Usefulness and Safety of a Wearable Transcutaneous Electrical Nerve Stimulation Device for Promoting Exercise Therapy in Patients With Chronic Knee Pain: A Randomized Controlled Trial.

Objective: To investigate the effect of transcutaneous electrical nerve stimulation (TENS) in reducing barriers to the implementation of exercise therapy and promoting exercise therapy, focusing on physical activity (PA).

Design: A single-center, participant-blinded, randomized controlled trial with a pre-post design.

Setting: Orthopedic clinic at a single institution,.

Participants: Participants (N=63, aged ≥50y) who had knee pain for ≥3 months were randomly assigned to the TENS (N=21), exercise (N=23), or combined (N=19) groups.

Interventions: Participants were provided with 4 weeks of intervention: the TENS group using a wearable TENS device, exercise group performing designated exercises, and combined group performing activities from the TENS and exercise groups.

Main Outcome Measures: The primary outcome measure was PA. The secondary outcome measures were 6-minute walk test (6MWT); timed Up and Go (TUG) test; stair climbing; knee pain using the visual analog scale at 6MWT, TUG test, and stair climbing; and patient-reported changes in knee pain over time.

Results: At pre- and postintervention, light-intensity PA time (minutes per day) in the TENS, exercise, and combined groups was 735.62±68.82 vs 714.21±73.06 (P=.061), 733.05±103.90 vs 700.31±90.33 (P=.057), and 710.09±62.98 vs 685.22±58.35 (P=.049), respectively, with a significant decrease in the combined group. Significant improvement in knee pain and stair climbing was observed in all groups pre- and postintervention.

Conclusions: The group using TENS showed improved effects of early reduction in knee pain and when combined with exercise therapy, a reduction in time spent in light-intensity activities such as sedentary behavior. Thus, the use of TENS in combination with conventional exercise therapy has the potential to reduce psychological barriers to the introduction of exercise therapy. It also promotes and ensures the safe implementation and continuation of exercise therapy.