Highlights:
- Significant pain relief in just one month: Daily use of the wearable PEMF knee device for 12 hours over 4 weeks led to a clinically meaningful reduction in pain versus placebo on both VAS and WOMAC, with a medium effect size for pain improvement.
- Better function and pain tolerance: In addition to less pain, patients reported improved physical health scores and higher pressure pain thresholds, suggesting PEMF may help the nervous system become less reactive to pain.
- Less reliance on pain medication: By the end of the study, about one in four participants (26%) in the PEMF group were able to stop using NSAIDs or other analgesics, hinting at a potential medication-sparing effect.
- Non-invasive and well tolerated: The low-intensity, wearable PEMF device was used for extended daily sessions without any reported adverse events, supporting its role as a safe, drug-free option for chronic knee osteoarthritis pain management.
Knee osteoarthritis (OA) is a common cause of chronic pain and stiffness, often limiting walking, exercise, and daily activities. This clinical trial asked a simple question: can a small wearable pulsed electromagnetic field (PEMF) device help reduce pain and improve function in people with knee OA?
Study at a Glance
Researchers enrolled 66 adults with chronic knee OA pain, confirmed on X-ray and with pain scores above 40 mm on a 0–100 mm pain scale.
Participants were randomly assigned to:
- Active PEMF device, worn on the painful knee 12 hours per day for 1 month, or
- Sham (placebo) device, identical in appearance but inactive.
Pain and function were measured using standard tools:
- VAS and WOMAC – how much the knee hurts and how much it interferes with daily activities
- SF-36 – overall physical health and quality of life
- Pressure pain threshold – how sensitive the knee is when pressure is applied
Use of NSAIDs and other pain medications was also tracked.
What Did the Study Find?
After 1 month of treatment:
- Less pain than placebo: The PEMF group showed a significant reduction in pain compared with the sham group on both VAS and WOMAC, with a medium effect size (d ≈ –0.73).
- Better function and tolerance to pain: Patients using PEMF reported improvements in physical health scores and could tolerate more pressure on the knee before feeling pain.
- Reduced need for pain medication: About 26% of patients in the PEMF group stopped using NSAIDs or other analgesics during the study period.
- No reported side effects: The wearable device was used for long daily sessions without any adverse events noted.
Figure 1. Improvement in Pain, Function, and Pain Tolerance After 1 Month of PEMF vs Placebo. Bars show change from baseline to 1 month in VAS pain, WOMAC pain, WOMAC function, and quadriceps pressure pain threshold (QDR PPT). Positive values indicate improvement. Compared with placebo, the PEMF group showed larger reductions in pain and disability and greater gains in pain tolerance. Stars (*) indicate statistically significant between-group differences at 1 month (p < 0.05).
What Do the Authors Conclude?
The authors suggest that PEMF therapy is a promising, non-drug option for managing chronic knee OA pain. The gains in function and pain threshold point toward a possible neuromodulatory effect — helping the nervous system react less strongly to pain signals.
They recommend larger and longer studies, and direct comparisons with standard drug treatments, to better define how PEMF should fit into knee OA care.
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