1. Department of Orthopaedic Surgery, Center for Joint Diseases and Rheumatism, Kyung Hee University Hospital at Gangdong, 892 Dongnam-ro, Gangdong-gu, Seoul 134-727, Korea.
2. Department of Orthopaedic Surgery, Kyung Hee University Hospital, 1 Hoegi-dong, Dongdaemun-gu, Seoul 130-702, Korea.