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 baseplate or tray fr om a rotating and translating prosthesis to one that rotates only. This conversion is accomphished with a fastener or locking member that connects through an opening in the insert to the tibial baseplate. This proximal can be used as part of a total knee surgery when the surgeon chooses 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 can be a post extending up from the proximal surface of the insert and the femoral component includes 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.