Efficacy and safety of different topical diclofenac formulations for the treatment of knee osteoarthritis: a meta-analysis of short-term and long-term treatment comparisons

ObjectiveThis meta-analysis evaluates the efficacy and safety of various topical dosage forms of diclofenac (gel, solution, and patch) for the treatment of knee osteoarthritis.MethodsA comprehensive literature search was conducted in PubMed, Embase, Cochrane Library, and Web of Science for randomized controlled trials evaluating topical diclofenac formulations in knee osteoarthritis patients. Data on pain relief, functional outcomes, and adverse events were extracted. The primary outcomes were pain and function scores at different follow-up intervals (1-2 weeks, 3-6 weeks, 8-12 weeks), and safety outcomes.ResultsA total of 12 randomized controlled trials (RCTs) were included in the analysis. Diclofenac gel, solution, and patch were all shown to significantly alleviate pain and improve function in patients with knee osteoarthritis. At 1-2 weeks, the diclofenac patch delivered the most pronounced short-term pain relief (SMD: -0.64; 95% CI: -0.90 to -0.39), while the gel and solution demonstrated sustained efficacy over the mid-term (3-6 weeks) and long-term (8-12 weeks). whereas skin-related adverse events, systemic side effects and withdrawal rates remained low across all formulations. The overall quality of evidence was assessed as moderate to high, reinforcing the robustness of the findings.ConclusionsTopical diclofenac formulations (gel, solution, patch) significantly improve pain and function in knee osteoarthritis compared to placebo. All formulations were well-tolerated, with no significant increase in adverse events. These findings support the use of topical diclofenac for short-term pain relief and functional improvement in KOA patients.