Globulin, albumin to globulin ratio, and plasma fibrinogen may be potential diagnostic biomarkers for tibial infected nonunion

The accurate preoperative diagnosis of infected nonunion remains challenging. Here, we evaluated the diagnostic potential of novel biomarkers for tibial infected nonunion. A single-center retrospective study was conducted on 155 patients divided into two groups: 59 with tibial infected nonunion (Group A) and 96 with tibial aseptic nonunion (Group B). Preoperatively analyzed clinical parameters included plasma D-dimer, plasma fibrinogen, albumin (ALB), globulin (GLB), albumin-to-globulin ratio (AGR), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and white blood cell (WBC) count. Receiver operating characteristic (ROC) curves, sensitivity, and specificity were utilized to compare the diagnostic potential of these biomarkers. The WBC, ESR, CRP, plasma D-dimer, plasma fibrinogen, and GLB levels of Group A were significantly higher (P < 0.05) than in Group B. The ALB and AGR levels of Group A were significantly lower (P < 0.05) than in Group B. The area under the curve (AUC) of ESR, plasma fibrinogen, and AGR were greater than 0.8. An analysis of a combination of ESR, plasma fibrinogen, GLB, and AGR had the highest AUC. In patients with comorbidities, the diagnostic accuracy of ESR, plasma fibrinogen, GLB, and AGR also performed well. Higher levels of WBC, CRP, and ESR were detected in patients who had recently used antibiotics (P < 0.05). GLB, AGR, and plasma fibrinogen are promising biomarkers for improving the diagnosis of tibial infected nonunion. The integrated analysis of ESR, plasma fibrinogen, GLB, and AGR provided more accurate and more specific diagnosis than the four biomarkers individually.