1. Institute of Orthopaedics and Musculoskeletal Science, University College London, RNOH, Brockley Hill, Stanmore, U.K.
2. Institute of Bioengineering, School of Engineering and Materials Science, Queen Mary, University of London, Mile End Road, London, U.K.
3. Department of Trauma and Orthopaedics, Lister Hospital, East and North Hertfordshire NHS Trust, Coreys Mill Lane, Stevenage, Hertfordshire, U.K.