Age-dependent dynamic sonographic measurement of pediatric clubfoot.

BACKGROUND: US shows promise in evaluating clubfeet. In order to assess responses to therapy, the measurements of normal feet and clubfeet must be known.

OBJECTIVE: To investigate the role of US measurement in quantitatively evaluating normal feet and clubfeet in children, and to assess changes in these feet with age.

MATERIALS AND METHODS: Patients <1 year old with unilateral or bilateral clubfoot deformity underwent US examination of the foot with specific attention to the medial malleolar to navicular (MMN) distance. Measurements were made in neutral and full adduction positions, and in the abduction position simulating the Ponseti maneuver. Children undergoing US for other reasons had the same imaging performed and served as controls.

RESULTS: A total of 127 feet in 66 children were evaluated (20 children had bilateral clubfeet, 25 had unilateral clubfoot, and 21 had normal feet). Clubfeet had significantly (P < 0.001) lower MMN measurements at all three positions than control feet. These distances increased with patient age for both normal feet and clubfeet, but the rate of increase was less for clubfeet.

CONCLUSION: Normal feet and clubfeet exhibit marked differences in MMN distances, as well as differences in rate of change over time. By understanding the age-dependent variability of normal feet and clubfeet, dynamic sonography can help assess clubfoot anatomy and could help to assess the effect of treatment interventions.