A 3-month, randomized, double-blind, placebo-controlled study to evaluate the safety and efficacy of a highly optimized, capacitively coupled, pulsed electrical stimulator in patients with osteoarthritis of the knee.

Objective: To investigate the efficacy and safety of a capacitively coupled, pulsed electrical stimulation device in treating knee osteoarthritis (OA).

Design: Fifty-eight outpatients with moderate to severe OA of the knee entered a 3-month, double-blind, placebo-controlled trial, using either an active or placebo device at home for 6 to 14 h/day. Outcome measures included a patient global evaluation, a patient report of knee pain severity, and the Western Ontario and McMaster Universities (WOMAC) questionnaire.

Results: Active treatment provided superior outcomes between baseline and 3-month follow-up measurements: 50.6% greater improvement than placebo in patient global (P=0.03), 31.2% in patient pain (P=0.04), 25.1% in WOMAC stiffness (P=0.03), 29.5% in WOMAC function (P=0.01), 19.9% in WOMAC pain (P=0.11), and 27% in total WOMAC (P=0.01). The percent of patients who improved by more than 50% was 38.5 active vs 5.3 placebo in patient global (P=0.01), 43.6 vs 15.8 in patient pain (P=0.04), 38.5 vs 10.5 in WOMAC pain (P=0.03), 28.2 vs 5.3 in WOMAC stiffness (P=0.08), 23.1 vs 5.3 in WOMAC function (P=0.14), and 23.1 vs 5.3 in total WOMAC (P=0.14). Twenty-one percent of placebo and 18% of actively treated patients developed a transient rash at the electrode sites. No other adverse device effects were reported.

Conclusion: A highly optimized, capacitively coupled, pulsed electrical stimulus device significantly improved symptoms and function in knee OA without causing any serious side effects.