Performance of the OTA-OFC3 Classification System for Open Fractures

BACKGROUND: The purpose of this study was to compare the simplified modification of the Orthopaedic Trauma Association-Open Fracture Classification (OTA-OFC3) with the original OTA-OFC and Gustilo-Anderson classification systems in predicting surgical site infection and unplanned reoperation. METHODS: This was a retrospective cohort study conducted using the PREP-IT (A Program of Randomized Trials to Evaluate Preoperative Antiseptic Skin Solutions in Orthopaedic Trauma) trial data of patients with open fractures. The OTA-OFC and Gustilo-Anderson classifications for each included fracture were determined by the treating surgeon at the initial irrigation and debridement. The OTA-OFC3 classification was determined on the basis of the highest severity level in any OTA-OFC domain. The study outcomes included surgical site infection and unplanned reoperations within 1 year of injury. Prognostic performance was measured by the area under the receiver operating characteristic curve (AUC), and AUCs were compared between classifications with z-tests. RESULTS: This cohort study included 3,338 patients with 3,627 open fractures. Surgical site infections occurred for 11% of the open fractures, and unplanned reoperations occurred for 15%. The prognostic performance of the new OTA-OFC3 score (AUC, 0.61; 95% confidence interval [CI], 0.58 to 0.64) did not differ significantly from that of the Gustilo-Anderson classification (AUC, 0.63; p = 0.40) or the 5 OTA-OFC domains (AUC, 0.64; p = 0.32) in predicting surgical site infection. The prognostic performance of the OTA-OFC3 system (AUC, 0.62; 95% CI, 0.59 to 0.64) was similar to that of the Gustilo-Anderson classification (AUC, 0.63; p = 0.34) but was significantly worse than that of the 5 OTA-OFC domains (AUC, 0.69; p < 0.001) in predicting unplanned reoperations. CONCLUSIONS: Simplifying the OTA-OFC to the new OTA-OFC3 significantly decreased its ability to predict unplanned reoperations and did not improve the ability to predict surgical site infection. These findings indicate that this newly proposed classification system, although clinically simpler, omits important prognostic information captured in the original OTA-OFC. Despite this limitation, the OTA-OFC3 demonstrated prognostic performance similar to that of the commonly used Gustilo-Anderson classification, and it may provide a clinically convenient way to communicate critical OTA-OFC information when all OTA-OFC domains are being assessed for research or quality-improvement purposes. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.