1. Department of Orthopedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine , 465 Kajii-cho, Kamigyo-ku, Kyoto 602-8566, Japan
2. Department of Orthopaedics, Fukuchiyama City Hospital , 231 Atsunaka-cho, Fukuchiyama, Kyoto 620-8505, Japan