The study evaluating electromagnetic field treatments for knee OA patients depicted that at short term follow-up, pulsed magnetic/electromagnetic field (PMF, PEMF) therapies are safe and effective treatments for the management of knee OA-related pain and disability. However, it is not superior to other conservative therapies such as physiotherapy, TENS (Transcutaneous electrical nerve stimulation), ultrasound, or hyperthermia.  

This systematic review and meta-analysis aimed to evaluate the effect of electromagnetic field treatment on relieving the symptoms of knee OA. The secondary objective was  to evaluate the efficacy of these therapies when compared to other conservative approaches.

The study incorporated randomized controlled trials reporting pulsed electromagnetic field-based therapies for the management of knee OA. The primary outcomes were self-reported pain and activity scores estimated by VAS (Visual Analogue Scale) and/or WOMAC (Western Ontario McMaster Universities Osteoarthritis Index) in the short term after treatment.

The analysis included about 13 studies comprising 914 unique patients. The overall reduction in pain score was witnessed after treatment (standardized mean difference −0.4059). On the other hand, improvement in the activity score was not substantial (standardized mean difference −0.4452).

The two major elements influencing the outcomes were the time of follow-up and the type of control (i.e., placebo or alternative therapies). Indeed, the restriction of the analysis to placebo-controlled trials illustrated elevated standardized mean differences between treatment and control groups, with lower P-value for pain.

For the activity score, the statistical significance also became evident. While pooling only studies comparing pulsed electromagnetic or magnetic fields to alternative treatments, no differences were seen. Furthermore, longer follow-up correlated with lower differences between treated and control patients.

In the short term, pulsed electromagnetic field therapy effectively relieves knee OA symptoms.