1. Okimoto Clinic; Kure Japan
2. Department of Biostatistics, Clinical Research Support Center; University of Tokyo Hospital; Bunkyo-ku Tokyo Japan
3. Department of Orthopaedic Surgery; Shimura Hospital; Hiroshima Japan
4. Department of Orthopaedic Surgery; Obase Hospital; Miyako-gun Fukuoka Japan
5. Tsurukami Clinic of Orthopaedics and Rheumatology; Tamana Japan
6. Department of Orthopaedic Surgery; Moji Medical Center; Kitakyushu Japan
7. Department of Orthopaedic Surgery; Social Insurance Nogata Hospital; Nogata Japan
8. Department of Orthopaedic Surgery; Kaisei General Hospital; Sakaide Japan
9. Department of Orthopaedic Surgery; Hirao Clinic; Hiroshima Japan
10. Department of Orthopedic Surgery; Ken-Ai Memorial Hospital; Onga-gun Fukuoka Japan
11. Department of Orthopaedic Surgery; Sanzai Hospital; Saito Japan
12. Department of Orthopaedic Surgery; Chugoku-Rosai Hospital; Kure Japan
13. Department of Orthopaedic Surgery; Akaike Kyodo Clinic; Tagawa-gun Fukuoka Japan
14. Department of Orthopaedic Surgery; Tobata General Hospital; Kitakyushu Japan
15. Department of Orthopaedic Surgery; Kure-Nakadori Hospital; Kure Japan
16. Department of Orthopaedic Surgery, School of Medicine; University of Occupational and Environmental Health; Kitakyushu Japan