1. University of Manchester, Manchester M13 9PL, UK
2. Institute of Orthpaedics and Musculoskeletal Science, Royal National Orthopaedic Hospital, Stanmore, Middlesex HA7 4LP, UK
3. Spinal Deformity Unit, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, Middlesex HA7 4LP, UK
4. Stepping Hill Hospital, Stockport SK2 7JE, UK
5. Department of Sports Inury, Royal National Orthopaedic Hospital, Birimingham B31 2AP, UK