Affiliation: | 1. Department of Orthopaedics, Countess of Chester Hospital NHS Trust, Liverpool Road, Chester CH2 1UL, UK;2. Department of Orthopaedics, Royal Liverpool University Hospital, Prescot Street, Liverpool L7 8XP, UK;3. Department of Orthopaedics, Wirral University Hospitals NHS Trust, Arrowe Park Road, Upton, Wirral CH49 5PE, UK |