1. Center of Artificial Joint and Rheumatism, Fukuoka Tokushukai Medical Center, Fukuoka, Japan
2. Department of Orthopaedic Surgery, School of Medicine, University of Occupational and Environmental Health, Fukuoka, Japan
3. Department of Orthopaedic Surgery, School of Medicine, Kyung Hee University, Seoul, Korea
4. Japan Research Institute of Artificial Joint, Kisarazu, Japan