1. Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine , Osaka, Japan
2. Department of Orthopaedic Surgery, Osaka Saiseikai Nakatsu Hospital , Osaka, Japan
3. Center for Senile Degenerative Disorders, Osaka City University Graduate School of Medicine , Osaka, Japan
4. Search Institute for Bone and Arthritis Disease, Shirahama Foundation for Health and Welfare , Wakayama, Japan