MADISON, Wisconsin— Pulsed electrostimulation (PES) may be a safe and effective way to reduce pain and improve function in people with knee osteoarthritis (OA) and may even stave off the need for joint arthroplasty, according to a new study in the June issue of the journal Osteoarthritis and Cartilage.¹ The device used in the study was created by BioniCare Medical Technologies, Inc, in Sparks, Maryland. Bionicare also funded the study.

"Knee OA causes severe disability in millions of people [and] those with moderate or severe disease who fail analgesics and/or NSAIDs (nonsteroidal anti-inflammatory drugs) have limited therapeutic options. Some choose  TKA (total knee arthroplasty) or other types of surgery, but many are unwilling or are too young, too old, or too enfeebled by co-morbid disease to consider surgery," conclude the researchers led by Douglas Garland, MD, the director of the division of neurotrauma at Rancho Los Amigos Medical Center in Downey, California. "PES offers a safe, noninvasive option for such patients and may reduce the need for TKA  as well."

The  3-month, randomized, double-blind, placebo-controlled study included 58 outpatients with moderate-to-severe knee OA who were randomized to wear an active or placebo device at home for 6 to 14 h/day. To use the device, patients applied a conducting gel to each electrode. Then they positioned the appliance with the negative electrode on the skin over the patella and placed the positive-return electrode over the anterior distal thigh. Patients turned on the device and increased the signal amplitude to between 0 and 12 V via a rotating dial until a tingling sensation could be felt on the knee or thigh. They then reduced the amplitude until the sensation disappeared.

Exactly how pulsed electrostimulation improves knee OA pain and function is not fully understood, but the study authors speculate that "an in vitro signaling of articular cartilage explants has shown increased messenger RNA transcription of genes that promote synthesis of chondrocyte, Type II collagen and aggrecan, and suppression of matrix metalloproteinase and interleukin-1."

Electrostimulation outshines placebo

In the study, patients who wore the pulsed electrostimulation device showed a 50.6% greater improvement than their counterparts who wore the placebo device in the patient global evaluation (P  = .03) and also  a 31.2% greater improvement in pain (P  = .04). Compared with participants who wore the placebo device, patients who wore the active  device had a 25.1% greater improvement in the Western Ontario and McMaster Universities (WOMAC) stiffness score (P  = .03), a 29.5% greater improvement in WOMAC function (P  = .01), a 19.9% greater improvement in WOMAC pain (P  = .11), and 27% greater improvement in the total WOMAC (P  = .01).

The percentage of patients who improved by more than 50% was 38.5% in the active group versus 5.3% in the placebo group in patient global (P  = .01), 43.6% versus 15.8% in patient pain (P  =.04), 38.5% versus 10.5% in WOMAC pain (P  = .03), 28.2% versus 5.3% in WOMAC stiffness (P  = .08), 23.1% versus 5.3 % in WOMAC function (P  = .14), and 23.1% versus 5.3% in total WOMAC (P  = .14).

A total of  21% of placebo and 18% of actively treated patients developed a rash at the electrode sites, but  no other adverse device effects were reported.

"This is a wonderful device that works quickly and is very efficient at improving function and decreasing pain and the need for medications in knee OA patients," said Atlanta-based rheumatologist Theresa Lawrence-Ford, MD, who uses the device.

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Reference

1. Garland D, Holt P, Harrington, JT, et al. A 3-month, randomized, double-blind, placebo-controlled study to evaluate the safety and efficacy of highly optimized, capacitively coupled, pulsed electrical stimulator in patients with osteoarthritis of the knee. Osteoarthritis and Cartilage. 2007;15:630-637.