Background:

Pre-incision antibiotic prophylaxis reduces the risk of infection in total knee arthroplasty, but its role during revision surgery for periprosthetic joint infection (PJI) remains uncertain.

Methods:

Retrospective multicenter study of 576 patients with chronic knee PJI treated with two-stage exchange arthroplasty and ≥1 year follow-up.

PJI was defined using the 2013 Musculoskeletal Infection Society (MSIS) criteria.

Patients without preoperative synovial aspiration or receiving outpatient antibiotics within 2 weeks of aspiration or revision surgery were excluded (n=182).

Preoperative aspirate cultures, intraoperative tissue cultures, and prophylactic antibiotic regimens were recorded.

Prophylaxis was administered before incision in 49% and withheld in 51%. 

Results:

Overall intraoperative culture positivity was identical with early versus delayed prophylaxis (63% vs. 63%, p=0.960).

 Aspirate-to-tissue concordance was also similar (85 versus 80%, P = 0.225).

Among patients with positive preoperative aspiration, antibiotictiming did not affect intraoperative culture yield (89% vs. 87%, p=0.531).

However, in patients with a negative preoperative aspiration, withholding prophylaxis significantly increased culture yield (49% vs. 29%, p=0.015).

Conclusion:

Antibiotic prophylaxis timing did not influence overall intraoperative culture yield or aspirate-to-tissue concordance in revision TKA for PJI.

However, when the preoperative aspiration was culture-negative, withholding prophylactic antibiotics significantly improved the likelihood of identifying a pathogen.

Surgeons should consider delaying prophylaxis in this subgroup to optimize microbiologic diagnosis.