A randomized controlled trial found that combining pulsed electromagnetic field therapy with home-based exercise may lead to significant improvements in knee muscle strength and pain reduction in patients with end-stage knee osteoarthritis.
In the 8-week study, published in Frontiers in Medicine, researchers recruited 60 patients with end-stage knee osteoarthritis (OA). The participants were randomly assigned to undergo either home-based exercise alone (control group) or combined with pulsed electromagnetic field (PEMF) therapy (treatment group) in 10-minute sessions twice per week.
The PEMF treatment group showed significant improvements in symptomatic knee extension muscle strength (P = .001), flexion strength (P = .011), and contralateral knee strength at 8 weeks. Specifically, symptomatic knee extension strength increased from 2.40 ± 0.72 N/kg at baseline to 2.85 ± 0.78 N/kg at week 8 in the treatment group, while the control group showed no significant change.
Significant reductions in Visual Analogue Scale pain scores were observed in both groups, with greater improvements in the PEMF group at 4 weeks (P = .010) and 8 weeks (P = .046). The PEMF group's pain scores decreased from 5.93 ± 1.39 at baseline to 4.15 ± 1.68 at week 8 compared with a decrease from 5.63 ± 1.60 to 4.58 ± 1.62 in the control group.
Female patients and those aged over 70 years showed greater improvements in knee muscle strength with PEMF therapy. Male patients were more responsive to PEMF therapy for pain relief.
The study also assessed physical function using gait speed and sit-to-stand tests. Both groups showed improvements in these measures, but there were no statistically significant between-group differences.
The researchers used a commercial PEMF device (Quantum Tx, Singapore) that delivered uniform 1mT amplitude PEMFs at a frequency of 50 Hz. The quadriceps muscles and knees of participants were exposed to the PEMF or sham therapy.
Corresponding study author Dr. Michael Tim-yun Ong, noted that this was the first study to combine PEMF therapy with home-based exercise in end-stage knee OA. The researchers suggested that noninvasive PEMF therapy may be a safe and convenient adjuvant treatment for end-stage knee OA.
However, the study had limitations, including the lack of long-term follow-up and control for other risk factors associated with knee OA. Additionally, the treatment group had a significantly higher body mass index (mean = 26.0) compared with the control group (mean = 24.1) at baseline, which could have influenced the results.
The researchers suggested that the findings may have implications for the management of end-stage knee OA, particularly among patients awaiting total knee replacement. In Hong Kong, where the study was conducted, the waiting time for knee replacement surgery can be 3 to 9 years as a result of high demand and limited resources.
The researchers recommended future studies with longer intervention durations and follow-up periods to further evaluate the potential benefits of PEMF therapy in this patient population.
Conflict of interest disclosures can be found in the study.
