Objective: This study aimed to analyze the ultrasound characteristics of fetal congenital vertical talus (CVT) to provide a detailed basis for the prenatal diagnosis of CVT.
Methods: We retrospectively analyzed the ultrasonographic findings of fetuses with CVT confirmed by X-ray, surgery, or autopsy from 2010 to 2020. Clinical characteristics and ultrasonographic findings of CVT, including foot morphology, ossification center of the calcaneus and talus, associated deformities, and chromosomal test results, were recorded.
Results: Thirteen patients diagnosed with CVT by prenatal ultrasound were confirmed postpartum. Nine cases were bilateral, and four were unilateral. Under two-dimensional ultrasound, 13/13 cases had abnormal foot morphology, and 10 of 13 cases (76.9%) showed that the ossification center of the talus moved downward, and the calcaneus moved laterally. Under three-dimensional ultrasound, 11 cases (84.6%) presented a "rocking chair" appearance, and two cases did not obtain satisfactory three-dimensional image due to oligohydramnios and fetal position. In this group of cases, two cases (15.4%) were isolated CVT, and the other 11 cases (84.6%) were complicated with other abnormalities. Eleven cases of non-isolated CVT and 1 case of isolated CVT were induced, and another patient with isolated CVT had undergone postnatal surgery, which had been followed up for 8 years and recovered well.
Conclusions: The combination of fetal foot morphology, ossification center position of the calcaneus and talus, and three-dimensional ultrasound can provide a reliable diagnosis of CVT. Furthermore, we should pay more attention to the evaluation of other systemic and chromosomal abnormalities in CVT cases.
Keywords: Congenital vertical talus; fetus; ossification center; prenatal diagnosis; ultrasound.