1. University of Bristol, Bristol Implant Research Centre, Avon, Orthopaedic Centre Southmead Hospital, Westbury-on-Trym, Bristol BS10 5NB, UK.
2. Nuffield Department of Orthopaedic Surgery University of Oxford, Nuffield Orthopaedic Centre, Windmill Road, Headington, Oxford OX3 7LD, UK.
3. University of the West of England, Academic Rheumatology Unit Bristol Royal Infirmary, Marlborough Street, Bristol, BS2 8HW, UK.