1. Department of Rehabilitation, Walter Reed National Military Medical Center , Bethesda, MD 20814, USA
2. Uniformed Services University of the Health Sciences , Bethesda, MD 20814, USA
3. Department of Orthopaedic Surgery, Walter Reed National Military Medical Center , Bethesda, MD 20814, USA
4. The Center for Rehabilitation Sciences Research, Department of Physical Medicine & Rehabilitation, Uniformed Services University of Health Sciences , Bethesda, MD 20814, USA
5. The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc. , Bethesda, MD 20817, USA