Measurement of Acetabular Anteversion in Developmental Dysplasia of the Hip in Children by Two- and Three-dimensional Computed Tomography

Abstract

This study assessed the angle of acetabular anteversion (AA) in 66 children with developmental dysplasia of the hip (132 hips: 24 left, 25 right, 17 bilateral and 49 unaffected hips as controls). The AA was measured by two- and three-dimensional computed tomography (2D-CT and 3D-CT). Measurements were taken by three observers and repeated 2 weeks later by one of these observers. Intra- and inter-observer agreement was analysed using the intra-class correlation coefficient. For all hips, the mean AA (±SD) measured by 2D-CT versus 3D-CT was statistically significantly different (15.76 ± 5.23° versus 16.76 ± 4.43°, respectively). The mean (±SD) AA by 3D-CT in unaffected and affected hips was also statistically significantly different (13.92 ± 3.95° versus 18.44 ± 3.82°, respectively). A significant positive correlation between age at presentation and AA was found in affected, but not unaffected, hips. The 3D-CT showed better intra- and inter-observer agreement than 2D-CT for assessing AA hence is a more reliable measurement of AA. An increased AA is one component of anatomical abnormalities in developmental dysplasia of the hip and the abnormality appears to worsen with age.