1. Department of Orthopaedic and Trauma Research, Tokyo Medical and Dental University, Tokyo, Japan
2. Department of Orthopaedics, Tokyo Medical and Dental University, Tokyo, Japan
3. Department of Quality Management Center, Tokyo Medical and Dental University Hospital, Tokyo, Japan
4. Department of Hepato-Biliary-Pancreatic Surgery, Tokyo Medical and Dental University, Tokyo, Japan
5. Department of Health Policy and Informatics Section, Tokyo Medical and Dental University, Tokyo, Japan