Evaluation of anatomical and operative factors affecting graft healing in anterior cruciate ligament reconstruction

Objective: In this retrospective study, it was aimed to evaluate the anatomical and operative factors affecting graft healing after single bundle anatomical Anterior Cruciate Ligament (ACL) Reconstruction (ACLR) with hamstring autograft. Material and Method: A total of 94 patients with minimum 18 months follow-up who underwent single-bundle ACLR with hamstring autograft between 2016 and 2019 years were included in this study. Graft healing was quantitatively evaluated at 1 year on magnetic resonance imaging (MRI) scan as the mean Signal/Noise Ratio (SNQ) measured from 3 regions on the graft. Potential factors that may affect graft healing; age, gender, body mass index, time from injury to surgery, medial and lateral tibial slope, lateral femoral condylar ratio, intercondylar notch index, partial meniscectomy, ACL remnant preservation, femoral and tibial tunnel aperture localization, graft diameter, graft bending angle and graft/notch volume ratio were evaluated separately and correlations with 1st year SNQ were determined by univariate and multivariate regression analysis. IKDC (International Knee Documentation Committe), Lysholm and Marx activity scale score were used in clinical evaluation. The relationship of graft healing with clinical and functional results at the first year and at the last follow-up was evaluated. Results: Univariate regression analysis showed that a medial (p <0.001) and lateral tibial slope (p <0.001), intercondylar notch index (p = 0.016), ACL remnant preservation (p <0.001), high femoral tunnel (p = 0.011), anteriorly located tibial tunnel (p = 0.005), graft bending angle (p = 0.005), and graft / intercondylar notch volume ratio (p <0.001) were all statistically significantly correlated with mean SNQ values. A multivariate regression analysis showed 3 independent significant factors: Lateral tibial slope (p = 0.002), ACL remnant preservation (p <0.001), graft/notch volume ratio (p <0.001). In addition, a weak correlation was observed between 1 year SNQ values and Marx activity score (p = 0.031) and femoral integration grade (p = 0.004). There was no significant correlation between other clinical and radiological results. Conclusion: Lateral tibial slope, ACL remnant preservation and graft/notch volume ratio appeared to have a significant influence on graft healing as assessed on 1-year MRI scan after ACLR. Also, a weak correlation of graft healing with Marx activity score and femoral tunnel integration was found.