The cranial unstable transverse acetabulum fracture: an important variant.

Purpose: Achieving anatomic reduction in combined injuries of the pelvic ring and acetabulum is critical to optimizing outcome. One of the most common combined patterns is a transverse-type acetabular fracture with associated ipsilateral sacroiliac joint instability. The optimal order of fixation (pelvis-first versus acetabulum-first) in these patients remains unclear. The present study aimed to analyze the impact of operative sequence on outcomes when treating transverse variant acetabulum fractures with concomitant posterior pelvic ring disruption.

Methods: Across a 12-year period, 24 patients with transverse variant (e.g., transverse, transverse posterior wall, or T-type) acetabulum fractures with unstable cranial segments were identified. This cohort included 17 patients treated with a pelvis-first approach and 7 patients treated with an acetabulum-first approach. Data regarding demographics, mechanism, associated injuries, operative details, post-operative reduction quality, and clinical outcomes were collected.

Results: The average age in this series was 37 years, and 63% of patients were male. All injuries involved a high-energy mechanism, most commonly motor vehicle collision (63%). There were no significant differences in demographic or injury characteristics between cohorts. A pelvis-first approach was associated with a significantly lower rate of poor reduction quality (12% vs. 57%, P = 0.038) and lower blood loss on average (500 mL vs. 1000 mL, P = 0.009) when compared to an acetabulum-first approach.

Conclusion: In this series, a pelvis-first approach was associated with improved reduction quality and decreased blood loss among patients with operatively managed transverse acetabulum fractures with a cranial unstable fracture fragment.

Level of evidence: IV.