1 Consultant Trauma and Orthopaedic Surgeon, Department of Trauma and Orthopaedics, University College London Hospitals NHS Trust, London NW1 2BU.
2 Consultant Musculoskeletal Radiologist, Department of Musculoskeletal Radiology, Oxford University Hospitals NHS Foundation Trust Nuffield Orthopaedic Centre, University of Oxford, Oxford.
3 Consultant Orthopaedic and Trauma Surgeon, Department of Trauma and Orthopaedics, The Ottawa Hospital, Ottawa, Ontario, Canada.