There is provided a method and system for determining a distal cut thickness and posterior cut thickness for a femur in a knee replacement operation, the method comprising: performing a tibial cut on a tibia performing soft tissue balancing based on a desired limb alignment measuring an extension gap between the femur and said tibial cut while in extension measuring a flexion gap between the femur and the tibial cut while in flexion calculating a distal cut thickness and a posterior cut thickness for the femur using the extension gap and the flexion gap and taking into account a distal thickness and posterior thickness of a femoral implant and performing said femoral cut according to the distal cut thickness and posterior cut thickness.
