[1] Univ Warwick, Warwick Med Sch, Warwick Clin Trials Unit, Coventry, W Midlands, England
[2] Univ London, Kings Coll London, London, England
[3] Oxford Univ Hosp NHS Fdn Trust, Oxford, England
[4] Univ Oxford, Ctr Stat Med, Nuffield Dept Orthopaed Rheumatol & Musculoskelet, Oxford, England
[5] Univ Oxford, Ctr Rehabil Res Oxford, Nuffield Dept Orthopaed Rheumatol & Musculoskelet, Oxford, England