1 1Canterbury Christ Church University, Faculty of Health and Social Sciences, 30 Pembroke Court, Chatham Maritime, Kent, ME4 4UF United Kingdom.
2 2Kent Knee Unit, Spire Alexandra Hospital, Impton lane, Chatham, Kent, ME5 9PG United Kingdom.
3 3Department of Orthopedic Surgery, Uijeongbu St. Mary's Hospital, College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul, 137-701 Republic of Korea.
4 5Department of Orthopaedics, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria.