H K James1, A W Chapman2, G T R Pattison2, D R Griffin3, J D Fisher1. 1. Clinical Trials Unit, University of Warwick, Coventry, UK. 2. Deaprtment of Trauma and Orthopaedics, University Hospitals Coventry and Warwickshire, Coventry, UK. 3. Warwick Orthopaedics, Warwick Medical School, University of Warwick, Coventry, UK.