Early Neuromuscular Electrical Stimulation For Quadriceps Muscle Activation Deficits Following Total Knee Replacement

Osteoarthritis (OA) is a chronic degenerative joint disease that disables about 10% of people over the age of 60 and compromises the quality of life of more than 20 million Americans. To alleviate pain and disability associated with knee OA, over 400,000 total knee arthroplasty (TKA) are performed each year in the United States, and future projections indicate that by the year 2030, more than 750,000 TKAs will be performed per year. While TKA reliably reduces pain and improves function, the recovery of force and function to normal levels is rare, which predisposes patients to future disability with increasing age. A month after TKA, impairments in quadriceps force are predominantly due to reflex inhibition, but are also influenced, to a lesser degree, by muscle atrophy. Neuromuscular electrical stimulation (NMES) may offer a promising alternative approach to override quadriceps reflex inhibition and prevent muscle atrophy to restore normal quadriceps muscle function more effectively than voluntary exercise alone, especially when applied within the first days after surgery.

The overall goal of this study is to evaluate the efficacy of NMES initiated 48hrs after TKA as an adjunct to standard rehabilitation. NMES is expected to more effectively restore normal quadriceps muscle function to produce greater quadriceps force by decreasing reflex inhibition. Patients will be randomized into one of two rehabilitation groups: 1) the standard rehabilitation group or 2) standard rehabilitation + NMES.

Inclusion criteria

• 50-85 years of age
• Scheduled for a primary unilateral TKA
• Cognitive status that allows patients to consistently comprehend and repeat back directions regarding the details of the study

Exclusion criteria

• History of uncontrolled hypertension or uncontrolled diabetes
• Body mass index greater than 35 kg/m^2
• Neurological, vascular or cardiac problems that significantly limit function
• Moderate or severe osteoarthritis or other orthopedic conditions in the non-operated lower extremity that limit function