Sacral U-Type Fractures: A Comparative Study of Treatment Approaches

Study Design: Retrospective Cohort Study. Objectives: To evaluate clinical and patient reported outcomes between operative and non-operative management strategies for sacral U-type fractures. Methods: This retrospective review included patients with sacral U-type fractures from a 12-year period at a Level 1 trauma center. Demographic, Modified 5-Item Frailty Index (mFI-5), complications, outcomes, and Patient-Reported Outcomes Measurement Information System (PROMIS) data were collected. Fractures were classified by the AO Spine Sacral Injury Classification System (AOSSIC) and analyzed by subtype and treatment modality (trans-sacral screw fixation (TSF) or lumbopelvic fixation (LPF) vs non-operative). Statistical significance was P < .05. Results: Sixty-five patients met inclusion criteria (mean age 59.7 ± 21.3 years, 49% male). Forty-seven (72%) were treated operatively (10 LPF, 37 TSF) and 18 non-operatively. Among C0 fractures, PROMIS Pain Interference (PI) and Physical Function (PF) scores were similar between operative and non-operative groups (62.96 vs 66.08, P = .48; 30.01 vs 32.40, P = .62). Similar findings were observed for C3 fractures (PI 62.62 vs 64.23, P = .58; PF 30.29 vs 29.3, P = .78). mFI-5 frailty scores were higher among non-operative C3 fracture patients compared to operative cases (2.25 vs 0.90, P < .001). Complication rates were low and comparable between groups. Symptomatic screw removal occurred in 8% of TSF cases. Conclusions: Operative and non-operative management of AOSSIC Type C sacral fractures yield comparable PROMIS outcomes and complication rates when frailty scores are considered. TSF was associated with higher rates of symptomatic screw removal. Further investigation is needed to determine the optimal treatment and impact of frailty metrics for these injuries.