1. Centre for Spinal Studies and Surgery, Queen’s Medical Centre, Nottingham NG7 2UH, UK.
2. Department of Trauma and Orthopaedic Surgery, Northern General Hospital, Herries Road, Sheffield S5 7AU, UK.
3. Nottingham Shoulder and Elbow Unit, Nottingham City Hospital, Hucknall Road, Nottingham NG5 1PB, UK.