Method and apparatus for determining the direction of the mechanical axis of the femur of a patient in relation to the corresponding knee of the patient in connection with resecting the distal femur for the reception of a femoral knee prothesis include at least partially suspending the patient's leg to locate the knee at a suspended position wherein external forces on the knee, such as the weight of the leg, are balanced and the knee remains essentially stationary at the suspended position, applying a force to the femur at a predetermined location relative to the mechanical axis of the femur, directing the applied force in a direction such that the knee remains undeflected from the suspended position while the force is applied to the femur in that direction, and employing that direction of the applied force to indicate the direction of the mechanical axis of the femur.