Fourty one patients with ACL-deficient knees were randomized to receive either double-bundle ACL reconstruction (n=21) or triple-bundle ACL reconstruction (n=20). The primary outcome was tibial tunnel enlargement assessed using 3D CT at 2 weeks and 1 year postoperatively. Secondary outcomes included tunnel coalition rates, tunnel position changes, and clinical outcomes such as range of motion and knee stability. Overall, the results revealed that the tunnel enlargement rates in the medial and lateral anteromedial bundles were significantly smaller in the TB-ACLR group compared to the DB-ACLR group (p-values ranging from 0.02 to <0.01), with no significant difference in tunnel coalition or clinical outcomes. The findings suggest that TB-ACLR may provide a biomechanical advantage by reducing tunnel enlargement.