 Introduction This is a continuation of our series on knee osteoarthritis. We discussed Pulsed Electromagnetic Field (PEMF) therapy and its applications in pain management in a blog post dated January 19, 2025. PEMF is known for its effectiveness in reducing pain and improving function in people with various musculoskeletal conditions, including knee osteoarthritis (knee OA). This position is supported by clinical data discussed in a health fact sheet produced by the National Center for Complementary and Integrative Health (NCCIH): “Magnets For Pain: What You Need To Know.” Here, we will update the information provided by the NCCIH on clinical effectiveness and mechanisms of action known to date, with a focus on knee osteoarthritis. Moreover, we will discuss commercial PEMF devices and associated protocols approved by the FDA specifically for the treatment of osteoarthritis, or approved only for the health and wellness consumer market but potentially applicable to osteoarthritis. Clinical trials supporting effectiveness in osteoarthritis including knee osteoarthritis. The cautious recommendation by the NCCIH that “Electromagnetic therapy may be a beneficial complementary therapy for treating osteoarthritis…” was based primarily on the meta-analysis of 12 clinical studies by Wu Z. et al. (2018) and the systematic review of 15 additional studies by Paolucci T. et al. (2020), encompassing a total of 1,370 patients with osteoarthritis affecting primarily the knees, ankles, hands, neck and lower back. Overall, these studies showed that electromagnetic therapy (mostly PEMF) reduced pain, improved physical function and reduced stiffness while being well tolerated. It could be a useful addition to the standard of care currently available to patients, although much remains to be done in optimizing protocols and validating them with larger trials. Since then a number of new randomized controlled clinical studies were reported through 2025. We will summarize some of the more relevant ones below: Hashemi, S. E. et al. (2024) conducted a small study with 70 female patients with primary knee OA. It investigated the effect of low-frequency PEMF (10-100 Hz; the device used was poorly identified but could be an Extremely Low Frequency (<100 Hz) and Low Intensity (< 10 mT) ASA Magnetotherapy device) in addition to a regular schedule of physical therapy. Exposure was 30 minutes at 40% intensity every week day for 3 weeks. Evaluations were conducted at baseline, after 3 weeks of treatment, and at 7 weeks follow-up. The results showed that the PEMF group experienced less pain (measured by the Visual Analog Scale, VAS), lower functional limitation, and reduced stiffness at 7 weeks compared to sham group. Physician Global Assessment (PGA) scores were also superior in the PEMF group versus sham. Similarly to the previous study, Wang, Q. W. et al. (2024) investigated the effect of PEMF in a group of 60 patients with confirmed end-stage osteoarthritis (Kellgren-Lawrence (KL) grade ≥ 3) in one or both knees. PEMF treatment was administered in addition to home-based stretching and strengthening exercises designed by physiotherapists. PEMF treatment consisted of two 10-minute sessions per week for 8 weeks delivered by a Quantum Tx machine generating a uniform 1 mT field intensity at 50 Hz pulse frequency. Both knees were treated in alternate sessions, so each knee was exposed to a total of 8 sessions. Evaluations were conducted at baseline and at 4 and 8 weeks of treatment. The results showed improved knee muscle strength and reduced pain as well as a promising tendency to improve performance-based physical function (as measured by 6-meter walk plus sit-to-stand time) in the PEMF group versus sham. Taken together, both studies supported supplementing exercise and physical therapy routines for knee OA patients with PEMF treatment. The magnetic pulse intensity and frequency required did not exceed 10 mT and 100 Hz, respectively. Session duration was 10 to 30 minutes at a frequency of 2 to 5 sessions per week for no more than 8 weeks. The duration of the beneficial effect beyond 8 weeks and the need for repetition remain to be determined. A recent review by Bhutada, G. et al. (2025) supports this conclusion. Maghroori, R. et al. (2025) further investigated the utility of PEMF as adjunct therapy in a more complex setting where the patient population was already subjected to two forms of therapy: an exercise regimen plus a nonsteroidal anti-inflammatory drug, meloxicam 15 mg daily. PEMF treatment consisted of a 30-minute session with pulse intensity and frequency of 50 Gauss (5 mT) and 75 Hz, respectively. Each patient in a group of 60 diagnosed with grade 2 or 3 knee