Underestimation Posterior Ring Involvement in Fragility Pelvic Fractures with Anterior Ring Compromise

Fragility pelvic fractures (FPF) are an increasing issue in our aging population.Radiography is the most commonly used examination for initial diagnosis, however, it may underestimate posterior ring injuries.Objective: to evaluate radiographic underestimation of posterior ring fractures in patients with FPF and isolated anterior ring fracture.Materials and Methods: a prospective study was conducted at two trauma centers with patients diagnosed with FPF from 2019 to 2022.We Included individuals over 60 years old with isolated anterior ring fracture confirmed radiographically and attributed to low-energy mechanisms.Bedridden patients and pelvic fractures in tumoral bone were excluded.Selected individuals underwent a pelvic computed tomography (CT) to search for hidden posterior ring fractures.Results were compared and associated with demographic and clinical data through statistical model analysis, hypothesis testing, and machine learning models.Results: out of 264 diagnosed with FPF, 58 met inclusion and exclusion criteria.In pelvic CT, hidden posterior ring fracture was found in 65% of cases.Average age was 81.7 years (SD = 9.49 years), and 87.9% of cases were women.Of recorded patients, 32% presented with posterior sacral pain, and 48% retained the ability to walk at the time of their first emergency consultation.The most common initial classification of FPF by Rommens was Ia, followed by Ib.After CT, predominant classification was 2b (39.6%) followed by Ia (29.3%).On statistical analysis, no significant association was found between hidden posterior ring involvement and age, sex, sacral pain, walking ability, or time from onset at first consultation. Conclusion:Every patient with FPF with isolated anterior ring involvement needs a pelvic CT in their initial evaluation, given the low diagnostic accuracy of radiography for diagnosing posterior ring fractures.This practice should be maintained independent of findings in the medical interview and physical examination.