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A prospective randomized trial evaluating immediate treatment compared with active sonographic surveillance for infants with dysplastic, nondislocatable hips demonstrated that surveillance halved the need for treatment without having an effect on the radiographic appearance of the hip at the age of one year1. In a study in which twenty-nine patients with bilateral dislocation of the hip were compared with thirty-eight patients with unilateral dislocation, there was no significant difference between the two groups with regard to the failure of Pavlik treatment2. Two studies analyzed factors associated with unsuccessful Pavlik harness treatment of dislocated hips3,4. In one series of 221 hips, successful reduction was obtained in 81.9% of the hips, with development of osteonecrosis in 8.8%3. Adduction contracture and decreased distance from the proximal medial femoral metaphysis (indicated by the “a” line) were identified as risk factors that were predictive of failure. Another study of eighty-five patients demonstrated a rate of Pavlik harness failure of 37%4. Sonographic findings associated with unsuccessful Pavlik harness treatment included an increased beta angle, superior femoral head migration relative to the labrum, and total femoral head displacement less than −30°4. In a retrospective review of late-presenting patients (age range, six to twenty-four months) who were managed with Pavlik harness reduction, 60% of Graf type-3 hips were reduced with no associated osteonecrosis, whereas no Graf type-4 hips were reduced5.A single-institution review of operative reduction of dislocated hips in late-presenting children demonstrated that femoral shortening osteotomy was more common in children with an age of more than thirty-six months or with femoral displacement of >30% of the pelvic height, with an overall prevalence of 35%6. In the study by Spence et al., open reduction combined with varus derotational proximal femoral osteotomy (thirty-eight patients) was compared with open reduction combined with Salter innominate osteotomy (thirty-three patients) with regard to the effect on developing acetabular morphology7. The authors reported significantly better acetabular improvement in the Salter osteotomy group at the time of the four-year follow-up. Kitoh et al., in a study of eighty-six who were patients managed with Salter osteotomy for the treatment of acetabular dysplasia, evaluated geometric acetabular changes and reported an average improvement of 19° in the center-edge angle and of 13° in the acetabular index8. That study provided valuable guidelines for surgeons performing the Salter osteotomy as acetabular morphologic improvement correlated with intended alterations in lateral rotation, displacement, and reduction in obturator foramen height. Osteonecrosis of the femoral epiphysis remains a serious complication in the treatment of developmental dysplasia of the hip, although it can be difficult to detect on early post-reduction radiographs. A review of forty-seven patients who underwent closed reduction suggested that a femoral epiphyseal height:width ratio of <0.357 as measured on radiographs made twelve to eighteen months after reduction suggests the development of a nonspherical femoral head as a consequence of osteonecrosis9.In the study by Sankar et al., the average femoral anteversion in thirty children (average age, thirty-three months) who presented for open reduction for the treatment of developmental dysplasia of the hip was 50° (range, 0° to 95°)10. Kobayashi et al., in an effort to determine when patients begin to show radiographic signs of dysplasia, analyzed acetabular development on radiographs of the contralateral hip for eighty-eight patients who were followed for unilateral acetabular dysplasia11. The authors concluded that morphologic differences between normal and dysplastic acetabula are evident after the age of six years that and there are significant changes from the age of six to twelve years. No hip with a center-edge angle of <15° developed a normal acetabulum.