1. Department of Medical Engineering, National Defense Medical College, Tokorozawa, Saitama, Japan.
2. Department of Orthopaedic Surgery, Surgical Science, Tokai University School of Medicine, Isehara, Kanagawa, Japan.
3. National Defense Medical College Research Institute, Tokorozawa, Saitama, Japan.
4. Department of Orthopaedic Surgery, National Defense Medical College, Tokorozawa, Saitama, Japan.