1. University of Oxford, Nuffield Department of Orthopaedics, Rheumatology & Musculoskeletal Sciences, University of Oxford, Botnar Research Centre, Windmill Road, Headington, Oxford OX3 7LD, UK.
2. University of Oxford, Nuffield Department
of Population Health, Old Road Campus, Headington, Oxford
OX3 7LF, UK.
3. University of Aberdeen, Centre for
Healthcare Randomised Trials, Health Services
Research Unit, Foresterhill, Aberdeen
AB25 2ZD, UK.