1. Department of Orthopaedic Surgery, Walter Reed National Military Medical Center, Bethesda, Maryland
2. Department of Orthopaedic Surgery, 96th Medical Group US Air Force Eglin Regional Hospital, Eglin AFB, Florida
3. School of Public Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland
4. Department of Orthopedics, Walter Reed Army Medical Center, Bethesda, Maryland
5. Department of Orthopaedics, Walter Reed National Military Medical Center, Bethesda, Maryland