Study Examines Use of PEMF to Treat Knee Conditions

By: Jennie McKee

Pulsed electromagnetic field therapy found effective, well-tolerated

Jennie McKee

Findings of a randomized, controlled trial performed in Italy suggest that biophysical therapy with pulsed electromagnetic fields (PEMF) can be used to successfully treat patients with symptomatic bone marrow edema (BME) or localized cartilage injury.

PEMF—which permeates joints and articular cartilage—is “an easy-to-use treatment that avoids any possible side effects typical in drug treatments,” according to the authors of Scientific Poster 113, on display in Academy Hall G. The authors add that PEMF therapy is “well-tolerated by patients.”

According to the investigators, PEMF has been found effective in treating patients in the first stages of spontaneous osteonecrosis of the knee. This study, however, analyzed whether PEMF is effective in patients with BME of the knee.

Conducting the study
This prospective study included 32 patients (21 males and 11 females); patients had a mean age of 52.8 years. All patients had symptomatic BME of the knee, as identified via magnetic resonance imaging (MRI). Patients were randomly divided into two groups of 16 patients: a control group (that received no treatment at all and was allowed to do weight bearing as tolerated) and a group that received local PEMF with a specific combination of physical parameters (peak intensity 1.5 mT, frequency 75 Hz, 4 hours daily for 90 days).

The investigators performed clinical evaluations of the patients prior to treatment and at 3 months, 6 months, and 1 year. They assessed patients using the visual analog scale (VAS), Knee Society Score (KSS), Tegner Activity Score, and EuroQol-5D (EQ 5D), the last of which is a validated measure of general health status. For comparison purposes, MRI was performed before treatment and at 6 months. The area of bone marrow lesions was measured and graded using the Whole Organ Magnetic Resonance Imaging (WORM) score.

Assessing Results
At 6 months, patients who received PEMF therapy had significantly reduced pain (from 67.2 ± 21.5 to 26.6 ± 18.4, P < 0.0001). Pain scores remained almost unchanged at 1 year. The treatment group’s initial mean KSS was 63 (range: 53 to 75), while the control group’s mean KSS was 58 (range: 52 to 72). At 6 months, the treatment group’s mean KSS had increased to 88 (P < 0.001), while the control group’s mean KSS had increased to 70 (P < 0.005). At 1-year follow-up, however, mean KSS were slightly reduced for both groups.

The researchers also noted that Tegner median levels increased from baseline to 6-month follow-up and remained stable, while EQ-5D scores improved significantly throughout the study period of 1 year.

The researchers found a reduction in total WORM mean scores, as well as a reduction in mean femoral bone marrow lesion area. All told, bone marrow lesion area was reduced in 85 percent of the treatment group.

“The study suggests that treatment with PEMF therapy represents a valid biophysical therapeutic approach for BME or localized cartilage injury,” concluded the researchers.

The authors of Scientific Poster 113, “Spontaneous Bone Marrow Edema of the Knee: The Role of Biophysical Treatment with Pulsed Electromagnetic Fields” are Dario Perugia, MD; Marco Guidi, MD; and Andrea Ferretti, MD.

Details of the authors’ disclosure as submitted to the Orthopaedic Disclosure Program can be found in the Final Program; the most current disclosure information may be accessed electronically at