1. Pilgrim Hospital, Department of Trauma and Orthopaedics, Sibsey Road, Boston, Lincolnshire PE21 9QS, UK.
2. Cheltenham General Hospital, Department of Trauma and Orthopaedics, Sandford Road, Cheltenham, Gloucestershire GL53 7AN, UK.
3. Southern General Hospital, Department of Orthopaedics, 1345 Govan Road, Glasgow G51 4TF, UK.
4. Leicester Royal Infirmary, Department of Orthopaedics, Infirmary Square, Leicester LE1 5WW, UK.