1. Nuffield Department of Orthopaedics Rheumatology and Musculoskeletal Sciences (NDORMS), University of Oxford, Nuffield Orthopaedic Centre, Windmill Road, Oxford OX3 7HE, UK
2. CURE Children’s Hospital of Ethiopia, P.O. Box 21634, Addis Ababa 1000, Ethiopia
3. International Centre for Evidence in Disability, Department of Population Health, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
4. Division of Physiotherapy, Department of Health and Rehabilitation Sciences, Stellenbosch University, Cape Town 7602, South Africa