OA, was treated with 8 sessions of PEMF or sham PEMF over 3 weeks. Evaluations at baseline, end of treatment, and follow-up at 6 weeks and 3 months after treatment showed that the addition of PEMF therapy substantially enhanced pain relief and physical function with no reported side effects. The findings support the use of PEMF as adjunct therapy for knee OA patients who are concomitantly treated with exercise and an NSAID agent. In a similar complex setting comprising a population of 120 patients suffering from knee OA, Kellgren-Lawrence (KL) grade ≥ 2, Wang, R. et al. (2026) investigated the effect of adding PEMF to two established therapies in China: exercise and external Chinese herbal therapy (Sanqi Shengyu External Application Cream). The PEMF protocol was distinct in using a much higher magnetic pulse intensity of 800 mT at a pulse frequency of 50 Hz for 30 minutes. Patients in the PEMF group were treated for a total of 20 sessions over 4 weeks. Evaluations were conducted at baseline, end of treatment, and at 4-week follow-up. The results of 4 treatment arms (exercise only as control, exercise + PEMF, exercise + external Chinese herbal therapy, and combination of exercise + PEMF + external Chinese herbal therapy) showed that the combined therapy group demonstrated superior outcomes, especially at the 4-week follow-up. The beneficial effect of external Chinese herbal therapy alone was durable, while that of PEMF diminished over time after intervention. The exercise-only control group also showed significant improvements but less pronounced than the active intervention groups. Direct comparison of the results by Maghroori, R. et al. (2025) and Wang, R. et al. (2026) would not be possible because of the differences in PEMF protocols and control design. Nevertheless, both sets of results support the application of PEMF as an adjunct to multimodal therapies that include exercise and anti-inflammatory agents. Studies to optimize PEMF dosing (i.e. carrier frequency, pulse intensity and frequency, treatment duration required to achieve specific goals: pain & stiffness reduction, function improvement, cartilage degradation) are crucial for advancing PEMF as a treatment option. To that effect, Yang, X. et al. (2025) reported that at fixed magnetic field intensity (3.8 mT), higher PEMF pulse frequency (75>50>8 Hz) resulted in better recovery in a rat model of knee osteoarthritis. Ye, L. I. (2025) reported some preliminary efforts in studies of varying field intensity in a mouse model, but detailed results have yet to be published. Two additional clinical trial results need to be discussed as a separate category considering the characteristics of the PEMF protocols and the commercial nature of the devices employed. In contrast to PEMF protocols using magnetic pulse intensity in the mT range and pulse frequency < 100 Hz, the following two trials employed PEMF with carrier frequency in the radiofrequency (27.12 MHz) range, i.e. magnetic pulse intensity probably in the μT range or less, and pulse frequency ranging from 2 to 1,000 Hz. At such low intensity and wide range of pulse frequencies these electromagnetic pulses (often referred to as Pulsed Radiofrequency/Shortwave Therapy, or PRF/PSWT) can still penetrate soft tissue to disrupt chronic pain signaling and induce analgesia, among other effects. Whether the two distinct sets of protocols operate similarly at the cellular or molecular level remains to be determined for particular biological applications Hackel, J. G. et al. (2025) reported a prospective study with 120 patients suffering from diverse soft tissue or joint pain (ankle, back, knee, wrist, elbow, shoulder, foot, hip, or neck) although knee pain predominated (43%) . Patients were randomized, but the study was not blinded and included two arms: PEMF and Standard of Care (SOC). Patients in the PEMF arm self-administered the treatment with a commercial device (Orthocor Active System) operating at 27.12 MHz carrier radiofrequency, pulse frequency of 2 Hz, pulse duration of 2 ms, and classified by the FDA as a short-wave diathermy device. The treatment consisted of daily 2-hour sessions for 14 days per manufacturer instructions. After 14 days, patients in the SOC arm were allowed to cross over. The two key endpoints for the study were efficacy measured by changes in pain score from baseline, and safety measured by the number of adverse events. The overall results showed that use of the Orthocor device was safe and led to significant reductions in pain and medication use compared to the standard of care for joint and soft tissue pain. Durtschi, M. S. et al., 2025, reported on a single-center, double-blind, randomized, controlled trial with 