The primary objective of this review was to determine the efficacy of transcutaneous electrical nerve stimulation (TENS) in reducing pain in patients with knee osteoarthritis. The secondary objective was to assess its impact on physical function.
This systematic review and meta-analysis have been registered in PROSPERO (CRD42024579013). In August 2024, the researchers conducted a comprehensive literature search in Embase, Web of Science, PubMed, Scopus, PEDro, and CNKI to identify randomized controlled trials (RCTs) of transcutaneous electrical nerve stimulation (TENS) for the treatment of knee osteoarthritis (KOA). Two reviewers independently assessed eligibility. Means and standard deviations for primary and secondary outcomes were extracted from the included trials and pooled where possible to calculate standardized mean differences (SMDs). Confidence in the results was evaluated using the PEDro scale (Physiotherapy Evidence Database). Study quality was assessed using the Cochrane Collaboration's Risk of Bias tool. Results were presented using means and standard deviations (SD) to calculate SMDs and 95% confidence intervals (CIs). Subgroup and sensitivity analyses were also performed, and publication bias was assessed using the Egger test and funnel plots.
A total of 21 trials were included. Our findings suggest that combined TENS is more effective than conventional treatment for pain [MD: -0.82, 95% CI (-1.01, -0.62), I² = 77%, P 0.001] and muscle strength [MD: 7.39, 95% CI (0.91, 13.88), I² = 0%, P = 0.03]. For the 6-Minute Walk Test (6MWT) [MD: 3.42, 95% CI (-7.72, 14.57), I² = 95%, P = 0.55], McMaster Universities Osteoarthritis Index (WOMAC) [MD: -0.44, 95% CI (-4.69, 3.82), I² = 78%, P = 0.84], and Range of Motion (ROM) [MD: 1.19, 95% CI (-2.09, 4.48), I² = 0%, P = 0.48], the improvements were nonsignificant. No serious adverse events related to TENS were reported.
TENS is effective in reducing pain and increasing knee extensor strength in patients with KOA. TENS may be superior to conventional treatment in reducing KOA pain after two weeks; however, its long-term efficacy requires careful consideration of evidence-based results. TENS appears to be safe for patients with KOA, but clinicians should inform patients of the potential risks of TENS-related adverse events. More well-designed RCTs on this topic are needed in the future.
The results of this review should guide future guidelines and clinical practice. As a non-invasive and safe intervention, TENS encourages patient self-management and can be used in conjunction with other treatments to enhance overall treatment outcomes.
Transcutaneous electrical nerve stimulation
Meta-analysis
