[1] Univ Oxford, Botnar Res Ctr, NDORMS, Oxford OX3 7LD, England
[2] Univ Oxford, NDORMS, Ctr Stat Med, Oxford, England
[3] Oxford Univ Hosp NHS Fdn Trust, Oxford, England
[4] Cambridge Univ Hosp NHS Fdn Trust, Cambridge, England
[5] Royal Berkshire NHS Fdn Trust, Reading, Berks, England
[6] Univ Cambridge, Div Trauma & Orthopaed Surg, Cambridge, England
[7] Univ Oxford, NDORMS, Royal Coll, Surg Surg Intervent Trials Unit, Oxford, England
[8] Royal Berkshire NHS Fdn Trust, Reading, Berks, England
[9] Wye Valley NHS Trust, Hereford, England
[10] Weston Area Hlth NHS Trust, Weston Super Mare, England
[11] Great Western Hosp NHS Fdn Trust, Swindon, Wilts, England
[12] Harrogate & Dist NHS Fdn Trust, Harrogate, England