Surgical Site Infections After Primary Total Knee Arthroplasty: A Retrospective Cohort Study and Critical Assessment of the French ISO-ORTHO Surveillance Indicator.

Background/Objectives: Prosthetic joint infection following total knee arthroplasty remains a significant public health challenge. Automated surveillance systems are increasingly used for national monitoring of surgical site infections after arthroplasty. This study assessed the performance of the French ISO-ORTHO automated surveillance indicator after primary total knee arthroplasty by comparing automated surveillance data with exhaustive clinical follow-up. It also reported the incidence of surgical site infections during the initial years of activity of a tertiary care university hospital. Methods: A retrospective cohort analysis of primary total knee arthroplasties performed between January 2016 and December 2018 was conducted using exhaustive clinical chart review and the French ISO-ORTHO automated surveillance system. Prosthetic joint infections were diagnosed according to the 2018 International Consensus Meeting criteria. The local ISO-ORTHO results were compared with the national ISO-ORTHO rates. Results: Clinical chart review identified 1138 primary total knee arthroplasties and five prosthetic joint infections. Prosthetic joint infection incidence was 0.44% with a mean follow-up of 40.5 months. ISO-ORTHO was not yet implemented in 2016. Between 2017 and 2018, ISO-ORTHO identified 519 procedures and one prosthetic joint infection, compared with 807 procedures and three infections identified by clinical review. Conclusions: The French ISO-ORTHO surveillance indicator aided local and national monitoring of surgical site infections after total knee arthroplasty, but discrepancies with clinical chart review highlighted important limitations of automated monitoring and the importance of prolonged clinical follow-up. Future surveillance strategies could integrate these complementary approaches to improve prosthetic joint infection detection.