61 patients suffering from thumb carpometacarpal (CMC) osteoarthritis to test the effectiveness of another commercial PEMF device, the ActiPatch made by BioElectronics, classified by the FDA as Non-Thermal Shortwave Device. The device operates at 27.12-MHz carrier radiofrequency, pulse frequency of 1,000 Hz, pulse duration of 0.1 ms. The study consisted of two arms: patients in a treatment group wore the device overnight for 4 weeks whereas patients in the control group similarly wore a sham device not emitting the radiowave. Two endpoints were considered: pain reduction and function improvement. Evaluations were conducted at baseline, at 4 weeks end of treatment, and at 6 weeks follow-up. The results showed that both PEMF and sham groups achieved pain reduction and function improvement at the end of treatment (4 weeks), but no statistical difference could be discerned between the two groups. At 6 weeks follow-up, however, the pain reduction was sustained in the PEMF group only. The placebo effect was substantial but did not extend beyond the treatment period. Effectiveness ranking of PEMF versus Extracorporeal shock wave therapy (ESWT), Low-level laser (LLLT) and Microwave (MW) therapy. In a study of 120 patients aged 40-70 and diagnosed with knee OA, Kellgren-Lawrence (KL) grade 2-3, Pasin, T., & Dogruoz Karatekin, B. (2025) compared the efficacy of PEMF against two other non-pharmacological treatment modalities: extracorporeal shock wave therapy (ESWT) and low-level laser therapy (LLLT). The patients were divided into four groups of 30 participants each —three groups received their respective treatment interventions while one served as untreated control. The PEMF intervention consisted of 20-minute sessions twice weekly over 4 weeks, using a magnetic pulse intensity of 10 mT and and frequency of 30Hz. Overall, beneficial effects (pain reduction, decreased stiffness, and improved physical functions) were observed for all 3 interventions compared to the control group. However, PEMF was found to be less effective than ESWT and LLLT, which demonstrated roughly equal effectiveness. In summary: ESWT ≈ LLLT > PEMF. In another comparative study, Comino-Suárez, N. et al. (2025) investigated the effects of PEMF and microwave therapy (MW) combined with a standardized exercise regimen (EX). This three-arm randomized, blinded clinical trial included 60 patients with unilateral or bilateral knee osteoarthritis, Kellgren & Lawrence grade 2 or 3, divided into groups receiving EX+PEMF, E+sham PEMF, and EX+MW. All three interventions were delivered over 12 sessions (3 sessions per week for 4 weeks). The PEMF treatment consisted of 20-minute exposures at a pulse intensity of 10 mT and frequency of 50 Hz. Results showed that although all three groups exhibited improvement in most VAS and WOMAC scores after treatment and at 1- and 3-month follow-ups, the EX+PEMF group outperformed the other two, particularly during the 1- and 3-month follow-up periods. These finding complement and extend the report by Cao, S. et al. (2024) who compared the effectiveness of acupuncture for knee OA against 6 other non-pharmacological treatment modalities: needle-knife therapy (acupotomy), exercise, transcutaneous electrical nerve stimulation (TENS), ultrasound, shock wave therapy, and laser therapy (see our previous blog, 11/15/2025). Shock wave therapy was superior to all others based on VAS and WOMAC scale assessment following treatment. Mechanistic aspects Studies on the mechanism of pain modulation and articular cartilage stabilization by PEMF (Pilla, A. et al., 2011, Iwasaka, K. & Reddi, A., 2018, Bragin, D. E. et al., 2015) established the following basic understanding:
Since 2020, additional advances have been achieved in delineating the molecular features of osteoarthritic tissues and how they are affected by PEMF treatment . These advances are summarized below: Using a cellular model of human chondrocytes (C28/I2) stimulated with interleukin (IL)-1β and a mouse model of osteoarthritis, Zhou, S. et al. (2025) demonstrated that upregulation of Sirt1 (a transcription factor deacetylase) by PEMF blocks the activation of the pivotal pro-iinflammatory NF-κB signaling pathway, which is often overactive in osteoarthritic joints. This finding is important as it adds to our understanding of the molecular events induced by PEMF that lead to decreased inflammation at the joints and slowing of disease progression. Inhibiting the NF-κB signaling pathway induced by interleukin (IL)-1β is part of an overall strategy for developing therapeutic agents for the treatment of osteoarthritis. Working with primary human chondrocytes, Bao, C. et al. (2025) showed that the glycolysis rate