Risk Factors for Infection Following Operative Treatment of Traumatic Upper Extremity Amputation Injury

Background: Identification of the risk factors for surgical site infection (SSI) can be a straightforward and cost-effective measure to reduce or prevent the occurrence of SSI. However, there are no studies that revealed risk factors for SSI for traumatic upper extremity amputation. The aim of this study is to investigate the risk factors that promote SSI after surgery for traumatic upper extremity amputation using a large nationwide database. Methods: We used data from the Japan Trauma Data Bank. Diagnoses were defined using the Abbreviated Injury Scale code. We applied multivariate logistic regression to evaluate the infection risk factor. We chose age, sex, vital signs, cause and type of trauma, concomitant injury, diabetes, amputation level, Glasgow coma scale, Injury Severity Score (ISS) and blood transfusion within 24 hours following hospital arrival as confounders. Receiver operating characteristic (ROC) curve analysis was adopted to identify thresholds for change in infection risk. We also applied propensity score (PS) matching to adjust for confounding factors that may affect the outcome. Results: A total of 1,150 patients (967 males, 183 females) had traumatic upper extremity amputation. The mean patient age was 46.5 years. A total of 21 patients (1.8%) suffered from SSI. ISS, blood transfusion, systolic blood pressure (BP) and the upper extremity amputation except for finger were identified as the independent significant risk factors for SSI occurrence by the multivariate analysis (p < 0.05, p < 0.005, p < 0.05 and p < 0.005, respectively). ROC modelling revealed that patients with ISS of over 9 or systolic BP of over 160 had a risk for SSI. After PS matching, the patients with blood transfusion or systolic BP of over 160 had a significantly higher risk of infection (OR 9.0; p = 0.01 and OR 7.0; p = 0.03, respectively). Conclusions: In treating patients with these risk factors, we must be especially careful in performing thorough debridement and wound care. Level of Evidence: Level II (Therapeutic).