1. Trauma and Orthopaedics, The Birmingham Orthopaedic Network, The Royal Orthopaedic Hospital, Birmingham B31 2AP, UK
2. College of Medical and Dental Sciences, Birmingham Medical School, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
3. Trauma and Orthopaedics Department, University Hospitals Birmingham NHS Foundation Trust, Queen Elizabeth Hospital, Birmingham B15 2GW, UK