1. Hokushin Orthopaedic Hospital, Kikusuimotomachi 3-3, Shiroishi-ku, 003-0823, Sapporo, Japan.
2. Department of Sports Medicine and Joint Reconstruction Surgery
3. Department of Orthopaedic Surgery, Hokkaido University Graduate School of Medicine, Kita-15 Nishi-7 Kita-ku, 060-8638, Sapporo, Japan.