A cutting block assembly comprising first and second interlocking blocks for resecting a distal femur. The first block has a first surface for providing a guiding surface for making an anterior chamfer cut on the femur and a second surface for providing a guiding surface for making a posterior chamfer cut on the femur. The second block is adapted to detachably couple to the first block. The second block has a first surface for providing a guiding surface for making an anterior cut on the femur and a second surface for providing a guiding surface for making a posterior cut on the femur.
