Correlation of radiographic and pedobarograph measurements in planovalgus foot deformity

Planovalgus foot deformity is common in children with cerebral palsy. Several pathologies contribute to the deformity. It begins with the lateral displacement of the navicular and the talar head becomes uncovered and prominent in the medial side of the midfoot. The purpose of this study was to assess the correlation between the radiographic and the pedobarographic measurements and the ability to predict foot pressure components using radiographic measurement. The patient sample included 43 patients with cerebral palsy who were ambulatory and had planovalgus foot deformity (76 feet). Medial midfoot pressure showed correlation with talonavicular uncoverage index, talonavicular angle, medial arch angle, Meary angle, and lateral talocalcaneal angle. Heel impulse showed negative correlation with talonavicular uncoverage index and talonavicular angle. Simple linear regression was used to assess the relationship between radiographic and foot pressure component measurements. For every unit change in talonavicular uncoverage index, the predicted value of medial midfoot pressure was [9.9 + 27 (talonavicular uncoverage index)]. This equation accounted for 17.9% of the changes in the medial midfoot pressure. Tibial foot angle and maximum knee extension also contributed to the heel impulse. The radiographic indices of the planovalgus foot can explain the changes in some foot pressure components.

► MMF and heel impulse correlate with radiographic indices in CP planovalgus deformity. ► Foot radiograph may explain part of pedobarograph changes in CP planovalgus deformity. ► Talar head coverage radiographic indices can predict the severity of planovalgus in CP.