Medial condyle hypoplasia in adolescent and young adult patients with trochlear dysplasia: a retrospective study.

OBJECTIVE: To determine the association between medial femoral condyle hypoplasia and trochlear dysplasia by analyzing the knee magnetic resonance imaging scans of young patients with or without trochlear dysplasia.

MATERIALS AND METHODS: This was a retrospective analysis of magnetic resonance imaging scans of the knees of young individuals (16-35 years of age): 30 patients with trochlear dysplasia and 30 individuals with no signs of patellofemoral instability. The ratios between the depth, width, and height of the medial and lateral femoral condyles (dLC/dMC, wLC/wMC, and hLC/hMC, respectively) were calculated, as was the ratio between the width of the medial condyle and the total width of the femur (wMC/FW). All of the values were determined in consensus by two radiologists.

RESULTS: We evaluated 60 patients: 30 with trochlear dysplasia and 30 without. The mean dLC/dMC, wLC/wMC, and hLC/hMC ratios were higher in the patients than in the controls ( p < 0.05), whereas the mean wMC/FW ratio was lower in the patients ( p < 0.05). The optimal cutoff values, obtained by calculating the areas under the receiver operating characteristic curves, were 1.0465 for the dLC/dMC ratio (76% sensitivity and 63.3% specificity), 0.958 for the wLC/wMC ratio (80% sensitivity and 73.3% specificity), and 1.080 for the hLC/hMC ratio (93.3% sensitivity and 93.3% specificity).

CONCLUSION: Our findings confirm our hypothesis that trochlear dysplasia is associated with medial condyle hypoplasia.