Abstract: A knee prosthesis system includes a tibial component having a tray element, a femoral component having laterally spaced apart condylar elements, a modular bearing member for being selected and seated within the tray element of the tibial component to provide a bearing support for the condylar elements of the femoral component for operation of the knee prothesis, the bearing member including an eminence projecting superiorly for reception between the condylar elements of the femoral component to provide controlled restraint against excessive relative movement between the femoral component and the tibial component, including control of the anterior-posterior portions of the relative movement, and a stabilizing post within the eminence for reinforcing and stabilizing the eminence against forces exerted upon the eminence during operation of the knee prosthesis.