The significance of magnetic resonance imaging in severe femoral trochlear dysplasia assessment

The clinical diagnosis of femoral trochlear dysplasia primarily relies on imaging. In the past, plain imaging was the major source of diagnosis. The present study investigated the application of magnetic resonance imaging (MRI) in the objective assessment of severe femoral trochlear dysplasia. A retrospective analysis was performed on knee MRIs from 30 normal subjects (30 knees) and 59 patients (61 knees) with severe femoral trochlear dysplasia based on the Dejour morphological classification. Cartilage and subchondral bone landmarks were used to compare a series of measurements between patient and control groups. These measurements included the femoral trochlear groove depth, sulcus angle, the lateral trochlear inclination, trochlear facet asymmetry, the femoral medial and lateral condyle symmetry, and the ratios between the femoral medial/lateral condyles and the maximal trochlear width. The measurement values based on the two types of landmarks were also compared within the patient and control groups, separately. In addition, the femoral trochlear groove depth, sulcus angle, lateral trochlear inclination and trochlear facet asymmetry of patients with different Dejour types were compared. Significant differences were observed in the femoral trochlear groove depth, sulcus angle, lateral trochlear inclination and trochlear facet asymmetry between the patient and control groups (P<0.05). Based on the two types of landmark, all indexes were significantly different (P<0.05; with the exception of lateral trochlear inclination) between the patient and control groups. Among patients with various Dejour types, the femoral trochlear groove depth, sulcus angle, lateral trochlear inclination and trochlear facet asymmetry demonstrated no significant differences. MRI exhibited advantages in revealing articular cartilage over conventional radiography and computed tomography. Therefore, cartilage landmarks in MRI images may be utilized to objectively evaluate femoral trochlear dysplasia in patients with severe femoral trochlear dysplasia.