Incidence and predictors of surgical site infection after ORIF in calcaneus fractures, a retrospective cohort study

Background: Occurrence of calcaneus fractures is on the up trend. Owing to its unique anatomical morphology and limited soft-tissue envelope, management of calcaneus fractures is a challenge to the orthopaedic surgeon, and surgical site infection (SSI) is one of the serious postoperative complications. In order to decrease the incidence of wound breakdown and improve clinical outcomes, it is necessary to understand which factors were associated with SSI. The aim of this study was to identify predictors of SSI and quantify the incidence of SSI in calcaneus fractures following open reduction and internal fixation (ORIF). Methods: This retrospective study was performed at a level 1 trauma center from January 2014 to June in 2017. Data of adult patients with calcaneus fractures treated by ORIF were extracted from the electronic medical records. A total of 681 patients were collected. We reviewed the patients' demographics, characteristics of fracture, treatment-related variables, and indexes of laboratory examination. Univariate and multivariate logistic analysis models were performed respectively to determine independent predictors of SSI. Results: Sixty-six patients developed SSI in this study. The overall incidence of SSI after ORIF of calcaneus fracture was 9.7%, with 2.9% for deep infection and 6.8% for superficial SSI. Independent predictors of SSI identified by multivariate analysis were open fracture (odds ratio=9.48, 95% CI=4.53-19.85, P = 0.00007), high-energy injury (odds ratio = 2.07, 95% CI = 1.16-3.70, P = 0.01437), ASA class 3 or higher (odds ratio = 3.50, 95% CI = 1.18-10.37, P = 0.02401), and intraoperative temperature <36.0 degrees C (odds ratio = 1.69, 95% CI = 1.13-2.28, P = 0.04410). Conclusion: The SSI incidence was high (9.7%) for calcaneus fractures following ORIF. External fixation plays an important role in the treatment of severely displaced and depressed intra-articular or open calcaneus fractures. Increased ASA class and intraoperative hypothermia were associated with wound breakdown, and elaborative evaluation of fracture and soft-tissue damage was vitally necessary in this at-risk population.