recess. A cam surface is located adjacent the intercondylar recess on the anterior side of the femoral component and has a saddle shape that is defined by an at least substantially concave first radius of curvature and a convex third radius of curvature that is perpendicular to the concave first radius of curvature. The prosthesis also includes a tibial component including a platform having an upper surface that includes first and second laterally spaced concavities. Each concavity is adapted for receiving one condylar portion of the femoral component. The tibial component has a tibial post for reception in the intercondylar recess of the femoral component. The tibial post has a saddle shaped anterior earn surface that is complementary to the saddle shaped anterior cam surface of the femoral component and is defined by an at least substantially convex second radius of curvature and a concave fourth radius of curvature that is perpendicular to the convex second radius of curvature.

1 - 15 . (canceled) 
     
     
         16 . A method of implanting a knee joint prosthesis comprising the steps of: forming an arcuate shaped notch in the femur;
 providing a femoral component having an anterior side, a posterior side, a pair of laterally spaced condylar portions, and an intercondylar portion joining the condylar portions and including a recess, the femoral component having a cam surface located adjacent the intercondylar recess on the anterior side of the femoral component, wherein the intercondylar portion includes an arcuate shaped roof that has a shape complementary to the notch in the femur;   coupling the femoral component with the femur by inserting the arcuate shaped roof in the notch formed in the femur;   providing a tibial component including a platform having an upper surface that includes first and second laterally spaced concavities and a tibial post;   coupling the tibial component to the tibia; and   mating the tibial component to the femoral component by inserting the tibial post in the intercondylar recess of the femoral component and receiving the condylar portions of the femoral component within the first and second laterally spaced concavities.   
     
     
         17 . The method of  claim 16 , wherein the tibial post has a saddle shaped anterior cam surface that is defined by an at least substantially convex radius of curvature and a concave radius of curvature that is perpendicular to the convex radius of curvature. 
     
     
         18 . The method of  claim 16 , wherein the femoral component includes a cam surface located adjacent the intercondylar recess on the anterior side of the femoral component, the anterior cam surface having a saddle shape and being defined by an at least substantially concave radius of curvature and a convex radius of curvature that is perpendicular to the concave radius of curvature. 
     
     
         19 . The method of  claim 16 , wherein the tibial post has a saddle shaped anterior cam surface that is defined by a convex radius of curvature and the femoral component includes a complementary saddle shaped cam surface located adjacent the intercondylar recess on the anterior side of the femoral component and being defined by a concave radius of curvature, the two saddle shaped cam surfaces being in contact with one another and wherein the convex radius of curvature of the post is less than the concave radius of curvature of the femoral component. 
     
     
         20 . The method of  claim 19 , wherein the convex radius of curvature is equal to or less than 95% of the concave radius of curvature. 
     
     
         21 . (canceled) 
     
     
         22 . A method for implanting a femoral component that is part of a knee joint prosthesis comprising the steps of:
 removing an arcuate shaped bone segment from a femur to create an arcuate shaped notch; and   implanting the femoral component into the femur by inserting an intercondylar portion into the notch.   
     
     
         23 . The method of  claim 22 , wherein the notch has a rounded shape. 
     
     
         24 . The method of  claim 22 , wherein the intercondylar portion includes an arcuate shaped roof that is defined by a single radius. 
     
     
         25 . The method of  claim 24 , wherein the arcuate shaped roof has a semi-circular shape. 
     
     
         26 . The method of  claim 22 , wherein the notch has a semi-circular shape. 
     
     
         27 . The method of  claim 22 , wherein the step of removing the arcuate shaped bone segment comprises the step of using a rotating reamer. 
     
     
         28 . The method of  claim 24 , wherein the arcuate shaped roof extends between a pair of opposing side walls, wherein the arcuate shaped roof is defined by a single radius, the femoral component having a cam surface located adjacent the intercondylar recess on the anterior side, the cam surface being defined by an at least substantially concave radius of curvature and a convex radius of curvature perpendicular to the concave radius of curvature so as to form a saddle shaped cam surface that is configured for articulation with a tibial insert. 
     
     
         29 . The method of  claim 22 , wherein an angle of the intercondylar portion is between about 20° to about 35°.