Objective:

To evaluate the association between routine intraoperative microbiological screening and implant survival in presumed aseptic revision arthroplasty, and to identify potential predictors of unexpected PJI.

Approach:

• Study Design: A retrospective matched cohort study conducted at a single tertiary referral center from 2013 to 2019, comparing screened and unscreened cohorts of patients undergoing hip and knee revisions.
• Patient Cohorts: The screened cohort included patients with routine intraoperative microbiological screening, while the unscreened cohort included patients without such screening, matched for sex, age, diagnosis, and procedure type.
• Microbiological Analysis: Intraoperative samples were collected for microbiological analysis, and patients received standard antibiotic prophylaxis until results were available.

Key Findings:

• Up to 9.2% of presumed aseptic revision patients had at least one intraoperative unexpected positive culture (UPC).
• The clinical significance of a single UPC remains debated, with some studies indicating it may not lead to subsequent PJI.
• No universally accepted thresholds or management strategies exist for patients with UPCs.

Interpretation:

The study highlights the complexity of diagnosing PJI in presumed aseptic revisions and questions the utility of routine intraoperative screening.

Limitations:

• The study is retrospective and conducted at a single center, which may limit generalizability.
• Exclusion of patients with a history of infection may affect the findings.

Conclusion:

The findings suggest a need for further investigation into the clinical relevance of unexpected PJIs in presumed aseptic revisions.