Comprehensive assessment of acetabular morphology in developmental dysplasia of the hip: introducing novel parameters for pediatric evaluation

Developmental dysplasia of the hip (DDH) represents a wide range of abnormalities affecting the acetabulum and femoral head. Traditional diagnostic tools such as anteroposterior pelvic radiographs are limited in evaluating the three-dimensional morphology of the acetabulum, especially in pediatric populations. This study introduces novel measurement parameters that include both angular and dimensional metrics for a comprehensive assessment of acetabular morphology. It also compares these parameters between normal and dysplastic hips in pediatric population. Computed tomography scans of 35 children with unilateral DDH, aged between four and 48 months, were analyzed, comparing dysplastic and normal hips. Parameters measured included anterior and posterior acetabular indexes and lengths, anterior and posterior coverage angles, lengths, and posterior coverage area, dome length and dome coverage. Statistical analyses evaluated differences between groups. Dysplastic hips exhibited higher anterior and posterior acetabular index values and reduced anterior and posterior acetabular lengths, reflecting global elongation and shallowness. Anterior coverage angle was significantly greater, while posterior coverage angle and posterior coverage parameters were reduced, highlighting posterior wall deficiencies. Dome coverage was also significantly decreased. All measurements showed good to excellent interobserver and intraobserver reliability (0.68-0.94 and 0.76-0.92, respectively). Our findings suggest that DDH involves global acetabular deficiencies, including posterior insufficiency, challenging the traditional focus on anterolateral deficiencies. The introduced parameters provide a reproducible method for evaluating pediatric acetabular morphology, offering valuable insights for diagnosis and treatment planning. Future studies should validate these findings and explore MRI for enhanced diagnostic accuracy.