Ground reaction force patterns in children with idiopathic unilateral clubfeet

Clubfoot is a common birth defect affecting 2-3 children per 100 live births. The child is born with a foot in equinus, forefoot adduction, and heel varus. The defect primarily lies within the subtalar joint, the articulation between the talus and calcaneus. Assessment of the clubfoot, to date, depends upon clinical measurement, radiographic measurements, and observations of the child's gait. The clinical measurements are subjective in nature. While the radiographic measures are more objective, they have shown to be poorly correlated with the clinical outcome. The problem in assessing clubfeet is the lack of a dynamic objective assessment which correlates well with the clinical assessment. The purpose of this study is examine the differences between ground reaction force patterns in children with normal feet versus children with clubfeet, and more specifically determine whether there is a significant correlation between subtalar motion and vertical moment. Three groups of feet were used for the study: the first group included one foot from children with normal feet (n=16), the second group included the affected clubfoot of children with unilateral clubfoot (n=7), and the third group included the intact foot of the children with clubfoot (n=7). The children's feet were clinically examined by an orthopaedic resident, measuring ankle and subtalar range of motion, and heel position on stance. Ground reaction force data was collected with 3 trials for each group for each subject. One way ANOVA's showed significant differences between the clubfoot group and the intact foot group and the normal foot group for all clinical parameters. Regression analysis showed that the net vertical moment correlated highly (r=.84) with the subtalar range of motion and heel position in the clubfoot and intact groups, however, not the normal group. For example, a more rigid, varus foot produced a greater internal net torque. The net anterior-posterior impulse correlated highly (r=.92) with ankle range of motion. Thus, an ankle with a greater range of motion produced a greater propulsive force. The rigid and varus nature of the clubfoot does reduce the foot's ability to efficiently absorb and transmit the torque produced by the leg. The restricted ankle range of motion in the clubfoot also affects the ability for the foot to produce a normal powerful propulsive force during gait. This limited propulsion may be cause by the current standard of treatment of the clubfoot. A surgeon could perform an anterior wedge osteotomy of the tibia instead of an achilles lengthening to obtain adequate dorsiflexion and maintain a strong plantarflexor muscle. Before any of these conclusions can be made with confidence, a study with more subjects needs to be undertaken.Education, Faculty ofCurriculum and Pedagogy (EDCP), Department ofGraduat