Radiographic Determinants of Early Failure After Posterior Wall Acetabular Fracture Fixation.

A retrospective review was conducted at an academic trauma center to determine whether fracture characteristics or aspects of native anatomy are predictive of early failure after fixation of posterior wall acetabular fractures. A chart review of posterior wall acetabular fractures treated from 2004 to 2009 yielded the study group that met the inclusion criteria. The study group included 18 consecutive patients who had clinical failure. The control group included 27 patients who did not have clinical failure. Operative notes were reviewed and axial view computed tomography scans were analyzed to determine 8 fracture descriptors (dislocation, comminution, marginal impaction, femoral head injury, incarcerated fragments, involvement of the subchondral arc, proximal-to-distal fracture extension, and size of the fracture measured by 3 methods) and 6 native anatomy descriptors (transverse plane acetabular anteversion, anterior acetabular sector angle, 2 measures of the posterior acetabular sector angle, and 2 measures of change in the posterior acetabular sector angle). Failure of treatment (n=18) was defined as the need for total hip arthroplasty (n=5) or the development of symptomatic posttraumatic arthritis (n=13). Fisher's exact test and Student's t test were conducted. The only variable that was predictive of failure of operative treatment of posterior wall fractures was extension of the fracture into the subchondral arc (12 of 18 patients in the failure group vs 7 of 27 patients in the nonfailure group, P=.01). Native anatomy, fracture size, and marginal impaction did not play a significant role in predicting failure. [Orthopedics. 2016; 39(6):e1104-e1111.].