Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ; Anesthesiology, Johns Hopkins University, Baltimore, MD; Statistics, Rutgers University, New Brunswick, NJ; Medicine, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ; Medicine, Saint Louis University, Saint Louis, MO; Departments of Physical Therapy and Surgery (Division of Orthopaedic Surgery), University of Alberta, Edmonton, Canada; Department of Orthopedic Surgery, Columbia University, New York, NY; Rutgers University School of Public Health, Piscataway, NJ; University of Pennsylvania, Philadelphia, PA; Medicine, University of Calgary, Calgary, AB, Canada; Surgeons Surgery Center, Cumberland, MD; Maimonides Medical Center, Brooklyn, NY; Department of Epidemiology, University of Maryland, Baltimore