Efficacy and safety of aquatic exercise in knee osteoarthritis: A systematic review and meta-analysis of randomized controlled trials

Objective To examine the efficacy and safety of aquatic exercise for people with knee osteoarthritis. Data sources PubMed, Web of Science, Embase, CENTRAL, CNKI and WanFang databases were searched from 1966 to September 2022. Review methods Randomized controlled trials evaluating aquatic exercise for people with knee osteoarthritis compared with no exercise and land-based exercise were included. The Grading of Recommendations Assessment, Development and Evaluation system was used to evaluate the certainty of evidence. Results Twenty-two studies with 1394 participants were included. Compared with no exercise (13 trials with 746 participants), low-to high-certainty evidence revealed that aquatic exercise yielded significant improvements in patient-reported pain (SMD −0.58, 95% CI −0.82 to −0.33), stiffness (SMD −0.57, 95% CI −1.03 to −0.11) and physical function (SMD −0.35, 95% CI −0.52 to −0.18) immediately postintervention. A sustained effect was observed only for pain at three months postintervention (SMD −0.48, 95% CI −0.91 to −0.06). The confidence intervals demonstrated that the pooled results do not exclude the minimal clinically important differences. There were no significant differences between the effects of aquatic exercise and land-based exercise (13 trials with 648 participants) on pain (SMD −0.12, 95% CI −0.29 to 0.04), stiffness (SMD −0.17, 95% CI −0.49 to 0.16) or physical function (SMD −0.13, 95% CI −0.28 to 0.02). No study reported a serious adverse event in relation to aquatic exercise. Conclusion Aquatic exercise provides a short-term clinical benefit that is sustained for at least three months postintervention in terms of pain in people with knee osteoarthritis.