Instrument system for preparing a distal femur for a posteriorly stabilized femoral component of a knee prosthesis

An instrument system for preparation of a longitudinally extending distal femur for the implant of a posteriorly stabilized femoral component of a knee prosthesis, the preparation including removal of natural bone in the intercondylar area of the distal femur to prepare a femoral notch, including a patella recess, subsequent to the execution of distal, anterior and chamfer cuts establishing a prepared distal femur having distal, anterior and chamfer surfaces, the instrument system comprising:

• a femoral notch cutting guide for placement over the distal, anterior and chamfer surfaces of the prepared distal femur, the femoral notch cutting guide having a first portion including a first surface for overlying the distal surfaces, a second portion including a second surface for overlying the anterior surfaces and a third portion including a third surface for overlying the chamfer surfaces, the femoral notch cutting guide including a first guideway extending along the femoral notch cutting guide in a direction transverse to the longitudinal extent of the distal femur, and a second guideway extending along the femoral notch cutting guide in a generally longitudinal direction;
• and
• a femoral notch cutting punch having a length extending between opposite ends, a cutting edge at one of the opposite ends, and coupling means at the other of the opposite ends, the femoral notch cutting punch including follower means extending along the length of the femoral notch cutting punch, the follower means being complementary to each of the first and second guideways such that upon engagement of the follower means with the first guideway and the application of a cutting force at the coupling means the femoral notch cutting punch is advanced transversely, in a generally distal direction, to remove natural bone and establish the patella recess, and upon engagement of the follower means with the second guideway and the application of a further cutting force at the coupling means, the femoral notch cutting punch is advanced longitudinally, in a generally proximal direction, to remove natural bone to complete the femoral notch.