The Effect of Axial Tibiofemoral Rotation on Primary ACL Injury in Professional Soccer Players: A Matched-Cohort Analysis

Background: Recent studies suggest that increased tibiofemoral (TF) rotation elevates the risk of anterior cruciate ligament (ACL) reconstruction failure, with a proposed threshold of 4.5° of internal rotation (IR). However, the role of TF rotation in primary ACL injury remains unclear. Purpose/Hypothesis: The purpose was to evaluate whether axial TF malalignment, as reflected by the TF axial rotation angle and tibial tubercle–trochlear groove (TTTG) distance, is associated with primary ACL injury in professional soccer players. It was hypothesized that increased internal TF rotation is associated with ACL injury. Study Design: Cross-sectional study. Methods: A retrospective review was performed on a consecutive series of professional soccer players who underwent ACL reconstruction between January 2012 and August 2024. Inclusion criteria were primary ACL injury and availability of preinjury magnetic resonance imaging (MRI). Cases were matched 2:1 by age with controls, who were players who underwent meniscal surgery during the same period and had no history of ACL injury. The groups were compared in terms of age, TTTG distance, medial and lateral posterior tibial slope, resting knee flexion, and axial TF rotation during MRI acquisition. All MRI scans were independently reviewed by 2 musculoskeletal radiologists. Results: Twenty-four professional soccer players (mean ± SD age, 25.3 ± 4.2 years) with MRI and arthroscopy-confirmed primary ACL injuries were included. The control group consisted of 48 players (mean age, 23.6 ± 3.3 years) who had intact ACLs confirmed via MRI and arthroscopy and underwent meniscal surgery. No statistically significant differences were observed between groups for age, medial and lateral posterior tibial slope, knee flexion during MRI, or axial TF rotation (IR, 6.7°± 5.8° vs 4.3°± 5.9°; all, P > .05). The prevalence of resting axial TF rotation ≥4.5° of IR was also not significantly different between groups (70.8% vs 66.7%; P = .721). The TTTG distance was significantly smaller in players with ACL injuries (8.9 ± 3.4 mm vs 10.9 ± 4.2 mm; P = .050) but did not reach statistical significance when adjusted for knee flexion (odds ratio, 1.15; 95% CI, 1.00-1.32; P = .059). There was no difference in resting axial TF rotation and TTTG between pre- and postinjury MRI scans in players with ACL injury. Conclusion: In this cohort of professional soccer players, TF axial rotation was not significantly associated with primary ACL injury. Although not statistically significant, the association between a smaller TTTG distance and ACL injury may reflect an underlying anatomic predisposition related to IR malalignment. Notably, neither resting axial TF rotation nor TTTG distance differed before and after injury, indicating that these features are likely inherent.