Researchers studied 66 patients with knee osteoarthritis (OA) and persistent pain higher than 40 mm on a VAS. Patients were age 40 years or older, had OA for longer than 6 months, did not respond to conventional treatment with NSAIDs or acetaminophen, and did not change medications in the prior month. Patients were evaluated at baseline and at 1 month with VAS and WOMAC scores.
Patients were randomly assigned 1:1 to treatment either with a pulsed electromagnetic field-generating device or a placebo device with no electromagnetic properties. Sixty patients completed the study, with three patients from each group lost to follow-up. Rates of compliance were similar between groups, with an average use time of about 11 hours per day reported.
At 1 month, a 25.5% reduction in pain on the VAS was observed in patients who were assigned to the treatment group compared to a 3.6% reduction for patients in the placebo group with a standardized effect size of -0.73 in VAS score.
The WOMAC pain subscale scores were reduced by 23.4%, and an 18% reduction in total WOMAC scores was observed in patients in the treatment group. In contrast, a 2.3% reduction in both WOMAC scores was observed in the placebo group.