Pulsed electrical stimulation in patients with osteoarthritis of the knee: follow up in 288 patients who had failed non-operative therapy.

BACKGROUND: Optimized pulsed electrical stimulation (PES) regulates chondrocyte genes, enhances production of cartilage matrix materials, and inhibits production of matrix catabolic factors. METHODS: This prospective, cohort study examined the use of a PES device in treatment of knee osteoarthritis (OA) in patients who had failed non-operative therapy. Primary outcome measures were patient and physician global evaluation, and patient assessment of knee pain. RESULTS: This study included 288 (95 men, 193 women) patients who used the device from 16 to more than 600 days (mean: 889 hours). Improvement in all efficacy variables (p < 0.001) occurred. A dose-response relationship between effect size and hours of usage was observed as cumulative time increased to more than 750 hours. Improvement in patient or physician global occurred in 59.0% of patients who used it less than 750 hours, and for 73.0% of those who used it more than 750 hours. An economic analysis of a sub-group of patients showed that 45.3% reduced nonsteroidal anti-inflammatory drug (NSAID) use by 50.0% or more. CONCLUSIONS: A highly optimized PES device successfully attenuated knee OA symptoms in patients who had failed non-surgical therapy. Less than 250 hours of therapy provided relief, but improvement increased in a dose-response manner after 750 hours of cumulative use.