Department of Orthopaedic Surgery, School of Medicine, Keio University, Tokyo, Japan.Kusanagi Orthopaedic & Rheumatologic Clinic, Shizuoka, Japan.Kusanagi Orthopaedic & Rheumatologic Clinic, Shizuoka, Japan.Kusanagi Orthopaedic & Rheumatologic Clinic, Shizuoka, Japan.