1. Hull York Medical School, Heslington, York, YO10 5DD, United Kingdom
2. Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, OX3 7LD, United Kingdom
3. Division of Trauma and Orthopaedics, University of Cambridge, Addenbrooke's Hospital, Cambridge, CB2 2QQ, United Kingdom