1. Department of Orthopaedic Surgery, Research Institute of Clinical Medicine, Chonbuk National University Medical School, G34-18 Keumam-dong, Jeonju-shi, 561-712, South Korea.
2. Department of Orthopaedic Surgery David Geffen School of Medicine at UCLA, 1250 16th Street, 7th Floor Tower, No 745, Santa Monica, California 90404, USA.