1. Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada.
2. Division of Orthopaedic Surgery, Department of Surgery, McMaster University Medical Centre, Hamilton, Ontario, Canada.
3. Department of Orthopaedics, Institute of Clinical Sciences, The Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden.
4. Department of Orthopaedics, Sahlgrenska University Hospital, Mölndal, Sweden.
5. Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.