Risk of surgical site infections following hip and knee arthroplasty: results of the ISChIA-GISIO study

Background. Surgical Site Infection (SSI) is one of the major complications following insertion of hip or knee prosthesis. The aim of the present study was to describe rates of SSIs and associated risk factors during hip and knee prosthesis procedures in Italian hospitals. Methods. Italian hospitals were invited to join the ISChIA (Surgical Site Infections in Arthroplasty Surgery) project and participated in the study on a voluntary basis. SSI surveillance was performed according to the Hospitals in Europe Link for Infection Control through Surveillance (HELICS) -SSI protocol. The study population consisted of all patients who had a prosthetic knee or hip joint replacement between March 2010 and February 2011. Only elective operations were included. Results. A total of 14 hospitals and 1285 surgical procedures were included. SSI cumulative incidence was 1.3 per 100 hip and 2.4 per 100 knee surgical procedures; a significant positive trend of SSI incidences was observed with increasing SSI risk index. In multivariate analysis, considering hip procedures, the single independent risk factor associated to SSI was operation length (RR: 4.54; 95%CI: 1.06-19.48). For knee procedures, no significant risk factor was identified. Conclusions. In the present study, SSI cumulative incidence was in the range of European data. However, a larger number of operations is needed to better estimate SSI rates. A second edition of the ISChIA project has been already conducted and results of the two surveys will provide new insight to further our knowledge for infection control.