No Difference in Tibial Tubercle Trochlear Groove Distance Between Patients With and Without a History of Anterior Cruciate Ligament Tears

Background: The tibial tubercle–trochlear groove (TT-TG) distance is a known risk factor for patellar instability, but its role in anterior cruciate ligament (ACL) deficiency is unclear. Previous studies found an increased TT-TG distance in patients with noncontact ACL tears compared with patients with intact ACLs. Hypothesis: The authors hypothesize that there will be a significantly increased TT-TG distance in patients with ACL injury compared with patients without ACL injury. Study Design: Cross-sectional study; Level of evidence, 3. Methods: All patients aged 18 to 50 years who had noncontact ACL tears between 2020 and 2021 were included in this study. Patients with ACL tears were compared with a similar cohort of patients with meniscal tears, matched for age and sex, between 2020 and 2021. Patients were excluded if preoperative magnetic resonance imaging (MRI) was unavailable. One author reviewed axial images to measure TT-TG distance. An independent 1-tailed t test was used to assess for a difference in TT-TG distance between patients with and without ACL injury. Results: The TT-TG distance was measured for 299 patients, of whom 159 had an ACL injury and 140 patients had intact ACLs. Patients with an ACL injury had a mean TT-TG distance of 11.3 ± 4.10 mm, and patients without ACL injury had a mean TT-TG distance of 11.9 ± 4.62 mm. There was no significant difference in TT-TG distance between the 2 groups (P = .246). The sample of patients in both groups had no significant differences in age, sex, or laterality of injury. Conclusion: No statistically significant difference in TT-TG distance was found between patients with and without ACL injury. The findings of this study do not support an association between TT-TG distance and ACL deficiency. Instead, TT-TG distance may vary as a result of ACL injury due to increased laxity in tibial external rotation.