Ultrasound evaluation of clubfoot correction during Ponseti treatment: a preliminary report.

BACKGROUND The Ponseti method of manipulation is widely used in the treatment of clubfoot. Monitoring of correction is usually based on clinical judgment, and there is a need for an objective method of evaluation. The small bones of the newborn foot are essentially cartilaginous and can be visualized well on sonography as against radiographs. METHODS A prospective study was conducted on 32 clubfeet (26 subjects; age range, 12 days to 3 months) using ultrasound. Sonography was performed using the coronal medial projection at the start of treatment, when midfoot Pirani score was zero (foot fully abducted), and at the end of treatment. The medial malleolus to navicular distance and the talo-cuneiform angle were measured with foot position at rest and during the simulated Ponseti maneuver. The normal feet in unilateral cases served as controls. RESULTS With the Ponseti method of manipulation, there was a significant increase in the medial malleolus to navicular distance and improvement in the talo-cuneiform angle at the end of treatment, when compared with the pretreatment values (P < 0.001). All feet were clinically well corrected. However, 5 feet (15%) showed a "spurious correction," which was only detected on ultrasound. This was identified by the fact that the navicular was not fully reduced over the head of the talus, and there was a break in the naviculo-cuneiform joint. It was difficult to predict which feet were likely to develop a spurious correction, although the 5 feet in our study were stiffer, more severely deformed, and showed less correction on initial manipulation as compared with the feet that corrected well. CONCLUSIONS Clubfoot correction during serial manipulation can be monitored using sonography. An accurate realignment of the talo-navicular joint can be demonstrated, and presence of spurious correction can be detected early.