1. Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017, Japan
2. Department of Orthopaedic Surgery, Mitsubishi Kobe Hospital, 6-1-34 Wadamiya-Dori, Hyogo-ku, Kobe, Hyogo 652-0863, Japan