THE TEARDROP IN CONGENITAL DISLOCATION OF THE HIP DIAGNOSED LATE - A QUANTITATIVE STUDY

We retrospectively reviewed the radiographs of the pelvis and hips of forty-five patients who had unilateral congenital dislocation of the h ip treated with closed reduction and application of a cast without sub sequent operations. The radiographs were made at the time of the initi al diagnosis, two years after the reduction, when the child was ten Se ars old, and at skeletal maturity. The width, shape, and type of the t eardrop; the thickness of the acetabular floor; the acetabular index; the center-edge angle; the articulotrochanteric distance; and the Seve rin class at maturity were measured in the dislocated and contralatera l, normal hips. At the time of the initial diagnosis, a well defined t eardrop was seen in thirty-six (80 per cent) of the normal hips and in seven (16 per cent) of the dislocated hips. There was no difference i n the width of the teardrop in the seven dislocated hips compared with that in the normal hips, although the v-shaped and crossed types of t eardrops were more frequent in the dislocated hips. The v shape was no t observed in the normal hips but was seen in sixteen dislocated hips two Sears after the reduction and in twelve dislocated hips when the c hildren were ten years old, The superior and inferior widths of the te ardrop of the dislocated hips were significantly greater than those of the normal hips (p < 0.001 and p < 0.05, respectively) when the child ren were ten years old. The hips with residual acetabular dysplasia ha d a v-shaped teardrop, widening of the superior width of the teardrop, and thickening of the acetabular floor. These hips, which were usuall y Severin class IV at the time of skeletal maturity had a poor prognos is in adult life.