1. Academic Department of Trauma and Orthopaedics, School of Medicine, University of Leeds, Clarendon Wing, Floor A, Great George Street, Leeds General Infirmary, Leeds LS1 3EX, UK.
2. Department of Orthopaedic Surgery, Saint Louis University School of Medicine, 3635 Vista Avenue, 7th Floor, Desloge Towers, St Louis, Missouri 63110, USA.