A novel knee prosthesis with asymmetrical joint surfaces and natural behaviour

The natural tibiofemoral joint (TFJ) functions according to the asymmetrical joint surfaces and the rolling-gliding mechanism. In the sagittal section, the human TFG is the tibial plateau on the medial concave side and curved on the lateral convex. With the asymmetrical joint surfaces, the flexion of the knee consists of two parts: the femur rolls backwards over the tibia plateau, and further flexion causes increased gliding. In most knee arthroplasties, these factors are not taken into account; instead, they are equipped with symmetrical medial and lateral joint surfaces. Thereby, the curvatures of the sagittal contours and the medial lateral joint surfaces create a common axis of rotation. The goal of this study was therefore to develop a novel knee endoprosthesis with asymmetrical joint surfaces and natural rolling-sliding behaviour.