A system and method for aligning a patient’s leg, for establishing the ultimate alignment of the leg prior to making a horizontal femoral cut or a horizontal tibial cut, for preparing the distal femur for receiving a femoral implant, and for making the horizontal, femoral and tibial cuts. Since the lengthwise dimension of a hub 5A is smaller than that of a prior art, the weight and cost can be decreased that much. The first signal transmission lines and the second signal transmission lines are respectively used to connect the signal feed portions with the first radiation portions and the second radiation portions. A result display portion causes a display of a result of evaluation of the recognition performance of the recognition program evaluated by the recognition evaluation portion.