To analyze the risk factors of surgical site infection(SSI) in patients undergoing primary total knee arthroplasty(TKA).

A retrospective analysis was performed on the general date of all 1462 patients who underwent primary total knee arthroplasty due to knee osteoarthritis in the third department of orthopedics, General Hospital of Ningxia Medical University from January 1, 2011 to December 31, 2018. According to the definition, the patients undergoing primary TKA were included, those undergoing revision surgery were ecluded. Twenty-eight cases in the SSI group and 1 434 cases in the non-SSI group were screened respectively.Age, gender, body mass index(BMI), urine test results, the length of hospital stay and allogeneic blood transfusion of the two groups were collected and included in the study.Comorbidity such as diabetes, rheumatoid disease, pulmonary infectious disease, cardiovascular disease, lower extremity vascular disease, liver disease (viral hepatitis, cirrhosis, etc.) were calculated. Logistic regression analysis for the odds ratio(OR) and 95% confidence interval(CI) was used to determine the influencing factors.

The overall infection rate of the surgical site after total knee arthroplasty in this study was 1.9%. Logistic regression analysis showed that allogeneic blood transfusion [OR=6.567, 95%CI(2.558, 16.858)], long-term hormone use history before surgery[OR=20.071, 95%CI(2.678, 150.404)], hospitalization time ≥14 days before surgery[OR=5.699, 95%CI(1.615, 20.111)], asymptomatic bacterial urine[OR=3.572, 95%CI(1.128, 11.312)], combined with pulmonary infectious diseases[OR=11.705, 95%CI(3.794, 36.105)](COPD, etc.) and liver disease[OR=5.848, 95%CI (2.034, 16.814)](viral hepatitis, cirrhosis, etc.) were influential factors for SSI(P<0.05).

The risk factors for surgical site infection after primary total knee arthroplasty are complicated, and effective measures should be taken to prevent SSI after surgery.