Onset of ossification of the tarsal bones in congenital clubfoot.

Subjects of this study were 45 patients with 56 idiopathic congenital clubfeet (34 boys with 42 feet and 11 girls with 14 feet) who underwent successful conservative treatment. Radiologic examinations were performed at intervals of 3 months. In anteroposterior radiographs of bilateral feet, the period of appearance of the ossification center was observed for the first, second, and third cuneiform and the tarsal navicular. The ossification of the tarsal bones in the congenital clubfeet occurred later than that in the unaffected feet in boys. The difference between the clubfeet and the unaffected feet was particularly statistically significant for the tarsal navicular and the second cuneiform (p < 0.01). The tarsal naviculars, the first cuneiforms, and the second cuneiforms in clubfeet and in unaffected feet started to be ossified significantly earlier in girls than in boys. Ossification occurred out of order in three of 56 clubfeet and three of 34 unaffected feet.