1. Academic Department of Trauma & Orthopaedics, School of Medicine, University of Leeds, Leeds LS2 9LU, UK
2. Trauma Audit and Research Network, Summerfield House, Salford Royal NHS Foundation Trust, Salford M6 8HD, UK
3. Centre for Urgent and Emergency Care Research, School of Health and Related Research (ScHARR), University of Sheffield, Sheffield S1 4DA, UK
4. NIHR Leeds Biomedical Research Centre, Chapel Allerton Hospital, Leeds LS2 9LU, UK