CAN WE PREDICT THE NEED FOR PELVIC SURGERY IN THE TREATMENT OF DDH?

Abstract

DDH incidence falls from 5–20 per 1000 at birth to 1–2 per 1000 by 3 weeks. Some patients present late and frequently require surgical intervention. If the hip cannot be contained without tension, these children undergo open reduction +/− a femoral shortening, varus and derotation osteotomy. Salter’s osteotomy, may be performed either at index surgery or later in the presence of persisting acetabular dysplasia. Our aim was to see if we could predict which cases of persistent DDH would require both femoral and pelvic surgery to contain the affected hip, using a single plain AP radiograph of the pelvis in the outpatient setting.

We performed a retrospective study of all children older than 18 months with persistent DDH of one or both hips, over the last 5 years, who had undergone femoral and/or pelvic surgery to contain the hip. Plain AP pelvic radiographs were standardised according to the method described by Tonnis. From these radiographs the acetabular indices and child’s age in months, were recorded. Syndromic and children with non-standard x-rays were excluded.

Thirty nine hips (34 female, 5 male), age range of 18–102 months, formed our study group. 53% of hips having femoral surgery later required pelvic surgery for persisting acetabular dysplasia. Examining the data in these cases, the difference between the acetabular index of the normal and affected hip was always greater than 20 degrees and the child’s age in months.

Using this method we conclude that it is possible to predict which cases of persistent DDH will require pelvic surgery to fully contain the affected hip and that this can be done with one AP pelvic radiograph in the outpatient clinic. The benefit is avoidance of unnecessary pelvic osteotomies, and being able to determine the cases which should have a pelvic osteotomy at index procedure.