This study aimed to evaluate the effectiveness of pulsed electromagnetic field (PEMF) therapy in reducing pain and improving function in patients with knee osteoarthritis (OA), through a rigorously controlled clinical trial.
Intervention Used in the Study
This double-blind, placebo-controlled, randomized clinical trial included 66 patients diagnosed with knee OA, confirmed by radiographic evidence and pain scores over 40 mm on the Visual Analog Scale (VAS). Sixty participants completed the study. The intervention involved daily use of a wearable PEMF device (ActiPatch) for 12 hours a day over a 1-month period.
The device delivered non-ionizing electromagnetic radiation with a carrier frequency of 27.12 MHz, pulsed at 1000 Hz with 100 µs bursts, and had a peak output of approximately 0.0098 W across a surface area of ~103 cm². It was applied directly to the knee, using low-voltage (3 V) digital/analog electronics to control pulse delivery. Primary outcomes were pain reduction (VAS and WOMAC scores), and secondary outcomes included physical health (SF-36), pressure pain threshold (PPT), and changes in NSAID/analgesic use.
Results Presented by the Study
After 1 month, PEMF therapy significantly reduced pain compared to placebo, as measured by both VAS and WOMAC scores. The treatment produced a medium effect size (-0.73 for VAS pain). Improvements in physical health and pain tolerance were also noted, with 26% of patients discontinuing NSAID or analgesic use. Importantly, no adverse events were reported throughout the study.
Authors’ Interpretation
The authors concluded that PEMF therapy is an effective, non-pharmacologic option for managing chronic knee OA pain. The improvements in physical function and pain threshold suggest a possible neuromodulatory mechanism. They advocate for larger, long-term studies and direct comparisons with standard drug therapies to better define PEMF’s role in OA management.
Reference: Bagnato GL, Miceli G, Marino N, Sciortino D, Bagnato GF. Pulsed electromagnetic fields in knee osteoarthritis: a double blind, placebo-controlled, randomized clinical trial. Rheumatology (Oxford). 2016; 55(4):755-762. doi:10.1093/rheumatology/kev426