Histochemistry of the triceps surae muscle in idiopathic congenital clubfoot.

The histochemical composition of the triceps surae muscle was investigated in 13 previously unoperated children (age 9-24 months) with unilateral idiopathic clubfoot. On both the normal and the affected side, the percentage of type I fibers was significantly higher than that of the other fiber types. The muscle biopsies from the clubfoot side showed an increase in their connective tissue content. The affected side showed a nonsignificant higher percentage of type I fibers, whereas the average capillary density and capillary to fiber ratio were significantly lower.