Measurement of acetabular anteversion in children with developmental dysplasia of the hip by two-and three-dimensional computed tomography

Abstract

Objective To compare the difference of the measurement of acetabular anteversion (AA) between two-dimensional computed tomography (2D-CT) and three-dimensional computed tomography (3D-CT) in children with developmental dysplasia of the hip (DDH). Methods AA was measured by 2D-CT and 3D-CT in 66 children (132 hips) with DDH. Among them, 53 were females and 13 males. The mean age was 35.4 months, ranged from 4 to 132 months. The unilateral hip was affected in 49 eases, including left hips in 24 cases and right in 25 eases. Seventeen cases were bilaterally affected. The control group included 49 unaffected hips of the unilateral affected patients. Results For total 132 hips, the mean measurement of AA by 2D-CT was 16.69±4.55°, and 15.91±5.24° by 3D-CT, respectively (P<0.05). There was significant correlation between the two groups (γ=0.720, P.<0.001 ). In the unilateral affected patients, the average AA measured by 3D-CT was 11.43±3.82° in. unaffected hips and 18.55±4.04° in affected hips, and the difference was significant (P<0.001., In the affected hips, a significant positive correlation was found between the age and AA(γ=0.579, P<0.001). Conclusions The increased AA is the feature of anatomic deformity in DDH. AA should be evaluated by 3D-CT because 3D-CT is more reliable than 2D-CT in the measurement of AA. Key words: Hip dislocation; Acetabulum