An apparatus and method is disclosed of identifying the original femorotibial joint location in a revision knee replacement of a patient. The invention comprises selecting a first reference point (H) relative to the femoral head of the patient. A second reference point (A) is selected relative to the adductor tubical of the femur of the patient. The femorotibial joint location (J) is calculated through a relationship between the first reference point (H) and the second reference point (A) of the patient. The method and apparatus defines a femur reference plane to assist in establishing the correct rotation of the femur in a revision knee replacement of a patient.