Background
The spectrum of abnormalities in developmental dysplasia of the hips (DDH) is not limited to osseous changes, but extends to include periarticular soft tissue changes, which could not be visualized by conventional radiographs or computed tomography (CT). Both MRI and conventional arthrogram can evaluate those soft tissue obstacles to reduction.
Patients and methods
In total, 16 children with DDH (21 hips), dated for surgical management by open reduction, were chosen. All patients were examined by preoperative MRI as well as intraoperative arthrogram. Both modalities were used to assess different obstacles to reduction, such as the labrum, pulvinar, ligamentum teres (LT), iliopsoas tendon interposition, and the transverse acetabular ligament (TAL).
Results
Both MRI and conventional arthrogram showed similar sensitivity (100%) for detection of ligamentum teres pathology, labral inversion, and hypertrophied pulvinar. MRI showed higher sensitivity than arthrogram for detection of the iliopsoas tendon interposition (100% vs. 64.5%) and for detection of the thickened transverse acetabular ligament (85.7% vs. 19%).
Conclusions
Both MRI and conventional arthrogram can visualize the soft tissue obstacles to reduction in dysplastic hips. MRI is a noninvasive technique, requiring sedation in the pediatric population. Conventional arthrogram is an invasive technique. However, significant complications can be readily avoided.