Factors related to infection after fixation in the process of late healed bone fracture.

We studied the factors related to infection after fixation in the process of bone late healed fracture and explored the factors that could predict the risk of postoperative infection. A total of 100 patients with open fractures of the tibia and fibula diagnosed in Zhengzhou No. 7 People's Hospital from 2007 to 2016 were enrolled in this study. Patients were subjected to staging surgery treatment. We divided them into the infection group (n=52) and the non-infection group (n=48) according to whether or not infection occurred after operation. Pearson correlation was used to analyze the relationship between postoperative infection and preoperative factors, and ROC curve was used to explore the factors which could predict the risk of postoperative infection. As a result, surgical timing and C-reactive protein were correlated with postoperative infection (P<0.05), and surgical timing was negatively correlated with postoperative infection. C-reactive protein was positively correlated with postoperative infection. Using 7 days as the cut-off point of surgical timing, false positive and false negative rates were 0 and 27.7%, respectively. Youden index value was 72.3%, and positive predictive and negative predictive values were 42.5 and 100%, respectively. With 54.55 mg/l as the cut-off point of C-reactive protein, the sensitivity and specificity of prediction were 88.2 and 94.1%, while the false negative and false positive rates were 11.8 and 5.9%, respectively. The Youden index value was 82.3%, and the positive predictive and negative predictive values were 75 and 96.7%, respectively. With 7 days as the cut-off point of surgical timing and 54.55 mg/l as the cutoff point of C-reactive protein at the same time, the positive predictive and negative predictive values were 88.2 and 97.6%, respectively. The false negative and false positive rates were 11.8 and 2.4%, respectively. The Youden index value was 85.8%. The positive predictive and negative predictive values were 88.2 and 97.6%, respectively. In conclusion, surgical timing and C-reactive protein were strongly correlated with postoperative infection and this correlation was not affected by age, sex or other inflammatory indexes. The incidence of postoperative infection was reduced when both factors were applied for the determination of surgery. In addition, incidence of complications will be reduced and the cure rate improved.