Influence of medial and lateral imaging plane inclination on assessment of trochlear depth, sulcus angle, and facet asymmetry in the setting of trochlear anatomy: a cadaveric study.

PURPOSE

(1) to assess the influence of medial or lateral imaging plane inclination on the measurement of sulcus angle, trochlear depth, and facet asymmetry on transverse cross-sectional images. (2) to assess the effect of measurement level (height) on these respective parameters.

MATERIALS AND METHODS

Twenty dry femurs (9 left, 11 right) were imaged with CT. A 3D dataset was obtained from which axial images were reconstructed in the ideal plane without inclination as well as with 8° of medial and lateral inclination. Sulcus angle, trochlear depth, and facet asymmetry were measured on the 3 image sets. In addition, the measurements were performed at 5 mm and 10 mm from the superior margin of the medial trochlear facet. Statistical analysis consisted of the Wilcoxon test and calculation of measurement variation.

RESULTS

There were no statistically significant differences between the indicated measurements on the reference set compared to medial or lateral inclination. All measurements were significantly different depending on measurement height.

CONCLUSION

Medial or lateral inclination in the transverse imaging plane of 8° does not influence the values of typical parameters used for the assessment of trochlear dysplasia. The measurement height has a significant influence, and a consensus should be found as to which is the optimal measurement height.