Arthrography in the evaluation of congenital dislocation of the hip.

To assess the value of intraoperative arthrography, 48 preoperative hip arthrograms of 35 children under 18 months of age treated for congenital dysplasia of the hip were reviewed. The frequency of the common arthrographic observations was assessed and was compared with the findings observed from the plain roentgenograms, and with the pathoanatomy seen at the time of open reduction. Arthrography proved reliable in identifying the depth of reduction (medial dye column, 100%), the configuration of the osteocartilaginous structures (96%), and the presence of potentially obstructing soft tissue (limbus, 98%, and ligamentum teres, 78%). Arthrography was less reliable in discerning psoas contracture (36%), despite its presence at all open reductions. Arthrography proved reliable in outlining the inverted limbus that can obstruct closed reduction. Because ossification of the femoral head was frequently eccentric, the center edge (CE) angle of Wiberg was calculated from arthrography more accurately than from roentgenograms.