Fixation Strategy Using Sequential Intraoperative Examination Under Anesthesia for Unstable Lateral Compression Pelvic Ring Injuries Reliably Predicts Union with Minimal Displacement

Background: Examination under anesthesia (EUA) has been used to identify pelvic instability. Surgeons may utilize percutaneous methods for posterior and anterior pelvic ring stabilization. We developed an intraoperative strategy whereby posterior fixation is performed, with reassessment using sequential EUA to determine the need for anterior fixation. Our aim in the current study was to evaluate whether this strategy reliably results in union with minimal displacement. Methods: This was a multicenter retrospective study involving adult patients with closed lateral compression (LC) pelvic ring injuries treated during the period of 2013 to 2016. Included were patients who underwent percutaneous pelvic fixation based on sequential EUA. Data points included patient demographics, injury and fixation details, and displacement as observed on follow-up radiographs. Results: Complete documentation was available for 74 patients (mean age, 41 years). The mean duration of follow was 11 months. Fifty-three of the patients had LC-1 injuries, 19 had LC-2 injuries, and 2 had LC-3 injuries. Twenty-five (47.2%) of the 53 patients with LC-1 and 11 (57.9%) of the 19 patients with LC-2 injuries did not undergo anterior fixation on the basis of the algorithm. The 36 LC-1 or LC-2 patients who underwent combined anterior and posterior fixation had no measurable displacement at union. Of the 36 LC-1 or LC-2 patients with no anterior fixation, 27 with unilateral rami fractures had no measurable displacement at union. The remaining 9 LC-1 or LC-2 cases with no anterior fixation had bilateral superior and inferior rami fractures; each of these patients demonstrated displacement (mean, 7.5 mm; range, 5 to 12 mm) within 6 weeks of fixation that remained until union. All patients had protected weightbearing for 12 weeks. Conclusions: A fixation strategy based on sequential intraoperative EUA reliably results in union with minimal displacement for unstable LC pelvic ring injuries. Injuries requiring combined anterior and posterior fixation healed with no displacement. Those without anterior fixation and a unilateral ramus fracture healed with no displacement. In the presence of bilateral rami fractures, even with a negative finding on sequential EUA, the pelvis healed with 7.5 mm average displacement. Surgeons may consider anterior fixation to prevent this displacement.