1. Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada.
2. Division of Orthopaedic Surgery, Department of Surgery, McMaster University, Hamilton, Ontario, Canada.
3. Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada.
4. Department of Orthopaedics, Sahlgrenska University Hospital, Mölndal, Sweden.