Selective Anterior Fixation for Rami Fractures in Anteroposterior Compression-Type Pelvic Ring Injuries: Impact of Posterior Stability.

Background/

Objectives

Rami fractures in anteroposterior compression (APC)-type pelvic ring injuries show favorable outcomes with conservative management in isolated settings; however, the necessity of direct rami fixation when posterior instability is present remains unclear. This study aimed to determine whether adding direct rami fixation to symphyseal plating improves clinical and radiologic outcomes in APC-type pelvic ring injuries.

Methods

This retrospective cohort study included a final cohort of 98 patients with APC type II or III pelvic ring injuries and concomitant pubic rami fractures treated at a Level 1 trauma center (2014-2022). All patients underwent plate-based symphyseal fixation, classified into four groups by fixation strategy. Primary outcomes were rami nonunion and implant-related complications, analyzed with parsimonious multivariate logistic regression (events-per-variable ratio ≥ 10).

Results

Among 98 patients (mean age 45.4 ± 16.2 years; 76.5% male), complete posterior ring injury was independently associated with rami nonunion (aOR 8.176; 95% CI 2.448-27.309; p = 0.001), implant-related complications (aOR 3.364; 95% CI 1.250-9.049; p = 0.016), and overall complications (aOR 4.292; 95% CI 1.640-11.233; p = 0.003). Female sex was an additional independent predictor of overall complications (aOR 4.226; 95% CI 1.443-12.378; p = 0.009). Direct rami fixation was not a significant predictor of any outcome but consistently increased operative time in pairwise subgroup comparisons (Group 1 vs. 2: 64.9 vs. 106.9 min, p < 0.001; Group 3 vs. 4: 95.1 vs. 153.5 min, p < 0.001). Pairwise subgroup comparisons were severely underpowered (power range 5-16%); therefore, the absence of statistically significant differences between fixation strategies should not be interpreted as evidence of equivalence. Because more complex fractures were more likely to receive additional fixation, confounding by indication further limits these comparisons.

Conclusions

Complete posterior ring injury was the dominant predictor of adverse outcomes in APC-type pelvic ring injuries. In this underpowered exploratory analysis, adding direct rami fixation to symphyseal plating did not demonstrate a statistically significant reduction in complications but was associated with longer operative time. Direct rami fixation may be reserved for selected cases with marked displacement, poor indirect reduction, or compromised bone quality; larger prospective studies are needed before firm recommendations can be made.