Dong C, Zhao C, Li M, et al. - This study was carried out to assess the accuracy of tibial tubercle-trochlear groove distance (TT-TG) and tibial tubercle-posterior cruciate ligament distance (TT-PCL) in consideration of the mild and severe trochlear dysplasia. Researchers retrospectively examined MRI findings of consecutive knee joints with PFI symptoms diagnosed in our hospital between 2015 and 2020. Researchers included 20 cases of type A (mild trochlear dysplasia); 20 cases of type B, C, and D (severe trochlear dysplasia); and 20 cases of normal type and divided them into normal group (normal trochlea), mild group (type A), and severe group (type B, type C, type D). The inter-observer and intra-observer correlations of TT-TG measurements decreased in the group of severe dysplastic trochlea in comparison with the mild trochlear dysplasia. For patients with low-grade trochlear dysplasia, the determination of TT-TG and TT-PCL distance are of great significance in the present study. In patients with severe dysplastic trochlea, TT-PCL, without referring to the abnormal trochlear groove, is an effective indicator to measure the lateralization of tibial tuberosity.