Neuromuscular Electrical Stimulation after Anterior Cruciate Ligament Reconstruction

This randomized controlled trial examined the effects of adding neuromuscular electrical stimulation to rehabilitation exercise on quadriceps muscle strength (primary outcome) and secondary exploratory outcomes after anterior cruciate ligament reconstruction. Twenty-four male participants were randomly allocated to rehabilitation exercise alone or combined with neuromuscular electrical stimulation. Both groups performed range of motion exercises during weeks 1 to 3, followed by progressive quadriceps strengthening three times weekly for 9 weeks. Both groups improved in isokinetic muscle function, with larger effect sizes in the resistance exercise+neuromuscular electrical stimulation group (d=0.883-1.488) than in the resistance exercise group. Patient-reported outcomes improved in both groups for the Lysholm score (d=1.527 vs. 0.653), whereas changes in the International Knee Documentation Committee score were greater in resistance exercise+neuromuscular electrical stimulation (d=1.006 vs. 0.034). Balance improved with larger effects in resistance exercise+neuromuscular electrical stimulation under stable (d=0.710 vs. 0.160) and unstable conditions (d=1.988 vs. 0.029), while Y-balance showed similar changes. Muscle morphology showed greater increases in resistance exercise+neuromuscular electrical stimulation for the cross-sectional area (d=1.127 vs. 0.070) and thickness (d=0.737 vs. 0.203). Biomarker responses were also larger in resistance exercise+neuromuscular electrical stimulation. Overall, the neuromuscular electrical stimulation was associated with favorable trends across several functional and clinical outcomes.