Melanie A Holden, Danielle L Burke, Jos Runhaar, Danielle van Der Windt, Richard D Riley, Krysia Dziedzic, Amardeep Legha, Amy L Evans, J Haxby Abbott, Kristin Baker, Jenny Brown, Kim L Bennell, Daniël Bossen, Lucie Brosseau, Kanda Chaipinyo, Robin Christensen, Tom Cochrane, Mariette de Rooij, Michael Doherty, Helen P French, Sheila Hickson, Rana S Hinman, Marijke Hopman-Rock, Michael V Hurley, Carol Ingram, Jesper Knoop, Inga Krauss, Chris McCarthy, Stephen P Messier, Donald L Patrick, Nilay Sahin, Laura A Talbot, Robert Taylor, Carolien H Teirlinck, Marienke van Middelkoop, Christine Walker, Nadine E Foster

Knee and hip osteoarthritis (OA) is a leading cause of disability worldwide. Therapeutic exercise is a recommended core treatment for people with knee and hip OA, however, the observed effect sizes for reducing pain and improving physical function are small to moderate. This may be due to insufficient targeting of exercise to subgroups of people who are most likely to respond and/or suboptimal content of exercise programmes. This study aims to identify: (1) subgroups of people with knee and hip OA that do/do not respond to therapeutic exercise and to different types of exercise and (2) mediators of the effect of therapeutic exercise for reducing pain and improving physical function. This will enable optimal targeting and refining the content of future exercise interventions. Systematic review and individual participant data meta-analyses. A previous comprehensive systematic review will be updated to identify randomised controlled trials that compare the effects of therapeutic exercise for people with knee and hip OA on pain and physical function to a non-exercise control. Lead authors of eligible trials will be invited to share individual participant data. Trial-level and participant-level characteristics (for baseline variables and outcomes) of included studies will be summarised. Meta-analyses will use a two-stage approach, where effect estimates are obtained for each trial and then synthesised using a random effects model (to account for heterogeneity). All analyses will be on an intention-to-treat principle and all summary meta-analysis estimates will be reported as standardised mean differences with 95% CI. Research ethical or governance approval is exempt as no new data are being collected and no identifiable participant information will be shared. Findings will be disseminated via national and international conferences, publication in peer-reviewed journals and summaries posted on websites accessed by the public and clinicians. CRD42017054049.