No association between residual forefoot adduction and the position of the navicular in clubfeet treated by posterior release.

Medial displacement of the navicular has been considered a major explanation for residual forefoot adduction (FFA) in congenital clubfoot and also a frequent reason for dissatisfaction after limited surgery. In this study, it was hypothesized that there would be an association between the degree of medial displacement of the navicular and residual FFA in clubfeet. The position of the navicular was retrospectively measured by ultrasonography in 49 clubfeet in 35 children at ages 3 to 6 years and correlated to residual FFA measured on footprints and radiographs (talo-first metatarsal angle). In the 49 clubfeet, the navicular was significantly more medially displaced toward the medial malleolus than in the 21 contralateral normal feet (P < 0.001). However, there was no correlation between the degree of medial displacement of the navicular and the degree of FFA measured on footprints (P = 0.690) or on radiographs (P = 0.390). Thus, there were clubfeet with straight forefoot and a medially displaced navicular, that is, "spurious correction," and clubfeet with FFA and the navicular in correct position in relation to the head of the talus. Both patient satisfaction and foot score declined with larger FFA. The results support the view that ultrasonography is a helpful tool for assessing the position of the navicular. The critical issue for analysis is whether the FFA is due to malalignment in the talonavicular joint or more distally.