increases in chondrocytes from arthritic cartilage, accompanied by upregulation of hexokinase II (HEK2). Overexpression of HEK2 promotes an inflammatory response and catabolism while inhibiting anabolic activities. Concommitant with the increased expression of HK2 was a decrease in expression of HMGA2, a DNA-binding protein capable of transcriptional regulation. The authors also showed that PEMF inhibits the expression of HEK2 and increases HMGA2, leading to a reversal of the iinflammatory and catabolic state in the chondrocytes. Lonidamine, an inhibitor of HK2, performed similarly. In a mouse model of osteoarthritis, lonidamine in combination with PEMF more effectively reversed cartilage degeneration. Finally, HK2 was proposed as a potential target for developing therapeutic agents for the treatment of osteoarthritis. Over past decades, exposure to PEMF has been shown to have beneficial effects not only in bone and cartilage but also in tendons and muscles. Tendinopathy and muscle atrophy tend to stress joint structures and contribute to the development of osteoarthritis. As a result, mechanistic studies in those tissues were also of interest. The information developed from either approach tends to enhance and complement each other. Using proteomic analysis of rat muscles subjected to experimentally induced tendinopathy, Torretta, E. et al. (2024) reported that glycolysis in these tissues is enhanced. When exposed to PEMF, changes in the pattern of cellular proteins support a switch towards oxidative phosphorylation, as evidenced by the increase in LDHB, which converts lactate to pyruvate, boosting NAD+ signaling, ATP production, and beta-oxidation of fatty acids. PEMF also increases the level of antioxidant proteins which control the damage caused by reactive oxygen species (ROS). Two key transcription co-activators, PGC1alpha and YAP, were upregulated by PMEF. The former is clearly linked to the increase in oxidative metabolism, anti-iinflammatory state, and antioxidant effects. The latter supports tissue repair and regeneration, and cell proliferation (Maiullari, S. et al., 2023). PEMF devices available to medical professionals and consumers In a previous blog post (01/19/2025) we discussed various venues for accessing electromagnetic therapy for pain management. Now we’ll dwell into the devices available on the market for both medical professionals (doctors, therapists) and the general consumers responding to medical guidance, or just interested in self-help for osteoarthritis. The market can be broadly categorized into devices cleared by regulatory bodies for specific medical uses and those marketed for general health, pain, and wellness (more common in the consumer market). I. Medical Device Market (Often FDA-Cleared/Approved) These devices are typically intended for use under the guidance of a healthcare professional, with specific indications for use that may include post-operative pain, edema, and osteoarthritis.
Note: While the primary FDA indications for many Orthofix and DJO devices are bone healing (non-union fractures or spinal fusion), PEMF technology, in general, is cleared for conditions like post-operative osteoarthritis and pain/edema. The ActiPatch is specifically cleared for knee osteoarthritis for non-prescription use. Except for the two Orthofix devices (Physio-Stim and Spinal-Stim) all others in the list are in fact Pulsed Radiofrequency/ Shortwave Therapy types operating at 27.12 MHz carrier frequency. II. Health & Wellness Consumer Market These are typically sold directly to consumers for home use, often marketed for general wellness, pain relief, improved circulation, and reduced inflammation, which are beneficial for osteoarthritis symptoms. They may not have specific FDA clearance for treating osteoarthritis but are marketed under general wellness claims.
Concluding remarks The available evidence supports the effectiveness of PEMF as an adjunctive treatment for different forms of osteoarthritis, particularly for relief from pain and inflammation. Proof of a beneficial effect on cartilage degradation remains at the experimental level in animal models. It has yet to be validated quantitatively in a randomized clinical setting with adequate control. Conservatively, patients could opt for any of the FDA-approved device and protocol under guidance from medical professionals, and as adjunct to exercises and physical therapy in addition to judicious application of pharmacological interventions. Devices approved for marketing for home use and general wellness are likely safe enough for those willing to explore therapeutic approaches still under development. References
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