1. R Adams Cowley Shock Trauma Center, Department of Orthopaedics University of Maryland School of Medicine Baltimore MD USA
2. Division of Orthopaedic Surgery, Department of Surgery McMaster University Hamilton Canada
3. University Orthopaedic Center University of Utah Salt Lake City UT USA
4. Department of Medicine McMaster University Hamilton Canada
5. Department of Health Research Methods, Evidence, and Impact McMaster University Hamilton Canada