1 Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Arthritis Research UK Centre for Sport, Exercise and Osteoarthritis, Oxford, United Kingdom of Great Britain and Northern Ireland.
2 British Horseracing Authority Ltd, Medical, London, United Kingdom of Great Britain and Northern Ireland.
3 Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom of Great Britain and Northern Ireland.
4 Department of Health, University of Bath, Bath, United Kingdom of Great Britain and Northern Ireland.
5 Department of Primary Care and Population Health, Institute of Epidemiology and Health Care, University College London, London, United Kingdom of Great Britain and Northern Ireland.