A knee joint prosthesis includes a femoral component (110) having an anterior side, a posterior side, a pair of laterally spaced condylar portions (114,116), and an intercondylar portion (130) 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. The prosthesis also includes a tibial component (200) including a platform (210) having an upper surface (214) that includes first and second laterally spaced concavities (224,226). Each concavity is adapted for receiving one condylar portion of the femoral component. The tibial component has a tibial post (240) for reception in the intercondylar recess of the femoral component. The tibial post has a saddle shaped anterior cam surface that is complementary to the saddle shaped anterior cam surface of the femoral component.
