1. Department of Orthopaedic Surgery, Okayama University, 2-5-1 Shikata-cho, Kita-ku, Okayama 700-8558, Japan
2. Department of Orthopaedic Surgery, Kurashiki Municipal Hospital, 2-39 Kojima-ekimae, Kurashiki 711-0921, Japan
3. Department of Human Morphology, Okayama University, 2-5-1 Shikata-cho, Kita-ku, Okayama 700-8558, Japan