Effects of Noninvasive Interactive Neurostimulation on Symptoms of Osteoarthritis of the Knee: A Randomized, Sham-Controlled Pilot Study

Abstract

To explore the effects of noninvasive interactive neurostimulation used as an adjunct to usual care, on pain and other symptoms in adults with osteoarthritis of the knee. Randomized, sham-controlled trial. A university in the southern United States. Thirty-seven (37) adults with knee osteoarthritis (based on American College of Rheumatology diagnostic criteria). Seventeen (17) noninvasive interactive neurostimulation (active or sham) sessions over 8 weeks with a week 12 follow-up. Eleven-point numeric rating scale for weekly pain; Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), patient global assessment, and Short-Form Health Survey (SF-36) completed at baseline and weeks 4, 8, and 12. For the main outcome, pain, the differences between the groups over time did not reach statistical significance (all p > 0.05). However, a clinically important reduction in pain (defined as a 2-point or 30% reduction on an 11-point numeric rating scale) was maintained at week 12 by the active noninvasive interactive neurostimulation group (2.17 points, 34.55% reduction) but not the sham group (1.63, 26.04% reduction). Pain improved over time in participants regardless of group membership (numeric rating scale average pain, p = 0.002; numeric rating scale worst pain, p < 0.001; and WOMAC pain, p < 0.001), as did WOMAC function, WOMAC stiffness, and WOMAC total score (all p < 0.001). Repeated measures ANOVA revealed a statistically significant difference between the groups over time for the SF-36 Vitality scale, F (3, 105) = 3.54, p = 0.017. In addition, the active device group improved on the patient global assessment from baseline to week 8 compared to the sham device group, F (1, 35) = 4.025, p = 0.053. In this pilot study, clinically important reductions in knee pain were maintained at week 12 in the active, but not the sham, noninvasive interactive neurostimulation group. Further study of this noninvasive therapy is warranted.