Subgrouping and targeted exercise programmes for knee and hip osteoarthritis (STEER OA) individual participant data meta-analysis. Progress update and selection of potential moderators for analyses. (April 2019) - Holden, M.A.; Runhaar, J.; Burke, D.L.; van Der Windt, D.; Riley, R.D.; Dziedzic, K.; Legha, A.; Quicke, J.G.; Healey, E.L.; Bourton, A.L.; Bierma-Zeinstra, S.; Abbott, J.H.; et al.