Objective: Since prenatal diagnosis of isolated clubfoot has a false positive rate (FP) of 10%-40%, fetal parameters that might correlate with post-natal confirmation and grade of severity were investigated. Method: Retrospective analysis (2013-2019) of cases analysed with threedimensional multiplanar view. The following data were recorded: the angle between the long axis of foot and lower leg; width, length and width-to-length ratio (W/L) of the foot; tibia length and calf width (T/C) ratio. Severity after birth was assessed using the Pirani classification. Results: Diagnosis was confirmed in 45/53 neonates (84.9%, FP 15%). Values were higher for both angle and W/L in true vs false positive cases (median angle 100.4 versus 69.55 , p <.000; median W/L 0.53 vs 0.45, p = .001), no difference for T/C (3.77 vs 3.48, p = .8). The area under the curve for angle was 0.98 (CI 0.94-1.00), with a diagnostic cutoff of 84.7 (PPV of 100%, NPV of 66.7%). Median Pirani score, available for 33 neonates (73.3%) was 3 (IQR 3-4): only angle correlated with Pirani score (Spearman coefficient 0.36, p = .04) Conclusion: Measuring the angle between the foot and lower leg can reduce the FP rate of prenatal congenital clubfoot diagnosis and better predict the need for postnatal treatment.

No abstract

No abstract