Discrepancies in ultrasonography of the infant hip.

A total of 4,984 ultrasonographic (US) examinations of infant hips were done for the diagnosis or management of congenital/developmental dislocation/ dysplasia of the hip; 48 instances of lack of correlation (0.96%) between the US and radiographic images were noted. Analysis of these cases permitted classification into two groups: (a) apparent discrepancy (44 cases, 0.88%) for which faulty technique or interpretation of the sonogram/radiograph, hyperlaxity, inadvertent stress views, and lateral ossification defects led to disparity in the imaging modalities; and (b) true discrepancy (4 cases, 0.08%) where no explanation was possible for the dissimilarity. The relevance of this study is that the majority of discrepancies can be eliminated by (a) avoiding the common causes of apparent discrepancies mentioned in this article and by (b) the use of the Graf and Harcke techniques as complementary methods of US examination.