Effectiveness of Transcranial Direct Current Stimulation in Knee Osteoarthritis: A Systematic Review and Meta-analysis of Randomized Sham-Controlled Trials

Objective The aim of the study is to assess the effectiveness of transcranial direct current stimulation in knee osteoarthritis. Methods The study searched PubMed, Cochrane Library, Embase, and Scopus databases until August 3, 2023, and identified randomized controlled trials evaluating the effects of transcranial direct current stimulation in knee osteoarthritis whose outcomes using pain scores or functional scales. The selected randomized controlled trials were subjected to meta-analysis and risk of bias assessment. Results Seven randomized controlled trials involving 488 patients were included in this meta-analysis. Compared with the control group, the transcranial direct current stimulation group exhibited significant improvement in pain scores after treatment (standardized mean difference = 1.03; 95% confidence interval: 0.70 to 1.35; n = 359; I2 = 46%), pain scores during follow-up (standardized mean difference = 0.83; 95% confidence interval: 0.21 to 1.45; n = 358; I2 = 86%), and Western Ontario and McMaster Universities Osteoarthritis scores after treatment (standardized mean difference = 4.76; 95% confidence interval: 0.16 to 9.53; n = 319; I2 = 74%), but Western Ontario and McMaster Universities Osteoarthritis scores during follow-up did not differ significantly between the groups (standardized mean difference = 0.06; 95% confidence interval: -0.2 to 0.32; n = 225; I2 = 0%). Conclusions Transcranial direct current stimulation is a promising therapy for knee osteoarthritis. Further investigation using large-scale, high-quality randomized controlled trials is necessary for optimal transcranial direct current stimulation approach in knee osteoarthritis. © Wolters Kluwer Health, Inc. All rights reserved.