Pulsed Electromagnetic Field Therapy in People with Knee Osteoarthritis: A Systematic Review and Meta-Analysis.

Background and

Objectives

Knee osteoarthritis (KOA) is a major cause of global disability. The efficacy of a non-invasive treatment, pulsed electromagnetic field (PEMF) therapy, remains debated. This systematic review and meta-analysis evaluate PEMF's effectiveness on KOA, exploring the influence of device parameters. Materials and

Methods

We systematically searched PubMed, Embase, and the Cochrane Library for randomized controlled trials (RCTs) from 2015 to 2025. Nine RCTs with a total of 457 patients were included. Primary outcomes were pain (Visual Analog Scale-VAS) and function (Western Ontario and McMaster Universities Osteoarthritis Index-WOMAC). Data were pooled using a random-effects model with subgroup analyses based on PEMF amplitude and frequency.

Results

No significant improvement in VAS pain or total WOMAC scores was found at one month. However, time-dependent effects were observed. WOMAC-pain improved significantly at 18-21 days (MD = -1.63, 95% CI: -2.43 to -0.82, I2 = 28%) but not at one month. Conversely, WOMAC-stiffness (MD = -1.11, 95% CI: -1.386 to -0.85, I2 = 0%) and daily activity (MD = -3.39, 95% CI: -4.81 to -1.97, I2 = 0%) improved significantly only at the one-month. Objective functional measures did not improve, and the overall risk of bias across studies was high. The efficacy of PEMF is also influenced by the amplitude and frequency.

Conclusions

PEMF efficacy for KOA is nuanced, with benefits dependent on timing and device parameters. High frequency gives fast pain relief; high amplitude builds function. Though statistically significant, these improvements may not reach thresholds for clinical meaningfulness. Significant heterogeneity in treatment protocols is a major barrier to clear conclusions. Standardized, large-scale RCTs are needed to determine optimal parameters and confirm PEMF's clinical role.