Effects of Neuromuscular Electrical Stimulation After Anterior Cruciate Ligament Reconstruction on Quadriceps Strength, Function, and Patient-Oriented Outcomes: A Systematic Review

STUDY DESIGN: Systematic literature review. OBJECTIVE: To perform a systematic review of randomized controlled trials assessing the effects of neuromuscular electrical stimulation (NMES) on quadriceps strength, functional performance, and self-reported function after anterior cruciate ligament reconstruction. BACKGROUND: Conflicting evidence exists regarding the effectiveness of NMES following anterior cruciate ligament reconstruction. METHODS: Searches were performed for randomized controlled trials using electronic databases from 1966 through October 2008. Methodological quality was assessed using the Physiotherapy Evidence Database Scale. Between group effect sizes and 95% confidence intervals (Cls) were calculated. RESULTS: Eight randomized controlled trials were included. The average Physiotherapy Evidence Database Scale score was 4 out of possible maximum 10. The effect sizes for quadriceps strength measures (isometric or isokinetic torque) from 7 studies ranged from -0.74 to 3.81 at approximately 6 weeks postoperatively; 6 of 11 comparisons were statistically significant, with strength benefits favoring NMES treatment. The effect sizes for functional performance measures from 1 study ranged from 0.07 to 0.64 at 6 weeks postoperatively; none of 3 comparisons were statistically significant, and the effect sizes for self-reported function measures from 1 study were 0.66 and 0.72 at 12 to 16 weeks postoperatively; both comparisons were statistically significant, with benefits favoring NMES treatment. CONCLUSION: NMES combined with exercise may be more effective in improving quadriceps strength than exercise alone, whereas its effect on functional performance and patient-oriented outcomes is inconclusive. Inconsistencies were noted in the NMES parameters and application of NMES. LEVEL OF EVIDENCE: Therapy, level 1a-. J Orthop Sports Phys Ther 2010;40(7):383-391. doi:10.2519/jospt.2010.3184