Hyperglycemia as a risk factor for postoperative early wound infection after bicondylar tibial plateau fractures: Determining a predictive model based on four methods

Objectives: Identify a glucose threshold that would put patients with isolated bicondylar tibial plateau fractures at risk of early wound infection (i.e. < 90 days). Design: Retrospective review of medical records. Setting: Academic American College of Surgeons (ACS) Level 1 trauma center. Patients: Adult patients between 2010 and 2015 with an operatively treated isolated bicondylar tibial plateau fracture and at least three glucose measurements during their hospitalization. Main Outcome Measurement: To predict infection using four different methods: maximum preoperative blood glucose (PBG), maximum blood glucose (MGB), Hyperglycemic Index (HGI), and Time-Weighted Average Glucose (TWAG). Results: 126/381 patients met our inclusion criteria. Fifteen (12%) patients had an open fracture and 30/126 (23%) developed an infection. Median glucose for each predictive method studied was 114 (IQR 101.2–137.8) mg/dL for PBG, 144 (IQR 119–169.8) mg/dL for MBG, 0.8 (IQR 0.20–1.60) mmol/L for HGI, and 120.4 (IQR 106.0–135.6) mg/dL for TWAG. As expected, infected patients had higher PBG, MGB, and TWAG. HGI was similar in both groups. None of these differences prove to be statistically significant (p > .05). Logistic regression models for all the methods showed that having an open fracture was the strongest predictor of infection. Conclusion: It is well known that stress-induced hyperglycemia increases the risk of infection, we present and compare four models that have been used in other medical fields. In our study, none of the methods presented identified a glucose threshold that would increase the risk of infection in patients with bicondylar tibial plateau fractures. Level of Evidence: Retrospective review, Level III. See Instructions for Authors for a complete description of levels of evidence.