Development of congenital clubfoot during growth: a long-term study on the basis of pedobarography, biomechanics, and magnetic resonance imaging measurements of muscle volumes.

The aim of this study was to clarify the degree to which the operated congenital asymptomatic clubfoot still shows malpositions or whether it approaches a physiological development with increasing age. Clubfeet of 12 children were examined repeatedly over up to 10 years using pedobarography. The muscle volumes of the lower legs were investigated with MRI and compared with those of a healthy control group. Although some characteristics of clubfoot remained in the plantar pressure distribution, a gradual decrease in the heel and metatarsus load accompanied by an increase in the forefoot load could be registered as is typical for a developing healthy child's foot. The MRI showed a reduced volume of all muscles of the affected lower leg. A correlation was detected between the measured moments in the upper and lower ankle joints and the volumes of the muscles that move these joints. Even though a functional and anatomical separation between the two groups existed, the general developmental changes during growth were similar. The combination of pedobarographic data and derived joint moments with MRI-measured muscle volumes indicated that higher ankle joint moments in clubfoot were associated with smaller muscle volume and were therefore generated by higher joint rigidity.