CT-Based Tunnel Position Analysis and its Correlation with Residual Instability after Anterior Cruciate Ligament Reconstruction.

INTRODUCTION: Anterior cruciate ligament (ACL) reconstruction aims to restore knee stability, but improper femoral and tibial tunnel placement can lead to persistent instability. Computed tomography (CT)-based 3D assessment helps correlate tunnel position with outcomes. MATERIALS AND METHODS: A study of 50 patients undergoing primary arthroscopic ACL reconstruction used post-operative CT to assess tunnel placement relative to anatomical landmarks. Knee stability was evaluated using Lachman and pivot shift tests, and patients were grouped by residual instability. RESULTS: Residual instability occurred in 36% of patients. Anatomical femoral and tibial tunnel placement was achieved in 62% and 68% of cases, respectively. Non-anatomical femoral (66.7%) and tibial (55.6%) tunnels were more common in unstable knees, with combined malposition showing the highest instability rates. CONCLUSION: Non-anatomical tunnel placement, especially femoral, is strongly associated with residual instability, emphasizing the importance of precise anatomical positioning in ACL reconstruction.