Prospective Case Series of NMES for Quadriceps Weakness and Decrease Function in Patients with Osteoarthritis of the Knee.

Osteoarthritis of the knee can lead to substantial disability. The purpose of this study was to evaluate the outcomes of a neuromuscular electrical stimulation (NMES) device in a small case series of treatment of quadriceps muscle weakness and decreased function in patients with knee osteoarthritis. We evaluated isokinetic quadriceps muscle strength, objective functional improvement, subjective functional improvement, quality of life, and pain relief. Patients were then matched with a previously studied cohort with similar osteoarthritic characteristics. Testing demonstrated improvement in isokinetic quadriceps and hamstring muscle strength, as well as several functional and patient-reported metrics. Conversely, patients reported a decrease in Knee Society Score (KSS) functional score, short-form 36 health survey (SF-36), lower extremity functional scale (LEFS), and visual analog scale (VAS) for pain; however, no changes were observed in relation to the mean reported VAS pain score and SF-36 physical component. Control cohort analysis of the patient reported outcomes showed that patients improved from their first visit to 3 months follow-up in functional KSS, SF-36 physical component, and LEFS. However, VAS pain score and objective KSS were unchanged at follow-up. Similarly, a decrease was observed in the scores of the SF-36 mental component. In conclusion, the use of NMES for quadriceps muscle weakness has been shown to improve muscle strength. Additionally, NMES was shown to potentially improve functionality but demonstrated minimal effects on quality of life and patient-reported outcomes compared with the initial visit. However, larger, longer-term, prospective, randomized studies are needed to better evaluate these outcomes.