1. Temerty Faculty of Medicine University of Toronto Toronto Ontario Canada
2. Biostatistics Division, Dalla Lana School of Public Health University of Toronto Toronto Ontario Canada
3. Division of Orthopaedic Surgery McGill University Montréal Québec Canada
4. Division of Orthopaedic Surgery McMaster University Hamilton Ontario Canada
5. Department of Orthopaedics, University of Maryland School of Medicine University of Maryland Baltimore Maryland USA
6. Department of Epidemiology and Biostatistics McGill University Montréal Québec Canada