1. Department of Orthopaedic SurgeryOsaka University Graduate School of Medicine 2‐2 Yamadaoka Suita Osaka Japan
2. Department of Orthopaedic SurgeryToyonaka Municipal Hospital Toyonaka Osaka Japan
3. Department of Orthopaedic Biomaterial ScienceOsaka University Graduate School of Medicine 2‐2 Yamadaoka Suita Osaka 565‐0871 Japan