Combined Anterior Cruciate Ligament (ACL) and Anterolateral Ligament Reconstruction Versus Isolated ACL Reconstruction: A Propensity Score-matched Cohort Study

Background: Residual rotational laxity and graft failure after isolated anterior cruciate ligament reconstruction (ACLR) remain major challenges. Anterolateral ligament reconstruction (ALLR) may enhance rotational control and reduce graft failure. Objective: This study compared functional and stability outcomes between combined ACLR + ALLR and isolated ACLR using a propensity score-matched design. Materials and Methods: In this retrospective cohort study, 72 matched patients (36 per group) undergoing primary ACLR ± ALLR were analyzed. Matching was based on age, sex, body mass index, chronicity, baseline International Knee Documentation Committee (IKDC) score, meniscal status, and surgeon using 1:1 nearest-neighbor matching (caliper = 0.2 standard deviation). Functional outcomes (IKDC, Lysholm, Tegner, and anterior cruciate ligament-return-to-sport index) and stability (pivot shift and KT-1000) were assessed at 6, 12, and 24 months. Between-group differences were compared using paired tests, effect sizes, and 95% confidence intervals (CIs). Results: At 24 months, the ACLR + ALLR group showed higher IKDC (92.4 ± 3.2 vs. 88.6 ± 5.1; mean difference: 3.8; 95% CI: 1.7–5.9; P = 0.001) and Lysholm scores (94.2 ± 3.8 vs. 90.5 ± 4.6; P = 0.003). Residual pivot shift (≥grade 1) was significantly lower in ACLR + ALLR (5.6%) than ACLR alone (27.8%; absolute risk reduction 22.2%; 95% CI: 5.4–39.0; P = 0.031). Graft failure occurred in 0/36 (0%) versus 6/36 (16.7%), respectively (Fisher’s exact P = 0.01). Return to pre-injury sport occurred in 89% versus 64% ( P = 0.02). No major complications or stiffness were reported. Conclusion: Combined ACLR + ALLR was associated with improved rotational stability and functional outcomes, with a lower observed graft failure rate compared with isolated ACLR. However, given the observational design and small number of failure events, these findings should be interpreted cautiously.