| 摘要 |
A knee prosthesis comprising a femoral component and a tibial component. The femoral component comprises a medial femoral condyle having a medial femoral condylar surface and a lateral femoral condyle having a lateral femoral condylar surface. The tibial component comprises a medial tibial condyle having a medial tibial condylar surface and a lateral tibial condyle having a lateral tibial condylar surface. The medial femoral condylar surface comprises a part-spherical convex surface and the medial tibial condylar surface comprises a part-spherical concave surface, the part-spherical surfaces being arranged to enable the medial femoral condyle to engage in sphere-in-sphere engagement with the medial tibial condyle. The sphere-in-sphere engagement provides anterior-posterior stability of the femoral component relative to the tibial component. The lateral tibial condylar surface comprises a track surface for the lateral femoral condyle to move across as the medial condyle pivots around the sphere-in-sphere engagement. The track surface is posteriorly unrestricted to permit the lateral femoral condylar surface to contact the track surface at a range of contact positions as the medial femoral condyle pivots relative to the medial tibial condyle around the sphere-in-sphere engagement. |
