Assessment of hindfoot deformity by three-dimensional MRI in infant club foot

In 12 infants aged under 16 months with unilateral club foot we used MRI in association with multiplanar reconstruction to calculate the volume and pr incipal axes of inertia of the bone and cartilaginous structures of the hin dfoot. The volume of these structures in the club foot is about 20% smaller than t hat in the normal foot, The reduction in volume of the ossification centre of the talus (40%) is greater than that of the calcaneus (20%). The long ax es of both the ossification centre and the cartilaginous anlage of the calc aneus are identical in normal and club feet. The long axis of the osseous n ucleus of the talus of normal and club feet is medially rotated relative to the cartilaginous anlage, but the angle is greater in club feet (10 degree s v 14 degrees). The cartilaginous structure of the calcaneus is significan tly medially rotated in club feet (15 degrees) relative to the bimalleolar axis. The cartilaginous anlage of the talus is medially rotated in both nor mal and club feet, but with a smaller angle for club feet (28 degrees v 38 degrees). This objective technique of measurement of the deformity may be o f value preoperatively,