1. Department of Orthopaedics, Los Angeles County-University of Southern California Medical Center, 1200 N. State Street, GNH 3900, Los Angeles, CA 90033, USA
2. University of Southern California, Keck School of Medicine, Los Angeles County-University of Southern California Medical Center, 1200 N. State Street, GNH 3900, Los Angeles, CA 90033, USA
3. University of Southern California, Keck School of Medicine, USC University Hospital, 1510 San Pablo Street, Suite 634, Los Angeles, CA 90033-4608, USA