The Lateral Stress Radiograph Identifies Occult Instability of Lateral Compression Pelvic Ring Injuries Without Sedation

Abstract

Objectives: 

To determine if pelvic ring displacement on the lateral stress radiograph (LSR) correlated with displacement on examination 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 taken in the lateral decubitus position (LSR) was performed on awake patients before 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 nonoperatively.

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. See Instructions for Authors for a complete description of levels of evidence.