Department of Orthopedic Surgery, Seoul National University College of Medicine, Seoul, Korea.
Address reprint request to Young-Min Kim, MD. Department of Orthopedic Surgery, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul 110-744, Korea. TEL: +82-2-2072-2368, FAX: +82-2-764-2718, hipkim@korea.com
Received 25 February 2012 Revised 21 March 2012 Accepted 21 March 2012