Effect of Open Kinetic Chain Knee Extension Exercises With Neuromuscular Electrical Stimulation in Patients With Post-Acl Reconstruction Surgery

Background: Anterior cruciate ligament (ACL) reconstruction is a common orthopedic procedure aimed at restoring knee stability following ligament rupture. Despite surgical success, persistent quadriceps weakness, limited range of motion, and delayed functional recovery remain key rehabilitation challenges. Open kinetic chain (OKC) exercises are frequently used to restore muscle strength post-ACL reconstruction; however, the addition of neuromuscular electrical stimulation (NMES) may further enhance outcomes by targeting muscle activation and reducing inhibition. Objective: To determine the effectiveness of combining NMES with OKC knee extension exercises in improving functional performance, range of motion, and patient-reported outcomes following ACL reconstruction. Methods: A randomized clinical trial was conducted with 58 participants, four weeks post-ACL reconstruction, allocated into two groups: Group A (OKC + NMES, n=29) and Group B (OKC only, n=29). Interventions were delivered thrice weekly over eight weeks. Functional performance was assessed using the Single-Leg Hop Test (SLHT), patient-reported outcomes were evaluated via the Lysholm Knee Scoring Scale (LKSS), and range of motion (ROM) was measured using a universal goniometer. Data were analyzed using non-parametric tests, with significance set at p < 0.05. Results: At 8 weeks, Group A showed significantly greater improvements than Group B. SLHT scores increased from 2.48 ± 1.96 cm to 48.66 ± 6.64 cm in Group A, versus 2.03 ± 2.08 cm to 36.97 ± 2.67 cm in Group B (p < 0.001). LKSS scores improved from 52.93 ± 6.34 to 91.55 ± 4.19 in Group A, and from 50.34 ± 7.78 to 81.06 ± 2.87 in Group B (p < 0.001). Flexion increased to 109.48° ± 10.80 in Group A vs. 90.48° ± 3.90 in Group B (p < 0.001). Full extension (0°) was restored only in Group A (p < 0.001). Conclusion: Combining NMES with OKC exercises significantly enhances post-operative recovery in ACL-reconstructed patients by improving quadriceps function, knee mobility, and subjective outcomes.