Comparing Emergency Department Stress of Lateral Compression Type 1 Pelvis Fractures with a Validated Instability Scoring System

Introduction:Lateral compression type 1 (LC1) pelvic ring injuries represent a heterogeneous group of fractures with controversial surgical indications. Recently, multiple institutions have suggested the safety and reliability of an emergency department (ED) stress to evaluate for occult instability. The purpose of this study was to correlate ED stress examination of LC1 pelvis fractures against a validated fracture instability scoring system.Methods:This was a retrospective review of a consecutive series of 70 patients presenting with minimally displaced LC1 fractures at a level 1 academic trauma center. All patients were stressed in the ED radiology suite, and displacement was measured by comparing calibrated stress radiographs with static radiographs (>10 mm displacement defined positivity). ED stress results were compared with radiographic scores assigned according to the validated Beckmann scoring system (score <7: stable - nonsurgical recommendation; score 7 to 9: indeterminant recommendation; and score >9: unstable - surgical recommendation).Results:Thirteen patients had a positive ED stress examination, and 57 patients stressed negative. The mean displacement was significantly different between the three groups (Beckmann 5 to 6: 3.31 mm, SD = 2.4; Beckmann 7 to 9: 4.23 mm, SD = 3.2; Beckmann 10+: 12.1 mm, SD = 8.6; P < 0.001). Zero of 18 patients in the stable group stressed positive, and only 3 of 38 patients in the indeterminant group stressed positive (7.9%). Finally, 10 of 14 patients in the unstable group stressed positive (71.4%; P < 0.001). Sacral displacement (P = 0.001), superior ramus location (P < 0.02), and sacral columns (P < 0.001) significantly predicted ED stress positivity in multivariate analysis.Conclusions:Comparison of a validated instability scoring system with ED stress examination of minimally displaced LC1 fractures in awake and hemodynamically stable patients showed excellent correlation. This suggests that the ED stress examination is a useful diagnostic adjunct. LC1 fracture characteristics should be analyzed to determine which pelvic fracture characteristics determine occult instability before stress examination.Level of Evidence:Level III diagnostic.