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.