KNEE JOINT PROSTHESIS

摘要

A knee joint prosthesis which comprises a tibial component (4, 6) and a femoral component (2). The femoral component has condyles (14, 16) which act against the tibial component, directly or indirectly, during flexing of the knee. A cam (20) on the femoral component acts against a post (26) on the tibial component at high flex angles. The surface of the post which is contacted by the cam at high flex angles is convex when the post viewed generally perpendicular to the tibial bone contact and bearing surfaces, and the femoral bearing surface which is provided by the cam, where it contacts the convex surface of the post at high flex angles, is locally concave (32) when viewed along the surface of the post which contacts the cam so that the area of contact between the post and the cam is greater at high flex angles than at lower flex angles.

主权项

1. A knee joint prosthesis which comprises:
a. a tibial component which has a bone contact surface for contacting a patient's resected tibia, and an opposite bearing surface, and a post extending from the bearing surface in a direction generally away from the bone contact surface, and b. a femoral component which has a bearing surface provided by medial and lateral condyles, and by a cam which is located between the condyles at or towards their posterior ends, in which the condyles of the femoral bearing surface act against the bearing surface of the tibial component, directly or indirectly, during flexing of the knee and the cam on the femoral component acts against the post on the tibial component at high flex angles, and in which: a. the surface of the post which is contacted by the cam at high flex angles is convex when the post viewed generally perpendicular to the tibial bone contact and bearing surfaces, and b. the femoral bearing surface which is provided by the cam, where it contacts the convex surface of the post at high flex angles, is locally concave when viewed along the surface of the post which contacts the cam so that the area of contact between the post and the cam is greater at high flex angles than at lower flex angles.