1. Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK
2. Department of Orthopaedic Surgery, Imperial College NHS Healthcare Trust, London, UK
3. Department of Acute Internal Medicine, University College London Hospital NHS Trust, London, UK
4. Department of Orthopaedic Surgery, Barts Health NHS Trust, London, UK
5. Department of Orthopaedic Surgery, Great Ormond Street Hospital, London, UK
6. University College London, London, UK