1. Department of Orthopaedic Surgery, Gunma University Graduate School of Medicine, Gunma, Japan;
2. Department of Rheumatology, Isesaki Fukushima Hospital, Gunma, Japan;
3. Department of Orthopaedic Surgery, Inoue Hospital, Gunma, Japan;
4. Department of Orthopaedic Surgery, Japan Redcross Society Fukaya Redcross Hospital, Saitama, Japan;
5. Department of Orthopaedic Surgery, Keiyu Orthopaedic Hospital, Gunma, Japan