1. Medical Engineering Division, School of Engineering and Materials Science, Queen Mary, University of London, Mile End Road, London E1 4NS, UK
2. Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Leahurst Campus, Neston CH64 7TE, UK
3. Institute of Orthopaedics and Musculoskeletal Science, University College London, Stanmore HA7 4LP, UK