Muscle volume evaluation using 3DCT for congenital clubfoot

In congenital clubfoot, the lower leg is very thin and the calf muscles are hypoplasic. However, there are few studies reporting real muscle volume.

The purpose of this study is to assay the muscle volume in congenital clubfoot using 3DCT and to quantify the degree of the hypoplasia.

From January 2015 to December 2016, nine consecutive patients, seven male and two female, with unilateral congenital clubfeet were recruited for CT scans. Axial transverse sectional CT scans were acquired from the delineation of the fibular head to the tibial plafond. From the data, we rendered the entire muscle in 3D for muscle volume assay, and further segmented the posterior musculature for comparison between the normal and affected sides.

The whole muscle volume on the normal side was 291.23 cm³ (181.23-593.49) and that on the affected side was 225.08 cm³ (120.71-429.08), for an affected side to normal side ratio of 0.79 (0.72-0.9), which was significantly smaller (p < .01). Posterior muscle volume on the normal side was 175.81 cm³ (103.72-376.32) and that on the affected side was 106.52 cm³ (58.3-188.39). The ratio of posterior muscle to whole muscle on the normal side was 0.62 (0.46-0.75), and that on the affected side was 0.48 (0.4-0.55), such that the affected side was significantly smaller (p < .01).

This study contributes quantitative data supporting the longstanding observations that the posterior calf muscles are significantly smaller on the affected side compared to the normal side in congenital clubfoot, and further underscores the importance of the extending the excursion of these muscles.