MRI findings of femoral trochlear and patellar dysplasia

Objective: To investigate the MRI findings of patellar and femoral trochlear dysplasia. Methods: 30 knee MRI studies of 26 consecutive patients with patellofemoral disorders were reviewed and compared with 30 MRI examinations of 30 healthy volunteers. The tibial tubercle-trochlear groove distance (TT-TG), ventral trochlear prominence, ratio of internal and external trochlear facets, lateral patellofemoral angle, Wiberg classification for patellar shape and Wiberg index were determined on the axial images at 3 cm above the femorotibial joint. Independent-samplet test with IBM SPSS 18.0 software package was used for statistical analysis. Results: There were significant differences in the TT-TG (P = 0.02), ventral trochlear prominence (P = 0), lateral patellofemoral angle (P = 0), ratio of internal and external trochlear facets (P = 0.01), and patellar Wiberg indexes (P = 0) between patellofemoral disorders and normal knees as well as between Wiberg I-II and Wiberg III-IV (P = 0). The patellar Wiberg indexes were inversely correlated with the trochlear and patellar shapes whereas the trochlear shapes were positively correlated with patellar shapes. Conclusion: Axial MRI is useful for assessing patellar and femoral trochlear dysplasia. (authors)