Variables associated with loss of reduction after plate fixation of pubic symphysis injuries.

Abstract

To determine what variables are associated with loss of reduction of pubic symphysis injuries after plate fixation. A retrospective review of patients treated with plate fixation of symphysis injuries was performed. Symphysis diastasis on injury, postoperative, and follow-up radiographs was measured. Associations between patient, fracture, and fixation characteristics and a loss of reduction ≥10 mm were analyzed. Fifty patients were included. The median age was 38.5 years (IQR 27.7 to 48.5), and a majority were male (80.0%, n=40). A loss of reduction ≥10 mm occurred in 18% (n=9), and revision fixation occurred in 6.0% (n=3). On univariate analysis, patients with a loss of reduction, compared to patients without, had a greater BMI (32.2 vs. 26.5, p=0.001), increased symphysis diastasis on injury radiographs (46.0 vs. 24.0 mm, p=0.0001), and more anterior pelvic space infections (55.6% vs. 14.6%, p=0.01). There were no associations between loss of reduction and age, AO/OTA classification, Young Burgess classification, 4-screw vs. >4-screw plate fixation, number of posterior screws, or residual post-fixation symphyseal diastasis (p>0.05). On multivariate analysis, initial symphysis diastasis was the only variable associated with loss of reduction ≥10 mm (p=0.03). A symphysis diastasis of ≥35.0 mm was found to maximize the sensitivity (88.9%) and specificity (75.7%) for identifying patients who had a loss of reduction. The severity of initial symphysis diastasis was associated with loss of reduction. A threshold of 35.0 mm of symphysis diastasis maximized the sensitivity and specificity for identifying patients who experienced a loss of reduction. Retrospective comparative study, Level III evidence.