Abstract: A knee prosthesis includes a tibial component, a bearing and a femoral component. The tibial component includes a platform and at least one rib extending upwardly and forwardly, a front edge of upper surface of the platform is provided with at least one front lug boss, and back edge of the upper surface of the platform is provide with at least one back lug boss. The lower surface of the bearing is provided with a groove matching with the at least one rib, a front slot matching with the front lug boss and a back slot; the femoral component is articulated with the bearing; at least one rib is provided with a medial wall and a lateral wall, one of the them is provided with a bent portion and formed with a first inclined surface which extends in a direction away from the other one.

Abstract: A femoral prosthesis and a knee prosthesis are provided. The femoral prosthesis includes a condyle surface having a first surface section contacting a tibial joint surface over a first range of flexion angles and a second surface section contacting the tibial joint surface over a second range of flexion angles; the first range of flexion angles from a first to a second flexion angle; the second range of flexion angles from the second to a third flexion angle; the first flexion angle selected from ?20° to 0°, the second flexion angle selected from 45° to 75°, the third flexion angle selected from 50° to 90° and the third flexion angle greater than the second flexion angle; the first surface section having a radius of curvature of a constant length, and the second surface section having a radius of curvature that decreases from a front end to the rear end.