1. Warwick Clinical Trials Unit, University of Warwick, Coventry, UK
2. Health Economics Research Group, Brunel University, Uxbridge, UK
3. Faculty of Health Sciences, University of Southampton, Southampton, UK
4. University College London, London, UK
5. Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK