Impact of Anterolateral Ligament Femoral Tunnel Orientation on Tunnel Collision and Clinical Outcomes in Combined ACL and ALL Reconstruction

Abstract

Background: Tunnel collision during ligament surgery may impact graft integrity and fixation, potentially influencing surgical outcomes. Identifying the optimal anterolateral ligament (ALL) femoral tunnel orientation is therefore important to improve the overall success of combined anterior cruciate ligament (ACL) reconstruction (ACLR) and ALL reconstruction (ALLR). Purpose: To investigate whether the orientation of the ALL femoral tunnel in combined ACLR and ALLR affects the risk of femoral tunnel collision and subsequent clinical outcomes. Study Design: Cohort study; Level of evidence, 3. Methods: Medical records of patients who underwent combined ACLR and ALLR from 2018 to 2022 were reviewed, and those with at least 2 years of follow-up were evaluated. Patients were classified based on the orientation of the ALL femoral tunnel as targeted at the time of surgery, with tunnels created at 30 degrees axial and 30 degrees coronal (Group P) or 0 degrees axial and 240 degrees coronal (Group D). Between-group comparisons were conducted for radiological parameters-including the characteristics of the ACL and ALL femoral tunnels, tunnel collision rates, minimal distance between the tunnels (MDBT), and collision volumes-assessed using 3dimensional knee models from postoperative computed tomography scans. In addition, functional scores, knee laxity, and intraoperative data were analyzed. Results: A total of 64 patients were included. Group D exhibited a significantly lower tunnel collision rate compared with group P (68.8% and 6.3% in groups P and D, respectively; P < .001), along with a larger MDBT (-5.5 +/- 2.5 mm and 3.7 +/- 4 mm in groups P and D, respectively; P < .001) and a smaller collision volume (92.2 +/- 89.5 mm(3) and 1.2 +/- 3.5 mm(3), respectively; P < .001). No significant differences were observed between groups in functional scores or knee laxity at the final follow-up. However, the surgical time for cases without combined meniscal procedures was significantly longer in group P (P = .025). Additional comparative analysis newly categorized by tunnel collision also revealed no differences regarding the surgical outcomes; however, surgical time was significantly longer in cases where tunnel collision occurred (P < .001 for both the overall cohort and cases without combined meniscal procedures). Conclusion: Distally directed drilling for the ALL femoral tunnel reduced the risk of tunnel collision in combined ACL and ALL procedures without compromising clinical outcomes. Although the tunnel collision itself did not affect surgical outcomes, distal drilling significantly reduced surgical time by minimizing collision risk, thereby optimizing the surgical process.