Effect of exercise therapy in patients with hip osteoarthritis: A systematic review and cumulative meta-analysis

Objective: To evaluate the existing evidence on the effect of exercise therapy in patients with hip osteoarthritis (OA) compared to no treatment and explore whether a further trial will change the current evidence. Design: Systematic review and cumulative meta-analysis using randomized controlled trials (RCT) to determine the effect on pain and function post-treatment, and at 6-9 months after treatment. Standardized mean difference (SMD) <= -0.37 was considered clinically worthwhile. Extended funnel plots were used to simulate the impact of a new trial on the pooled effect size of pain and function. Results: 18 RCTs were included. Post-treatment we found a beneficial effect of exercise therapy on pain (SMD -0.38, 95% Confidence Interval (CI): 0.55 to -0.22) and function (SMD -0.31, 95% CI -0.49 to -0.11). A beneficial effect of exercise therapy on pain (SMD -0.23, 95% CI: 0.41 to -0.05) and function (SMD -0.29, 95% CI: 0.45 to -0.12) was found 6-9 months after treatment. Most effect estimates were small, and it is unclear whether these are clinically meaningful. Extended funnel plots and a simulation of a new trial showed that only a new trial with a larger effect than the current pooled effect or a trial including 74,843 participants would change the pooled effect estimate from an unclear to a clearly clinically worthwhile effect. Conclusions: We found a beneficial effect of exercise therapy on pain and function in hip OA. It is unlikely a new trial added to current evidence will change the conclusion.