Cortical Impaction in Posterior Wall Acetabular Fractures.

OBJECTIVES: To report the incidence of patients with extra-articular posterosuperior acetabular cortical impaction associated with a posterior wall acetabular fracture-dislocation.

DESIGN: Retrospective case series.

SETTING: Regional Level 1 trauma center.

PATIENTS/PARTICIPANTS: Ninety-seven patients who sustained an isolated posterior wall acetabular fracture-dislocation from July 2007 until July 2017.

INTERVENTION: The medical record and the computed tomography (CT) scan of the abdomen and pelvis were reviewed including axial, coronal, and sagittal reconstruction images and 3D surface renderings.

MAIN OUTCOME MEASUREMENTS: Each pelvic CT scan was evaluated for impaction of the extra-articular posterosuperior acetabular cortical surface associated with posterior wall acetabular fracture-dislocations. The reduction accuracy was assessed for each patient with cortical impaction using postoperative CT scans. The final attending radiology report was reviewed to see whether the cortical impaction was noted.

RESULTS: Four of the 99 patients (4.12%) had identifiable areas of cortical impaction on preoperative CT imaging. Reduction accuracy demonstrated 1 anatomical reduction, 2 imperfect reductions, and 1 poor reduction. The final attending radiologist report did not comment on any patient with cortical impaction.

CONCLUSIONS: Our study demonstrates that a small number of patients sustain cortical impaction of the posterosuperior acetabular cortical surface along with their posterior wall acetabular fracture-dislocation. Although uncommon, preoperative imaging should be scrutinized to identify this clinical entity. As part of the preoperative plan, the surgeon can anticipate the cortex available for reduction verification and whether any additional steps or altered surgical approaches are needed to achieve an anatomical reduction.

LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.