A shock absorbent system for a joint prosthesis includes a shock absorbent material. The shock absorbent system may be used in both hip and knee joint prostheses. In one example, a knee joint prosthesis includes a tibial plate, a femoral component having a moveable condyle in contact with a shock absorbent material, wherein movement of the moveable condyle deforms the shock absorbent material, and a tray insert disposed between the tibial plate and the moveable condyle. The moveable condyle deforms the shock absorbent material under compressive forces between the tibial plate and the femoral component, thereby absorbing impact loads
