Focused dynamic sonographic examination of the congenital clubfoot

Background US readily demonstrates cartilaginous structures, and static sonography has shown potential in evaluating clubfoot deformity. Objective To investigate the potential of dynamic sonography in the evaluation of the congenital clubfoot. Materials and methods Sonography was used for static and dynamic stress evaluation of 13 clubfeet and 35 normal feet in 24 patients (ages 0-32 weeks). Dynamic foot sonography was performed using a single-operator bimanual scanning technique. The examination involved coronal oblique evaluation of the medial malleolar-navicular (MMN) distance and the calcaneocuboid relationship, sagittal evaluation of the talonavicular relationship, and transverse evaluation of navicular subluxation, rotation, and deformation. Dynamic abduction/adduction stress maneuvers were performed, measured by the MMN. Results The clubfoot "gristle" is a consistent, measurable soft-tissue landmark in clubfeet, connecting the medial malleolus to the medial navicular and talus. Mean MMN distances in clubfeet in the neutral position and abduction were significantly different from these distances in the normal paired foot (differences of 8.7 mm neutral position and 7.94 mm abduction), as compared to bilateral normal feet (differences of 0.98 mm neutral position and 1.43 mm abduction). Navicular subluxation showed good correlation between highly deformed and subluxated navicular bones and a tight medial clubfoot complex. Conclusions Focused dynamic foot sonography is useful in providing a specific and detailed functional preoperative and/or postoperative assessment of the congenital clubfoot.