Effectiveness of transcranial direct current stimulation on pain and function in knee osteoarthritis: a systematic review with meta-analysis based on PRISMA guidelines

Abstract

IntroductionTo evaluate the effectiveness of transcranial direct current stimulation (tDCS) on pain and quality of life in patients with knee osteoarthritis (OA).MethodsThe meta-analysis data source were PubMed (MEDLINE) and Cochrane (Central). Randomized controlled trials comparing active tDCS (in combination with other interventions or alone in knee OA patients) with sham tDCS published in English till July 2019 were analysed. The outcome measures were pain intensity (visual analogue scale and numeric rating scale) and quality of life (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC]). Mean difference with 95% confidence interval for the active tDCS and sham groups were investigated.ResultsFour articles with 171 patients were included in the qualitative systematic review and 2 articles with 55 patients were included in the quantitative meta-analysis. The results revealed a statistically significant reduction in pain (visual analogue scale) in the active tDCS group compared with the sham group (<i>Z</i> = 7.32, <i>p</i> < 0.00001) and a significant improvement in WOMAC scores (<i>Z</i> = 2.31, <i>p</i> = 0.02), with high heterogeneity of 83%.ConclusionsThere is a significant improvement in pain and function in patients with knee OA after the application of active tDCS either alone or in combination. However, more studies are required to confirm the effectiveness of tDCS in knee OA. Owing to the promising results of tDCS in various pain conditions and in knee OA, it can be seen as a future tool for managing pain in the field of physiotherapy.