KNEE JOINT PROSTHESIS WITH SPINOUT PREVENTION

A knee joint prosthesis is provided. The prosthesis includes a femoral component for mounting to the distal end of a femur, a tibial component for mounting to the resected proximal end of the tibia and a bearing disposed between the femora l and tibial components. The tibial component includes a superior bearing surface with a recess extending distally into the bearing surface. The bearing includes an inferio r bearing surface for engagement on the superior bearing surface of the tibial component. Additionally, the bearing includes a projection that is rotatably engaged in the recess of the tibial component. Rotation of the bearing relative to the tibial component i s limited by a stop extending from the superior bearing surface of the tibial component. Th e stop is engaged in a slot formed in the inferior surface of the bearing. The slot is concentric about the rotational axis and extends through an arc consistent with the desired maximum range of rotation. Engagement of the stop in the slot limits rotation and prevents spinout of the knee prosthesis.