1. Statistics and Epidemiology Unit, Warwick Medical School, University of Warwick, Coventry, UK.
2. Sir Charles Gairdner Hospital and The University of Western Australia, Nedlands, Perth, Australia.
3. Oxford Clinical Trials Research Unit, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK.
4. Oxford Trauma, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK.
5. Department of Trauma and Orthopaedic Surgery, Centre for Clinical Research, Unfallkrankenhaus Berlin, Berlin, Germany.