Comparison of the Effect of Sensory-Level and Conventional Motor-Level Neuromuscular Electrical Stimulations on Quadriceps Strength After Total Knee Arthroplasty: A Prospective Randomized Single-Blind Trial.

OBJECTIVE:To compare sensory-level neuromuscular electrical stimulation (NMES) and conventional motor-level NMES in patients after total knee arthroplasty. DESIGN:Prospective randomized single-blind trial. SETTING:Hospital total arthroplasty center: inpatients. PARTICIPANTS:Patients with osteoarthritis (N=66; mean age, 73.5±6.3y; 85% women) were randomized to receive either sensory-level NMES applied to the quadriceps (the sensory-level NMES group), motor-level NMES (the motor-level NMES group), or no stimulation (the control group) in addition to a standard rehabilitation program. INTERVENTIONS:Each type of NMES was applied in 45-minute sessions, 5d/wk, for 2 weeks. MAIN OUTCOME MEASURES:Data for the quadriceps maximum voluntary isometric contraction, the leg skeletal muscle mass determined using multiple-frequency bioelectrical impedance analysis, the timed Up and Go test, the 2-minute walk test, the visual analog scale, and the range of motion of the knee were measured preoperatively and at 2 and 4 weeks after total knee arthroplasty. RESULTS:The motor-level NMES (P=.001) and sensory-level NMES (P=.028) groups achieved better maximum voluntary isometric contraction results than did the control group. The motor-level NMES (P=.003) and sensory-level NMES (P=.046) groups achieved better 2-minute walk test results than did the control group. Some patients in the motor-level NMES group dropped out of the experiment because of discomfort. CONCLUSIONS:Motor-level NMES significantly improved muscle strength and functional performance more than did the standard program alone. Motor-level NMES was uncomfortable for some patients. Sensory-level NMES was comfortable and improved muscle strength and functional performance more than did the standard program alone.