1. Department of Orthopaedic Surgery; Walter Reed National Military Medical Center; Bethesda Maryland
2. Clinical and Experimental Orthopaedics group; National Institutes of Arthritis and Musculoskeletal and Skin Diseases; National Institutes of Health; Bethesda Maryland
3. Department of Surgery; Brigham and Women's Hospital; Boston Massachusetts
4. Department of Surgery; Uniformed Services University of the Health Sciences; Bethesda Maryland