1. Division of Orthopaedic Surgery, Department of Surgery, University of Toronto, Toronto, Ontario, Canada
2. Division of Orthopaedic Surgery, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
3. Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada
4. Department of Anesthesia, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
5. Department of Medicine, University of Toronto, Toronto, Ontario, Canada