Abstract: A knee joint prosthesis having independently interchangeable components. The knee joint prosthesis includes a femoral component having a first bearing surface defined at least in part by a first radius in the coronal plane. The femoral component further includes a second bearing surface defined at least in part by a second radius in the coronal plane, the second radius being displaced from the first radius. The distance between the center of the first radius to the center of the second radius is substantially constant and does not depend on the size of the femoral component. The knee joint prosthesis further includes a tibial component which is operable to engage the femoral component.

Abstract: A method and surgical instrument is provided for the in situ clamping engagement and reaming of the human patella bone in preparation for the installation of a patellar button prosthesis, the clamp including a rectangular frame wherein a pair of handles are mounted for parallel movement whereby to move their respective jaws into clamped engagement with the opposite faces of the patella, and a guide head defining a fixed stop; and a reaming device including a reamer shaft disposed for rotation relative to the guide head, a depth adjustment head connected to the shaft and adapted to abut the fixed stop, and a reamer blade mounted to the shaft. The shaft is provided with indicia to indicate the thickness of the patella that will remain after the resection.