Surgery for Unilateral Sacral Fractures: Are the Indications Clear?

OBJECTIVES To evaluate unilateral sacral fractures and compare those treated operatively versus nonoperatively to determine indications for surgery. DESIGN Prospective, multicenter, observational study. SETTING Sixteen trauma centers. PATIENTS/PARTICIPANTS Skeletally mature patients with pelvic ring injury and unilateral zone 1 or 2 sacral fractures and without anteroposterior compression injuries. MAIN OUTCOME MEASUREMENTS Injury plain anteroposterior, inlet, and outlet radiographs and computed tomography scans of the pelvis were evaluated for fracture displacement. RESULTS Three hundred thirty-three patients with unilateral sacral fractures and a mean age of 41 years with a mean Injury Severity Score of 15 were included. Ninety-two percent sustained lateral compression injuries, and 63% of all fractures were in zone 1. Thirty-three percent of patients were treated operatively, including all without lateral compression patterns. Operative patients were more likely to have zone 2 fractures (54%) and to have posterior cortical displacement (29% vs. 6.2%), both with P < 0.001. Over 60% of all patients had no posterior displacement. Mean rotational displacements comparing the injured side versus the intact side were no different for patients treated operatively compared with those treated nonoperatively. CONCLUSIONS Most unilateral sacral fractures are minimally or nondisplaced. Many patients with radiographically similar fractures were treated operatively and nonoperatively by different surgeons. This suggests an opportunity to develop consistent indications for treatment. LEVEL OF EVIDENCE Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.