1. Northumbria NHS, Foundation Trust, Northumbria Healthcare, NE63 9JJ, UK
2. Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK
3. Trauma Unit, Kadoorie Centre, Level 3, John Radcliffe Hospital, Oxford, OX3 9DU, UK
4. Oxford University Hospitals NHS Foundation Trust, Headley Way, Oxford, OX3 9DU and Oxford Trauma, Nuffield Department of Rheumatology Orthopaedics and Musculoskeletal Science, University of Oxford, OX3 9DU, UK
5. University of Newcastle, and Northumbria Healthcare, Northumberland, NE63 9JJ, UK