Effects of Using High‐Frequency TENS During an Exercise Therapy Program in Knee Osteoarthritis: A Randomized Sham‐Controlled Trial.

BACKGROUND AND PURPOSE: Therapeutic exercise is central to knee osteoarthritis (KOA) management, but movement-evoked pain may limit adherence and outcomes. High-frequency transcutaneous electrical nerve stimulation may reduce pain during movement and enhance exercise-related outcomes. This study evaluated whether high-frequency transcutaneous electrical nerve stimulation applied during an exercise therapy program provides additional benefits over sham stimulation in individuals with KOA. METHODS: In this randomized, sham-controlled superiority trial with intended participant blinding and blinded outcome assessment, 96 individuals with KOA were randomized to exercise therapy plus active high-frequency transcutaneous electrical nerve stimulation or exercise therapy plus sham transcutaneous electrical nerve stimulation. The primary outcome was the Knee Injury and Osteoarthritis Outcome Score Pain subscale. Secondary outcomes included the remaining Knee Injury and Osteoarthritis Outcome Score subscales, pain intensity, pain-related self-efficacy, patient-specific function, disability, quadriceps isometric strength, and physical function. Outcomes were assessed at baseline, post-intervention, and 1 month follow-up. Linear mixed models were used for analysis. RESULTS: Active high-frequency transcutaneous electrical nerve stimulation did not provide additional benefit over sham stimulation for the Knee Injury and Osteoarthritis Outcome Score Pain subscale at post-intervention (adjusted mean difference, 1.05 points; 95% CI, -5.19 to 7.29) or at 1 month follow-up (0.40 points; 95% CI, -5.91 to 6.71). These confidence intervals did not reach the predefined 10-point minimal clinically important difference. No statistically significant between-group differences were observed for any secondary outcome. No adverse effects were reported. DISCUSSION: Adding high-frequency transcutaneous electrical nerve stimulation to a structured exercise therapy program did not confer additional benefits over sham stimulation in individuals with KOA. These findings should be interpreted in light of the absence of formal blinding assessment, the short follow-up, and the absence of an exercise-only group. TRIAL REGISTRATION: This trial was registered at ClinicalTrials.gov on December 14, 2023, under the identifier NCT06184451.