Clinical Outcomes of Straddle Fracture Patterns: A Retrospective Multicenter Analysis Based on a New Descriptive Classification Framework

초록

Background: Straddle fractures involving bilateral pubic rami are complex pelvic ring injuries resulting from high-energy trauma. Existing classifications primarily focus on posterior ring injuries, often overlooking the anterior ring's contribution to pelvic instability. This study aimed to describe and analyze straddle fracture patterns and their associated clinical outcomes using a newly proposed framework that integrates both anterior and posterior pelvic ring components. Methods: A retrospective multicenter cohort study was conducted involving 203 patients treated for straddle fractures at 3 level I trauma centers between March 2015 and December 2021. Fractures were categorized into 3 grades according to anterior and posterior ring involvement, ramus displacement, and pelvic instability. Management strategies ranged from conservative care to combined anterior-posterior fixation. Radiological and functional outcomes were assessed, and logistic regression analysis identified factors associated with complications. Reliability was evaluated using kappa statistics. Results: Treatment strategies showed high concordance with the proposed framework (86%, 90%, and 88% for grades I, II, and III, respectively). Interobserver (Fleiss' kappa = 0.65) and intraobserver (Cohen's kappa = 0.73) reliability demonstrated substantial agreement. Anatomic reduction (<= 4 mm displacement) was achieved in 78.7%, 55.7%, and 45.5% of grades I-III, respectively (p = 0.009). Complication rates increased with grade severity (6.4%, 13.9%, and 22.1%; p = 0.057). Age (odds ratio [OR], 1.049; p = 0.006), Injury Severity Score (OR, 1.113; p < 0.001), and fracture grade independently predicted complications. Conclusions: This new descriptive classification framework provides a reproducible and clinically relevant method for stratifying straddle fracture severity and prognosis. While not intended as a prescriptive treatment algorithm, it demonstrates strong reliability and meaningful correlations between grade, radiological alignment, and complication risk. Higher-grade fractures were associated with greater instability and poorer outcomes, underscoring the importance of individualized management strategies and the need for future prospective and biomechanical validation.

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