1. Department of Orthopedic Surgery, George Washington School of Medicine and Health Sciences, Washington, District of Columbia
2. Department of Orthopedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
3. Department of Orthopaedic Surgery, The Stavros Niarchos Foundation Complex Joint Reconstruction Center, Hospital for Special Surgery, New York, New York
4. Department of Orthopaedic Surgery, Columbia University Vagelos College of Physicians and Surgeons, New York, New York