Dynamic US study in the evaluation of infants with vertical or oblique talus deformities

Abstract

Congenital vertical talus (CVT) is a rare foot deformity that is sometimes difficult to differentiate from oblique talus (OT) by physical examination and foot radiography. The purpose of this study was to summarize our experience with US in evaluation of CVT and OT deformities. We identified all children (2005-2011) younger than 6months who underwent dynamic focused US of the foot at our tertiary-care facility to evaluate clinically equivocal cases of CVT. Diagnostic criteria for CVT were persistent talonavicular dislocation on forced plantar flexion of the foot. OT was diagnosed based on reduction of the talonavicular dislocation on forced plantar flexion. Medical and imaging charts were reviewed for diagnosis on US and plain radiographs (when available) and for underlying neuromuscular disorders, treatment and outcome on follow-up. Ten patients (eight boys and two girls, mean age 33days) were evaluated by US for CVT. Radiographs of the foot were obtained in only two children and were non-diagnostic. Thirteen feet were evaluated by US. Diagnosis of CVT was confirmed by surgery in seven children, three of whom had bilateral CVT. Diagnosis of OT in three children was supported by response to casting treatment. Dynamic US can reliably distinguish between CVT and OT deformities.