Functional outcomes after conservative management of APC-1 pelvic ring injuries with negative examination under anesthesia: a follow-up case series

Anterior–posterior compression type-1 (APC-1) pelvic ring injuries with a negative examination under anesthesia (EUA) are usually managed non-operatively; however, long-term patient-reported outcomes are unclear. We evaluated the functional outcomes after conservative care and explored radiologic and mechanical correlations. This case series was conducted within a prospective cohort to evaluate EUA in APC-1 pelvic ring injuries. Adults with negative EUA (symphyseal opening <25 mm) managed non-operatively between April 2016 and June 2023 were included. Minimum follow-up was 12 months. The primary outcome was the SF-36 Physical Component Summary (PCS). "poor–fair" function was defined as PCS <61. Exploratory analyses evaluated associations between SF-36 and (i) anterior SI ligament injury on MRI, (ii) dynamic symphyseal opening during EUA, and (iii) initial SI joint diastasis on radiography. Nine men (median age 41 years, range 32–61) were analyzed at a mean follow-up of 51 months (range 13-99). Four of the nine (44%) patients reported poor–fair function. Anterior SI ligament injury, present in five patients (56%) was associated with lower SF-36 PCS (median 60 vs. 90; p=0.175), representing alarge effect size (Cohen’s d 0.87). Neither dynamic symphyseal opening nor initial SI diastasis showed a clear association with SF-36 PCS. Even with a negative EUA, a substantial proportion of APC-1 patients have suboptimal long-term function after conservative treatment. MRI-defined anterior SI ligament injuries may help identify high-risk patients and should be considered in counseling and follow-up. However, larger cohorts are required to validate these findings.