All mothers were examined prenatally in a multidisciplinary clinic for fetal abnormalities. Postnatal outcome was obtained by chart review (24) or telephone interview (24) and feet were classified as Normal (N), Positional Deformity (PD), Isolated Clubfoot (ICF) and Complex Clubfoot (CCF).
Post natal clubfoot was found in 73 feet in 40 children giving a positive predictive value (PPV) of 85%. Accuracy of specific diagnosis was significantly lower – 65% initially and 75% at final US. No post natal CCF had been undiagnosed and inaccuracies were all overdiagnoses. 24 kariotypes were performed. Three were abnormal but had additional US findings and had been classified as CCF. No abnormal kariotypes were found in fetuses diagnosed as ICF.
The prenatal diagnosis of clubfoot carries a positive predictive value of 87% with lower values of ICF (76%) and CCF (69%). The diagnostic accuracy increases with follow up ultrasound examinations which should be performed periodically. The most problematic diagnosis to rule out is arthrogryposis and further diagnostic modalities should be researched. When Isolated Clubfoot is diagnosed, the indication for amniocentesis and kariotyping is questionable.
Club foot was diagnosed by ultrasonography in 91 feet (52 fetuses) at a mean gestational age of 22.1 weeks (14 to 35.6). Outcome was obtained by chart review in 26 women or telephone interview in 26. Feet were classified as normal, positional deformity, isolated club foot or complex club foot. At initial diagnosis, 69 feet (40 fetuses) were classified as isolated club foot and 22 feet (12 fetuses) as complex club foot. The diagnosis was changed after follow-up ultrasound scan in 13 fetuses (25%), and the final ultrasound diagnosis was normal in one fetus, isolated club foot in 31 fetuses, and complex club foot in 20 fetuses. At birth, club foot was found in 79 feet in 43 infants for a positive predictive value of 83%. Accuracy of the specific diagnosis of isolated club foot or complex club foot was lower; 63% at the initial ultrasound scan and 73% at the final scan. The difference in diagnostic accuracy between isolated and complex club foot was not statistically significant. In no case was postnatal complex club foot undiagnosed on fetal ultrasound and all inaccuracies were overdiagnoses. Karyotyping was performed in 25 cases. Abnormalities were noted in three fetuses, all with complex club foot and with additional findings on ultrasound.
