Abstract: A positioning and template system for preparing a femur for knee replacement. The system includes a datum block, a datum block placement assembly, and a cutting template assembly. The datum block placement assembly is reversibly attachable to the datum block. Further, the datum block placement assembly positions the datum block on the femur in a measured position relative to the transepicondylar axis of the femur when the datum block placement assembly is attached to the datum. Finally, the cutting template assembly is reversibly attachable to the datum block in place of the datum block placement assembly to correctly position the cutting template assembly for guiding femoral cuts in a knee replacement surgery.