1. Department of Orthopaedic Surgery Musgrove Park Hospital, Taunton, Somerset TA1 5DA, UK.
2. Royal United Hospital, Coombe Park, Bath BA1 3NG, UK.
3. Royal Devon and Exeter Hospital, Barrack Road, Exeter EX2 5DW, UK.
4. Avon Orthopaedic Centre Southmead Hospital, Westbury-on-Trym, Bristol BS10 5NB, UK.