1. Department of Trauma and Orthopaedics, Imperial College School of Medicine, St Mary's Hospital, London, United Kingdom
2. The Hillingdon Hospital, Uxbridge, Middlesex, United Kingdom
3. Department of Orthopaedics and Traumatology, Imperial College School of Medicine, Chelsea and Westminster Hospital, London, United Kingdom
4. Department of Anaesthetics, Imperial College School of Medicine, Chelsea and Westminster Hospital, London, United Kingdom