1. Department of Orthopaedic Surgery; Keio University School of Medicine; 35 Shinanomachi, Shinjyuku-ku Tokyo 160-8582 Japan
2. Department of Orthopaedic Surgery; Fujita Health University; Aichi Japan
3. Section of Electron Microscopy; Showa University; Tokyo Japan
4. Department of Pathology; Tohoku University Graduate School of Medicine; Sendai Japan
5. Department of Molecular Target Medicine; Aichi Medical University School of Medicine; Aichi Japan
6. Department of Orthopaedic Surgery; National Defence Medical College; Saitama Japan