Preoperative roentgenographic evaluation for osteotomies about the hip in children

Innominate or femoral osteotomy sometimes is recommended for the surgical treatment of diseases of the hip in children, particularly congenital dysplasia and Legg-Perthes disease. The decision to perform an innominate osteotomy (Salter) or a varus derotation femoral osteotomy often hinges on no more than the preference of the surgeon. Some of this indecision is due to the lack of a definitive way to determine what these operations will accomplish in three dimensions and to the difficulty in predicting the exact amount of coverage of the femoral head that will be obtained by these procedures. A more accurate way to document the changes that can be anticipated after these procedures by roentgenographic evaluation would be helpful. If preoperative roentgenograms could show the relationships between the femur and acetabulum that could be anticipated after each of these procedures, the surgeon could make a more rational preoperative decision about the merits of each procedure. Roentgenograms of the hip made with the femur held in carefully measured amounts of internal rotation and abduction have been used for the preoperative evaluation of varus derotation osteotomy. A similar evaluation of the three-dimensional changes in acetabular orientation after a Salter innominate osteotomy should be possible if appropriate roentgenograms are made. Roentgenological techniques are described.