1. Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Seongnam, Korea.
2. Department of Orthopaedic Surgery, Chung-Ang University College of Medicine, Seoul, Korea.
3. Complex disease and Genome Epidemiology Branch, Department of Public Health Science, School of Public Health, Seoul National University, Seoul, Korea.
4. Department of Orthopaedic Surgery, Seoul National University College of Medicine, Seoul, Korea.