Patent ID: 7105027

Claim:
A knee joint prosthesis comprising: a femoral component having a fixation surface configured for attaching to a femur and a sliding surface; a tibial tray having a fixation surface configured for attaching to a tibial and a sliding surface; and an insert that fits between the femoral component and the tibial tray when the prosthesis is installed in a subject, the insert having a femoral side and a tibial side, wherein the femoral side is shaped to slidingly interface with the sliding surface of the femoral component during flexion of the knee and the tibial side is shaped to slidingly interface with the sliding surface of the tibial tray, wherein, at regions where the sliding surface of the femoral component interfaces with the insert during extension and an initial range of flexion of the knee, a radius of curvature (R 1 ) of the sliding surface of the femoral component for flexion rotation is larger than a radius of curvature (R 3 ) of the sliding surface of the femoral component for varus/valgus rotation, and wherein the sliding surface of the tibial tray is spherically or toroidally curved.