Influence of Intra-Articular Tunnel Aperture Morphology on Clinical Outcomes and Graft Rerupture After ACL Reconstruction

<b>Background/Objectives:</b> Variations in drill orientation during femoral and tibial tunnel creation can alter intra-articular tunnel aperture morphology in anterior cruciate ligament (ACL) reconstruction. Enlarged or irregular apertures may affect graft-tunnel conformity and graft mechanics. This study aimed to assess the relationship between intra-articular femoral and tibial tunnel aperture areas, postoperative clinical outcomes, and graft rerupture. This study specifically focuses on MRI-based measurement of intra-articular tunnel aperture area, a morphological parameter that has not been routinely evaluated in previous ACL reconstruction studies and differs conceptually from tunnel diameter or drilling angles. <b>Methods:</b> This retrospective case-control study included patients who underwent primary ACL reconstruction with an 8 mm hamstring autograft using the anteromedial portal technique. All patients completed a minimum 2-year follow-up and postoperative MRI. Femoral and tibial intra-articular aperture areas were measured on MRI Clinical outcomes (Lysholm scores and KOOSs) in patients with intact grafts. Patients were categorized into intact-graft and rerupture groups. Correlation analyses were used to evaluate associations between aperture areas and clinical outcomes. Logistic regression identified predictors of rerupture. <b>Results:</b> A total of 152 patients met the inclusion criteria, including 13 with graft rerupture. In the intact-graft group, mean femoral and tibial aperture areas were 127.34 ± 8.92 mm² and 138.33 ± 7.08 mm², respectively. Both aperture areas demonstrated significant negative correlations with Lysholm scores and KOOSs. Patients with rerupture had significantly larger femoral (145.26 ± 4.22 mm²) and tibial (158.02 ± 2.88 mm²) aperture areas (<i>p</i> < 0.001 for both). Logistic regression identified tibial aperture area as a significant predictor of rerupture. <b>Conclusions:</b> Larger intra-articular tunnel aperture areas were associated with inferior functional outcomes, and increased tibial aperture area correlated significantly with graft rerupture. Aperture morphology may represent an important factor influencing graft integrity and postoperative recovery after ACL reconstruction.