1. Department of Orthopaedic Surgery, Kyung Hee University School of Medicine, #1 Hoeki-dong, Dongdaemun-Ku, Seoul 130-702, Korea.
2. Department of Orthopaedic Surgery, Kang Nam General Hospital, #171-1 Samsung-dong, Kangnam-Ku, Seoul 135-091, Korea.
3. Department of Orthopaedic Surgery, Pochon CHA University School of Medicine, #351 Yatap-dong, Bungdang-Ku, Sungnam, Gyeonggi-do 463-070, Korea