Combined pelvic ring disruption and acetabular fracture: associated injury patterns in 40 patients.

OBJECTIVES: Combined pelvic ring disruptions and acetabular fractures are thought to be uncommon. Our objectives were to characterize concomitant injury patterns and to compare them with historically observed rates for each injury in isolation.

DESIGN: Retrospective review comparing a study group with historical controls. Fracture patterns were compared with our institution's isolated injury patterns and with isolated injury patterns of other published series.

SETTING: Level I academic medical center.

PATIENTS: Between 1997 and 2001, 854 pelvic ring disruptions and 457 acetabular fractures were evaluated. Forty patients sustained combined injuries.

INTERVENTION: None.

MAIN OUTCOME MEASUREMENTS: Fracture patterns, Injury Severity Scores, and mortality rates.

RESULTS: Our series of combined injuries included 5% posterior wall fractures. This was significantly different from the 30% incidence of posterior wall fractures among isolated acetabular fractures at our institution (P < 0.006). No posterior column or posterior column with associated posterior wall fractures occurred. Fifty-three percent of the patients sustained anterior-posterior compression pelvic ring injuries, exceeding our center's 19% norm for isolated pelvic ring injuries (P < 0.001). For combined injuries, the mean injury severity score was 27.9 and the overall mortality rate was 13%. Early death occurred in 19% of patients with combined anterior-posterior compression injuries and 6% with lateral compression injuries.

CONCLUSIONS: Patients with combined pelvic and acetabular injuries have multiple system injuries and high Injury Severity Scores. Fracture patterns differ from those observed with isolated injuries. Posterior acetabular fractures are uncommon components. Anterior-posterior compression pelvic injuries seem much more frequent in cases of combined injuries than isolated injuries and are associated with high mortality rates.

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