1. Division of Rheumatology, Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
2. Department of Orthopaedic Surgery, University of Virginia School of Medicine, Charlottesville, VA, USA.
3. Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.