1. Department of Orthopaedic Surgery Osaka University Graduate School of Medicine 2‐2 Yamadaoka Suita Osaka 565‐0871 Japan
2. Department of Orthopaedic Surgery Japanese Red Cross Society Himeji Hospital 1‐12‐1 Shimoteno Himeji Hyogo 670‐8540 Japan
3. Department of Orthopaedic Surgery Hoshigaoka Medical Center 4‐8‐1 Hoshigaoka Hirakata Osaka 573‐8511 Japan
4. Department of Rheumatology National Hospital Organization Osaka Minami Medical Center 2‐1 Kidohigashi Kawachinagano Osaka 586‐8521 Japan
5. Department of Orthopaedic Surgery North Osaka Police Hospital 1‐2‐2 Muroyama Ibaraki Osaka 567‐0052 Japan