Background: Limited data exist in the literature with regard to the amount of femoral anteversion in children with developmental dysplasia of the hip (DDH). The data that do exist are variable: certain studies cite increased version in DDH compared with normal while others have found no significant difference. The purpose of our study was to quantify the degree of femoral anteversion in a large, consecutive series of children with DDH.
Methods: We performed a prospective study on 37 consecutive hips (30 patients) that were undergoing surgical procedures for DDH. After induction with general anesthesia (before the planned procedure), arthrograms were performed to allow accurate localization of the center of the femoral head. An anteroposterior radiograph was taken with the patient positioned supine and the knee flexed 90 degrees over the end of the operating table and the leg held perpendicular to the plane of the table. The limb was then rotated 90 degrees for the lateral radiograph. The offset of the center of the femoral head to the midline of the femoral shaft was measured in each view and a simple trigonometric relationship was used to calculate the femoral version.
Results: The mean age of the children in our series was 33.5 months (range: 6 to 79 mo). There were 4 boys and 26 girls; 7 patients had bilateral involvement. The mean femoral anteversion was 50.3 degrees+/-17.9 degrees. Significant variability was found: the lowest femoral version measured 0 degrees and the highest measured 95.7 degrees.
Conclusions: In most of our children with DDH, femoral anteversion was increased compared with published norms; however, significant variation existed. Given the variability of femoral anteversion, we believe that an individualized surgical approach is warranted, including preoperative assessment of the femoral version followed by derotational femoral osteotomy only if indicated by the patient's specific torsional profile.
Level of evidence: Anatomic study.