1. Department of Medical Research and Management for Musculoskeletal Pain, 22nd Century Medical & Research Center, Faculty of Medicine, The University of Tokyo: 7-3-1 Hongo, Bunkyo, Tokyo 113-8655, Japan
2. Japan Labour, Health and Welfare Organization, Kanto Rosai Hospital, Japan
3. Department of Orthopaedic Surgery, The University of Tokyo, Japan
4. Department of Orthopaedic Surgery, Teikyo University School of Medicine, Japan