1. Center for Lower Extremity Ambulatory Research, the Dr. William M. Scholl College of Podiatric Medicine at Rosalind Franklin University of Medicine, Chicago, Illinois
2. Department of Surgery, Southern Arizona Veterans Affairs Medical Center, Tucson, Arizona
3. Department of Medicine, Manchester Royal Infirmary, University of Manchester, Manchester, U.K
4. Department of Surgery, Texas A&M University, Temple, Texas