Evaluation of calcaneal malposition by magnetic resonance imaging in the infantile clubfoot.

Magnetic resonance imaging (MRI) can clearly visualize both the ossification centers and surrounding cartilage of growing bones and enable a three-dimensional analysis of their positional relationships by using overlapping images. The calcaneal position was evaluated based on five newly proposed parameters of magnetic resonance images in 30 clubfeet of 18 infants with the bimalleolar and lower leg axes as reference lines. Sixteen unaffected feet in the unilateral cases were analyzed as normal feet. MRI showed that the calcaneus in clubfoot rotated internally, medially and posteriorly with reference to the bimallelar axis and that it took an equinus and a varus position with reference to the lower leg axis as compared with the normal foot. These five parameters and their normal values on the calcaneal position should be useful for the evaluation of infantile clubfeet.