LAUSR

OBJECTIVES To determine if pelvic ring displacement on the Lateral Stress Radiograph (LSR) correlated with displacement on exam under anesthesia (EUA). DESIGN Retrospective cohort study. SETTING Urban level I trauma center. PATIENTS/PARTICIPANTS Twenty consecutive patients with unilateral minimally displaced LC1 injuries with complete sacral fractures. INTERVENTION An anteroposterior pelvis radiograph performed in the lateral decubitus position (LSR) was performed on awake patients prior to EUA in the operating room. MAIN OUTCOME MEASUREMENTS Correlation between ≥1 cm of pelvic ring displacement on the LSR and EUA. RESULTS The LSR demonstrated ≥1 cm of displacement in 11 of the 20 patients (55%). All of these patients had ≥1 cm of displacement on EUA and underwent surgical fixation. The remaining 9 patients with <1 cm of displacement on the LSR also had <1 cm of displacement on EUA and were managed non-operatively. CONCLUSIONS The LSR reliably identified occult instability in LC1 pelvic ring injuries and demonstrated 100% correlation with EUA. In contrast to EUA, the LSR does not require sedation and normalizes the amount of force applied to determine instability. LEVEL OF EVIDENCE Diagnostic level II.