[1] Royal Natl Orthopaed Hosp, Joint Reconstruct Unit, London HA7 4LP, England
[2] Imperial Coll London, Dept Surg & Canc, Trauma & Orthopaed Surg, London SW7 2AZ, England
[3] Western Univ, London Hlth Sci Ctr, Rorabeck Bourne Joint Replacement Inst, Schulich Sch Med & Dent, London, ON, Canada
[4] Whittington Hlth NHS Trust, Trauma & Orthopaed Dept, Magdala Ave, London N19 5NF, England
[5] Univ Leeds, Sch Med, Acad Dept Trauma & Orthopaed Surg, Leeds Gen Infirmary, Clarendon Wing,Floor D,Great George St, Leeds LS1 3EX, England
[6] Chapel Allerton Hosp, NIHR Leeds Biomed Res Ctr, Leeds, England