US Patent 6869447 Prosthetic knee implant with modular augment

A modular prosthetic knee implant system includes a femoral component, a femoral stem, a femoral stem collar, an augment and a bolt. The modular prosthetic knee system can be assembled in different ways. If assembled without the augment, the stem is at a valgus angle. If assembled with the augment, the stem is at a neutral angle. The stem collar has an inferior surface that is angled with respect to its superior surface, and the augment has a superior surface that is angled with respect to its inferior surface. The components also include mating anti-rotation members to fix the relative positions of the members.