The Role of Ultrasound in Clubfoot Treatment: Correlation with the Pirani Score and Assessment of the Ponseti Method

Abstract

To evaluate neonates and infants with clubfoot, clinical and imaging modalities are required. Conventional radiography is of limited value because the studied bones are not fully ossified. We attempted to (1) evaluate clinically and sonographically the reliability of the Ponseti method in correcting clubfeet; and (2) determine whether various ultrasound (US) variables correlated with each other and with the Pirani score before and after treatment. We prospectively followed 17 infants (25 clubfeet) assessed using the Pirani score and US variables (medial malleolus navicular distance, navicular alignment in relation to the talar head, medial soft tissue thickness, talar length, and calcaneocuboid distance) and treated with the Ponseti method. The mean age of the patients at first casting was 30 days, and repeat assessment after treatment was performed at a mean age of 6.3 months. Patients were followed for a minimum of 0.75 months (mean, 14.1 months; range, 0.75-38 months). The Ponseti method corrected all feet. We found three clinical/US correlations. Before treatment, we observed a negative correlation between the clinical midfoot score and the sonographic medial malleolus navicular distance. After treatment we observed two negative correlations: one between the midfoot score and the sonographic talar length and the other between the hindfoot score and medial malleolus navicular distance. Four feet had recurrence of varus, two of which had an increased calcaneocuboid distance despite full restoration of navicular alignment in one foot. US can play a role in clubfoot assessment and may alert the surgeon to feet that may be prone to recurrence. Level II, prospective study. See Guidelines for Authors for a complete description of levels of evidence.