1Musculosketal Research Unit, School of Clinical Sciences, University of Bristol, Avon Orthopaedic Centre, Bristol BS10 5NB, UK
2Peninsula Medical School, Universities of Plymouth and Exeter, University of Exeter, Exeter EX1 2LU
3Centre for Hip Surgery, Wrightington Hospital, Wigan, Lancashire WN6 9EP
4Musculoskeletal Research Unit (MRU)