1. Imperial College NHS Trust/St Mary’s and Charing Cross Hospitals, Praed Street, London W2 1NY, UK.
2. Hopital de al Croix-Rousse, 103 Grande-Rue de la Croix Rousse, 69317 Lyon, France.
3. Chelsea and Westminster Hospital, 369 Fulham Road, London SW10 9NH, UK.
4. Department of Mechanical Engineering and Musculoskeletal Surgery, Imperial College London, London SW7 2AZ, UK.