Accuracy of Femoral Tunnel Placement between Anteromedial and Anterolateral Visualisation Portals in Anterior Cruciate Ligament Reconstruction - Outcomes of a CT based Cross-Sectional Study.

Introduction: Anatomical femoral tunnel placement is critical for anterior cruciate ligament reconstruction (ACLR). Tunnel placement may vary with different surgical techniques. The aim of this study was to compare the accuracy of femoral tunnel placement between the Anteromedial (AM) and Anterolateral (AL) visualisation portals on post-operative CT scans among a cohort of ACLR patients.

Materials and methods: This cross-sectional study was conducted from January 2018 to March 2020 after obtaining ethics clearance. Patients who went for arthroscopic ACLR in our institute were divided into an AM (group 1) and an AL (group 2) based on the visualisation portal for creating the femoral tunnel and a 3D CT scan was done. The femoral tunnel position was calculated in deep to shallow and high to low direction using the Bernard Hertel grid. Femoral tunnel angle was measured in the 2D coronal image. Statistical analysis was done with the data collected.

Results: Fifty patients with an average age of 26.36 (18-55) years ±7.216 SD were enrolled in the study. In this study, the AM technique was significantly more accurate (p<0.01) than the AL technique in terms of femoral tunnel angle. Furthermore, the deep to the shallow position was significantly (p= 0.018) closer to normative values, as determined by the chi-square test. The chances of error in tunnel angle in femoral condyle are 2.6 times greater in the AL technique (minimal clinical difference).

Conclusion: To conclude, in ACLR the anteromedial visualisation portal can facilitate accurate femoral tunnel placement compared to the anterolateral visualisation portal.