Post-discharge surveillance of surgical site infections after total hip and knee arthroplasty

Abstract number: P1903

Mitt P., Telling K., Adamson V., Rõõm M., Kolk H., Märtson A., Maimets M.

Objective: The aim of the study was to investigate the surgical site infection (SSI) rate after total hip (THA) and total knee (TKA) arthroplasties using postdischarge surveillance.

Methods: From January to June 2007 a total of 553 patients were evaluated after THA (n = 253) and TKA (n = 300) in Tartu University Hospital. SSI was identified according to the National Nosocomial Infection Surveillance system (NNIS) criteria during hospital stay and for 12 months postdischarge using telephone calls, laboratory data and medical record review. Potential prophylaxis-, patient-, and procedure-related risk factors were also collected prospectively.

Results: A total of 8 SSIs were identified. SSI was recorded in 5 patients after THA (cumulative incidence rate 2.4%): 3 deep or organ/space and 2 superficial SSIs. After TKA 3 SSIs were identified (cumulative incidence rate 1.0%): 1 organ/space and 2 superficial SSIs. Most of the operations were performed in patients with the NNIS risk index category 0 or 1 (47.0% or 51.4%, respectively). The incidence of SSI in THA and TKA stratified according to the NNIS risk index was 2.26% and 1.57% (NNIS = 0), and 1.72% and 0.59% (NNIS = 1), respectively. The total response rate to the telephone questionnaire survey was 95.3% and 2 out of three SSIs detected by telephone questionnaire were superficial. All the other cases were detected on readmission. The median length of hospital stay after operation was 5 days (range 3–24 days). Time between operation and detection of SSI cases ranged from 14 to 356 days. 72.1% of patients received antibiotic prophylaxis within 30–60 min before incision.

Conclusions: Although our numbers are small, all SSIs were identified using postdischarge surveillance. In our centre the incidence of SSI in risk index category 0 is higher than the notified incidence in the Hospitals in Europe Link for Infection Control Through Surveillance or NNIS system which needs further investigation.