Evaluation of the effectiveness of the diagnosis of patellar malalignment of the ratio of medial patellar distance to lateral patellar distance by magnetic resonance imaging

Patellofemoral problems develop in young and physically active individuals. A large number of measurements have been described with different imaging methods for trochlear dysplasia, abnormal lateralization in the tibial tubercle, and patella alta, which are the main factors in the etiology of malalignment disorders. MRI is widely used in patellofemoral joint problems because of its high soft tissue resolution and does not contain ionizing radiation. The main aim of this study is to examine the effectiveness of MPM / LPM ratio in demonstrating patellofemoral malalignment. In the study, 200 knee MRIs were evaluated retrospectively by a radiologist experienced in musculoskeletal system and MRI. For each knee, ISI, TT-TG distance, sulcus angle, lateral trochlear inclination angle, LPT angle, MPM, LPM and MPM / LPM ratio were measured. As a result of the measurements, knee MRIs were divided into two groups as those with malalignment and without malalignment. The relationship between MPM / LPM ratio and these measurements was evaluated in both groups. LPM length and MPM / LPM ratio were found to be statistically significant in predicting malalignment. The best diagnostic performance in malalignment when the value for the MPM / LPM ratio was considered above 1.07, the sensitivity was 71.2% and the specificity was 59.4%. Consequently; MPM / LPM ratio, which was defined and used for the first time in our study, has an important potential in patellar instability. However, with prospective studies, the efficiency of MPM / LPM ratio in surgical technique and decision can be evaluated, and MPM / LPM ratio can be calculated in different imaging methods. Keywords: Trochlear dysplasia, patella alta, TT-TG distance, LPT angle, ISI, LTI angle, sulcus angle.