Stumetz KS, Gothard MD, Walser RF, et al. - In this research, variations in the tibial tubercle-trochlear groove (TT-TG) and patellar tendon-posterior cruciate ligament (PT-PCL) distances were evaluated in symptomatic patients with non-contact internal knee derangements (IKD) and symptomatic patients with internally intact knees (control). Researchers designed a retrospective review of MRI studies to compare 78 patients with meniscal and ligamentous derangements of the knee to 63 internally intact knees (age range, 13 to 50 years). Two board-certified radiologists independently reviewed MRI findings to evaluate for agreement. They assessed TT-TG and PT-PCL distances on proton density-weighted axial images by two independent observers blinded to the MRI and arthroscopic findings. Differences in TT-TG distance between the internal derangement and control groups were ascertained using independent t tests. Using Chi-square tests, categorical variables for distributional equality between study groups were compared. The results of this research reveal that increased TT-TG distances and PT-PCL distances are correlated with both cartilaginous and ligamentous internal knee injuries, with TT-TG distances greater than the 12 mm representing a new threshold for concern.