Open tibial fractures : risk factors for infection in conversion of external fixator to intramedullary nail at a tertiary academic hospital

Abstract

AIM : To determine the rate of infection in open tibial fractures treated by conversion of an external fixation into an intramedullary nail, and to identify the factors contributing to the infections. METHODS : The study included a total of 52 patients. Multiple variables were assessed as risk factors that could lead to infection in open tibial fractures treated primarily with an external fixator and later converted into an intramedullary nail. The factors looked at were: age, average time taken from injury to debridement, average time taken from admission to debridement, antibiotics administration, facility that admitted the patient before intramedullary nail, average time for conversion of external fixator into intramedullary nail insertion, type of soft tissue management, initial Gustilo and Anderson classification and retrospective re-classification of fractures, existence of superficial sepsis or pin-tract infection, radiologic evidence of infection, the Injury Severity Score and the type of external fixator used. A p value < 0.05 was used as the threshold for level of significance. RESULTS : The average follow-up was 37 weeks (median 24 weeks). We had a 40% infection rate CI [27%, 55%]. Factors that were found to be the most statistically significant (p≤0.05) were amount of soft tissue injury and fracture comminution; this is after the fractures were retrospectively re-classified. All other factors looked at were not statistically significant as risk factors for infection (p>0.05). CONCLUSION : The study suggests that correct classification of open tibial fractures, with recognition of soft tissue injury and bone comminution, is important in reducing infection rates and in ensuring proper initial management of these fractures. Treatment should be based on the classification done in theatre during the initial debridement, rather than on presentation in the trauma unit.