Pathoanatomy of the anterior column-posterior hemitransverse acetabular fracture

Purpose: To define the pathoanatomy of the anterior column-posterior hemitransverse (ACPHT) subtype of acetabulum fractures and assess the morphologic variation therein.

Methods: Retrospective cohort study including 50 patients age greater than 60 with an ACPHT acetabular fracture managed operatively over an 11-year period at an ACS Level 1 Trauma center. Cross-sectional CT images were reviewed for anterior column/wall comminution, anterior column fracture exit point, completeness of the anterior column and posterior column fractures, articular impaction and quadrilateral surface continuity with the posterior column.

Results: Comminution of the anterior column/wall was seen in 60% of patients. The anterior column fracture line exit was variable and exited below the anterior inferior iliac spine (AIIS) in 36% of fractures, at the AIIS or between the iliac spines in 40%, and through the iliac crest in 24%. A complete fracture was present in 72% of anterior column fractures and 44% of posterior column fractures. Impaction of the acetabular joint surface was present in 84% of patients. Continuity of the quadrilateral surface with the posterior column was present in 60% of cases.

Conclusions: Significant variability exists within the ACPHT fracture pattern. Understanding the variability within the ACPHT subtype is critical for adequately analyzing these patterns and has implications in future biomechanical studies and implant design.

Level of evidence: Level IV.