Clubfoot in children is a common deformity that causes the foot to be twisted in and turned down. Sometimes it affects both feet, but in many children it is unilateral (just on one side). Studies of unilateral clubfoot often use the unaffected side as normal for comparison. But is it really normal?
In this study, researchers compare weight-bearing forces through the
unaffected foot of children with unilateral clubfoot to normal feet of
children who don’t have this condition.
The children in both groups were between four and eight years old. A small
group of 16 children with unilateral clubfoot and 110 normal children were
included. Thirteen of the children with clubfoot had surgery by the same surgeon by age one year.
The children in both groups were asked to walk along a surface that could measure forces through the foot with each step. Peak pressure was measured for each of 10 points on the foot from the heel to all five toes.
Analysis of the results showed a major difference between the two groups.
Children with unilateral clubfoot had less ground reaction force on both sides
compared to the normal group.
For example, when the foot was flat or during toe-off while walking, forces in
the midfoot were much less in the unaffected side of the clubfoot group
compared to the normal group. In general, the peak pressures in the unaffected foot of the clubfoot group were lower than in the feet of normal children.
These results suggest a previously undetected change in the motor pattern of the clubfoot group. The nervous system may be trying to adapt and make the gait pattern equal and even from side to side.
This is the first study to show that pressure distribution on the bottom of
the unaffected foot is not the same for children with unilateral clubfoot as
it is for children without clubfoot. Although it means recruiting more people
for studies, the authors advise against using the unaffected foot as a control
or comparison in studies of clubfeet.