According to a recent retrospective review published in Journal of Orthopaedic Surgery and Research, the increased tibial tubercle-trochlear groove (TT-TG) and patellar tendon-posterior cruciate ligament (PT-PCL) distances are linked with both cartilaginous and ligamentous internal knee injuries, with TT-TG distances greater than the 12 mm pointing towards a chronic knee disorder, internal knee derangements (IKD).

Kyle S Stumetz et al. examined differences in the TT-TG and PT-PCL distances in symptomatic patients with non-contact internal knee derangements (IKD) and with internally intact knees (control).

Seventy eight patients with meniscal and ligamentous derangements of the knee were compared to 63 internally intact knees (aged 13-50 years). Two board-certified radiologists individually reviewed the MRI findings. Two observers individually calculated the TT-TG and PT-PCL distances on proton density-weighted axial images blinded to the MRI and arthroscopic findings. Differences in TT-TG distance between the internal derangement and control groups were verified via independent t tests. The categorical variables for distributional equality between study groups were distinguished via Chi-square tests.

It was found that the mean TT-TG distance in the IKD group was 11.5 mm (average) than 8.3 mm in the control. Likewise, mean PT-PCL distance was 20.6 mm for the IKD group than 18.2 mm for control. Along with meniscal and cruciate findings, 51 meniscal tears, 12 cruciate ligament tears, and 15 tears were observed in IKD group. Amongst both groups, IKD was significantly correlated with greater TT-TG distance and PT-PCL distance.