Knee osteoarthritis is a very painful condition that often limits activities of daily living (ADL). Several studies have demonstrated that therapeutic exercises, including exercise with Thera-Band elastic resistance products, can reduce pain and increase function in knee osteoarthritis patients. Knee osteoarthritis is also associated with inhibition of the quadriceps, which leads to poor knee extensor strength. This is referred to as “arthrogenic muscle inhibition.” In addition, quadriceps weakness is a primary risk factor for development of knee osteoarthritis.
Knee strengthening exercises with Thera-Band elastic resistance products have shown improvements in knee osteoarthritis pain and function (Topp et al. 2002). Unfortunately, knee arthritis patients may not be able to experience the benefits of therapeutic exercise since knee pain is often a barrier to exercise. Researchers wanted to find out if adding transcutaneous electrical nerve stimulation (TENS) to a knee osteoarthritis exercise program was more effective than an exercise program without TENS. 36 patients were randomly assigned to exercise with TENS or an exercise group with a TENS placebo. The 4 week exercise program included stretching, strengthening, step-ups, balance training, and a wall-squat exercise with an exercise ball.
After the 4-week program, the patients using TENS had significantly higher quadriceps muscle activation than the placebo group. Both groups improved their scores on a self-reported functional WOMAC scale, but there was no significant difference between the TENS and placebo groups. While there was no statistically significant difference between groups, the effects were greater in the TENS combined with exercise group.
In conclusion, adding TENS to a therapeutic exercise program for knee osteoarthritis can be more effective at increasing quadriceps muscle activation by reducing pain during exercise. In addition, knee osteoarthritis patients can improve self-reported function with exercises including strength and balance training, either with or without TENS.
REFERENCE: Pietrosimone BG, et al. Effects of transcutaneous electrical nerve stimulation and therapeutic exercise on quadriceps activation in people with tibiofemoral osteoarthritis. J Orthop Sports Phys Ther. 2011 Jan;41(1):4-12. Epub 2010 Dec 31.