1. Department of Orthopaedic Surgery, South Medical Center, Ogawara 989-1253, Japan
2. Department of Orthopaedic Surgery, Tohoku University School of Medicine, Sendai 980-8574, Japan
3. Department of Orthopaedic Surgery, Obihiro Kosei Hospital, Obihiro 080-0024, Japan
4. Department of Orthopaedic Surgery, Sendai City Hospital, Sendai 982-8502, Japan
5. Department of Diagnostic Radiology, Tohoku University Hospital, Sendai 980-8574, Japan
6. Department of Orthopaedic Surgery, Tohoku Rosai Hospital, Sendai 981-8563, Japan