1 Trauma and Orthopaedic Department, University College London Hospitals NHS Foundation Trust, 250 Euston Road, London NW1 2PG, United Kingdom. Electronic address: aymangabr@hotmail.co.uk.
2 The Royal Berkshire NHS Foundation Trust, United Kingdom.
3 University Hospitals Coventry and Warwickshire NHS Trust, United Kingdom.
4 Bradford Teaching Hospitals NHS Foundation Trust, United Kingdom.
5 University College London Hospitals NHS Foundation Trust, London, United Kingdom.