Increased internal tibiofemoral rotation is associated with anterolateral ligament injury and high-grade pivot-shift in ACL-injured patients

Purpose: To evaluate whether tibiofemoral rotation is associated with a concurrent anterolateral ligament (ALL) injury and pivot-shift grading in patients with a primary anterior cruciate ligament (ACL) tear. Methods: In this multicenter cross-sectional study constituting a secondary analysis of previous studies, medical records and magnetic resonance imaging (MRI) scans of patients with unilateral primary ACL injury were reviewed. Demographics and pivot-shift grading were collected. ALL was identified on MRI coronal images and categorized as intact or injured. Tibiofemoral rotation angle (TFA) was measured on axial MRI. Optimal TFA cut-off associated with ALL injury was identified by a receiver operating characteristic (ROC) curve. Results: Of 206 included patients, 152 (73.8%) exhibited signs of ALL injury. Pivot-shift tests were predominantly graded as 2 (71.4%), and notably, all Grade 3 pivot-shift assessments were associated with ALL injury. Mean TFA was significantly higher in cases with ALL injury (5.2 +/- 3.6 degrees) compared to intact ALL cases (2.7 +/- 3.5 degrees; p < 0.001). A positive correlation was observed between pivot-shift grading and TFA (r = 0.204, p = 0.003). Optimal TFA cut-off value, based on the absolute measurement, for predicting ALL injury was 2.5 degrees (sensitivity: 0.77; specificity: 0.55). Patients with TFA >= 2.5 degrees had a significantly higher risk of ALL injury (odds ratio: 3.34, 95% confidence interval [CI]: 1.74-6.42, p < 0.001); when combined with pivot-shift Grade 2 or 3, this risk substantially increased to 13.68 (95% CI: 6.29-29.84, p < 0.001). Conclusion: Higher TFA was associated with an increased prevalence of ALL injuries and a high-grade pivot-shift in ACL-deficient patients. Patients with a TFA >= 2.5 degrees showed a threefold higher likelihood of ALL injuries, and this risk further escalated with a higher-grade pivot-shift.