1. Department of Orthopaedic Surgery, Faculty of Medicine and Graduate School of Medicine Hokkaido University Sapporo, Hokkaido Japan
2. Department of Biostatistics, Graduate School of Medicine Hokkaido University Sapporo, Hokkaido Japan
3. Department of Functional Reconstruction for the Knee Joint Hokkaido University Sapporo, Hokkaido Japan
4. Centre for Sports Medicine, Hokkaido University Hospital Sapporo, Hokkaido Japan