[1] Queen Elizabeth Hosp, Dept Surg, Birmingham, England
[2] St Georges Univ Hosp, Dept Orthopaed, London, England
[3] Nottingham Univ Hosp NHS Fdn Trust, Nottingham, England
[4] Poznan Univ Med Sci, Ctr Med Educ English, Poznan, Poland
[5] Countess Chester Hosp NHS Fdn Trust, Chester, England
[6] St Georges Univ, St Georges, West Indies, Grenada
[7] Jorge Voto Bernales Corpancho Hosp, Seguro Social Salud ESSALUD, Lima, Peru
[8] Univ Oxford, Kellogg Coll, Oxford, England