Standard radiographs and computed tomographic scan underestimating pediatric acetabular fracture after traumatic hip dislocation: report of 2 cases.

Posterior wall acetabular fractures are rare in the pediatric patient but require proper management to prevent significant complications. Plain radiographs and computed tomography scans are standard diagnostic imaging used with clinical examination of hip stability to determine if the injury requires open reduction and internal fixation. Two cases are presented of adolescent traumatic hip dislocations and posterior wall fractures in which radiography underestimated the extent of the posterior wall fracture. In one case, a magnetic resonance imaging study more clearly characterized the injury. Because the ossification of the posterior wall occurs throughout adolescence, magnetic resonance imaging may be a useful tool in characterizing these fractures and assisting with surgical planning.