Correlation between arthrograms and operative findings in congenital dislocation of the hip.

Forty-two patients with congenital dislocation of the hip demonstrated good correlation between the arthrograms and the operative findings of a large ligamentum teres, an hourglass constriction of the capsule, a prominent transverse ligament and an acetabular bulge. The number of hips found at operation to have an inturned labrum was smaller than had been predicted on arthrogram. Larger percentages of hips with inturned labrum found at operation have been reported by other authors. We noted an acetabular bulge in a sizeable number of our patients. On arthrogram an inturned labrum has to be differentiated from the acetabular bulge and from an hourglass constriction. Open reduction is indicated when arthrogram indicates an interposition of a large ligamentum teres, an hourglass constriction, or a prominent transverse ligament. Isolated findings of an acetabular bulge or an inturned labrum on arthrogram are not indications for open reduction.