1. Department Orthopaedic Surgery, Sapporo Medical University School of Medicine, Sapporo, Hokkaido, Japan
2. Division of Radiology and Nuclear Medicine, Sapporo Medical University Hospital, Sapporo, Hokkaido, Japan
3. Department of Orthopaedic Surgery, Sapporo Maruyama Orthopaedic Hospital, Sapporo, Hokkaido, Japan