MOBILE BEARING KNEE PROSTHESIS

摘要

A mobile bearing knee prosthesis enables a surgeon to convert a mobile beari ng insert having articular surfaces, supported by a tibial base plate or tray from a rotating and translating prosthesis to one that rotates only. This conversion is accomplished with a fastener or locking member that connects through an opening in the insert to the tibial base plate. This prosthesis c an be used as part of a total knee surgery when the surgeon chosses to use a prosthesis that incorporates a movable articular surface. In one embodiment, a projecting portion extends proximally from the insert and cooperates with a cam on the femoral component. The projecting portion can be a post extending up from the proximal surface of the insert and the femoral component include s an intercondylar surface that may contact the post to constrain the relative motion between the femoral component and the insert. In another embodiment, the insert is a two part assembly that includes a larger member with a centr al opening and a smaller member that fits the opening.