Osteoarthritis (OA) is a debilitating condition affecting millions worldwide, and its management remains a challenge. But here's where it gets controversial: while exercise and neuromuscular electrical stimulation (NMES) are widely touted as effective treatments, their true impact on OA symptoms is still up for debate. This article delves into the effects of different NMES modalities on knee OA, a condition that affects a staggering 240 million people globally, with a focus on pain relief, functional improvement, and overall quality of life.
Osteoarthritis is a chronic, degenerative disease characterized by the breakdown of cartilage and bone remodeling in synovial joints. Over time, this leads to structural changes, including cartilage erosion, synovitis, and subchondral bone sclerosis, resulting in pain, stiffness, and functional limitations. The knee is one of the most commonly affected joints, with prevalence rates ranging from 7% to 35.1% in adults over 45. Risk factors such as age, obesity, genetic predisposition, and metabolic alterations play a significant role in OA development.
Exercise has long been a go-to intervention for OA due to its cost-effectiveness, with both traditional and online programs showing improvements in pain, function, and quality of life. NMES, particularly when combined with exercise, has emerged as a promising complementary treatment. Studies have demonstrated its effectiveness in reducing pain and increasing muscle strength, especially in the quadriceps femoris, a key stabilizer of the knee. However, the optimal NMES parameters and their long-term effects remain unclear.
Different NMES waveforms, such as interferential current (IFC), Aussie current, and transcutaneous electrical nerve stimulation (TENS), have been used to manage chronic pain in OA. TENS, in particular, has gained popularity due to its low cost and ease of use. However, the debate surrounding the effectiveness of these modalities persists, with some studies showing similar pain relief effects between IFC and TENS, while others highlight the need for rigorous, long-term randomized controlled trials (RCTs) to establish consistent clinical protocols.
And this is the part most people miss: the combination of NMES with other therapeutic approaches, such as exercise, may be the key to unlocking its full potential. A systematic review revealed that combining NMES with exercise yielded significant improvements in pain intensity and disability, suggesting a synergistic effect. However, the intensity, duration, and frequency of NMES application, as well as the lack of standardized protocols, remain significant challenges.
Our study aimed to compare the effects of TENS, IFC, and Aussie currents on pain, disability, and pressure pain threshold in older adults with knee OA. We hypothesized that all NMES modalities would outperform a placebo intervention in improving symptoms and function. However, our findings suggest that while IFC and Aussie currents showed moderate improvements in the WOMAC index, similar results were observed in the placebo group, indicating that NMES alone may not be superior to a placebo intervention.
The lack of significant differences between NMES and placebo groups could be attributed to various factors, including the intensity and duration of stimulation, the absence of movement-evoked pain measurements, and the potential for regression to the mean. Furthermore, the neuromatrix theory of pain highlights the complex interplay between sensory, cognitive, emotional, and contextual factors, which may influence treatment outcomes.
So, what's the takeaway? While NMES shows promise as a complementary treatment for knee OA, its effectiveness remains uncertain. The need for optimized parameters, longer intervention durations, and combined therapies is evident. As we continue to explore the potential of NMES, one question lingers: can we truly unlock its therapeutic potential, or will it remain a controversial and elusive treatment option? We invite readers to share their thoughts and experiences, as the debate surrounding NMES and its role in OA management is far from over.
