High Rate of Missed Geriatric U-Type Sacral Fractures Despite Advanced Imaging: A Retrospective Case Series

OBJECTIVES: To determine the rate of missed diagnoses among geriatric patients with low-energy U-type sacral fractures. METHODS: Design : Retrospective case series. Setting: Two academic Level 1 trauma centers. Patient Selection Criteria: All patients ≥65 years with sacral fractures between January 2023 and January 2025 were screened using CPT and ICD codes. Provider notes, radiology reports, and available pelvic/sacral advanced imaging (CT and/or MRI) were reviewed. Patients with low-energy U-type sacral fractures (OTA/AO 55C0 or 54C3) confirmed by study team review of advanced imaging were included. Outcome Measures and Comparisons: The primary outcome was the rate of missed U-type fractures, defined as fractures not diagnosed by any provider at the first clinical encounter in which advanced imaging demonstrated a U-type fracture, as identified on study team review. Missed U-type fractures were subclassified as: initial misses (visible on advanced imaging at the initial encounter but not diagnosed), delayed imaging misses (no advanced imaging at the initial encounter and not diagnosed at the first subsequent encounter with advanced imaging), and evolving misses (not present or visible on initial advanced imaging but visible on subsequent imaging and not diagnosed). Complete misses were U-type fractures never diagnosed during clinical care. RESULTS: Among 262 geriatric sacral fractures screened, 69 (26.3%) were low-energy U-type fractures (median age 79 years; 81% female) confirmed by the study team. Of these, 25 (36.2%) were missed and 44 (63.8%) were not missed. Among missed fractures, 16 (64.0%) were initial misses, 6 (24.0%) were delayed imaging misses, and 3 (12.0%) were evolving misses. Overall, 14 (56.0%) were complete misses (9 initial misses, 2 delayed imaging misses, 3 evolving misses), while 11 were subsequently recognized by a provider (7 initial misses, 4 delayed imaging misses). CONCLUSIONS: More than one-third of geriatric U-type sacral fractures were missed despite advanced imaging. This reinforces the need for heightened clinical vigilance and careful advanced imaging review to facilitate timely diagnosis and appropriate management of these injuries. LEVEL OF EVIDENCE: Diagnostic Level III