Combination of albumin-to-globulin ratio and plasma fibrinogen is a sensitive tool for preoperative screening of infected nonunion in patients undergoing reoperation after open reduction and internal fixation: a retrospective study

BACKGROUND: Accurate preoperative diagnosis of infected nonunion remains a challenge. Here, we evaluated the diagnostic potential of novel biomarkers for infected nonunion. METHODS: A cohort of 275 patients who underwent surgery for suspected septic nonunion after open reduction and internal fixation were enrolled. Preoperatively analyzed clinical parameters included white blood cell (WBC) count, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), albumin, globulin, albumin-to-globulin ratio (AGR), plasma D-dimer, plasma fibrinogen, platelet count (PC), monocyte-lymphocyte ratio (MLR), neutrophil–lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR). Receiver operating characteristic (ROC) curves, sensitivity, and specificity were utilized to compare the diagnostic potential of those biomarkers. RESULTS: The WBC count and levels of CRP, ESR, NLR, MLR, PLR, PC, plasma D-dimer, plasma fibrinogen, and globulin in infected nonunion patients were significantly higher (p < 0.05) than those in aseptic patients. The albumin and AGR levels of the infected nonunion group were significantly lower (p < 0.05) than the aseptic group. The ROC curve analysis showed that the diagnostic accuracy of AGR and plasma fibrinogen was good. The combination of AGR with plasma fibrinogen had the highest area under the curve (AUC) (0.916). The sensitivity and specificity were 70.27% and 91.04% for AGR, and 67.57% and 84.08% for plasma fibrinogen, respectively. The combination of AGR with plasma fibrinogen showed a sensitivity of 86.49% and specificity of 92.54%. In patients with comorbidities, the diagnostic accuracy of the combination of AGR with plasma fibrinogen was also good. CONCLUSIONS: AGR and plasma fibrinogen are promising biomarkers to improve the diagnosis of infected nonunion. The combination of AGR with plasma fibrinogen is a sensitive tool for screening infected nonunion.