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 ( < 0.05), whereas the mean wMC/FW ratio was lower in the patients ( < 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.