A Comparison of Outcomes of Culture positive and Culture negative Acute Knee Prosthetic Joint Infection following Debridement, Antibiotics and Implant Retention (DAIR)

Purpose We aim to compare the outcome of culture-positive (CP PJI) and culture-negative (CN PJI) acute knee prosthetic joint infection (PJI) following debridement, antibiotics and implant retention (DAIR) with polyethylene insert exchange. We also aim to analyze the factors associated with the successful outcome of DAIR and the influence of failed DAIR on the outcome of subsequent two-stage revision arthroplasty. Methods We performed a retrospective review of 36 consecutive patients who underwent DAIR for acute PJI between January 2013 and January 2018. The patient's demographic data, McPherson grade, surgical details, laboratory and microbiology data were retrieved from the medical records. All the patients have been followed up for a minimum of 3 years or until re-operation, revision or death and any complications, incidence of DAIR failure, revision and mortality were noted. Results The mean follow-up was 4.9 +/- 2.4 years. Among the 36 patients, 16 had CP PJI and 20 had CN PJI. Among the 16 patients with CP PJI, 8 patients had success with DAIR and 8 patients had a recurrence of infection (50%) at a mean of 21 months (range, 2 weeks to 55 months). Among the 20 patients with CN PJI, 14 patients had success with DAIR and 6 patients had a recurrence of infection [30% (6/20)] at a mean of 69 months (range, 13-221 months) (p < .05). The Kaplan-Meir survival analysis showed survivorship did not vary significantly between both groups (p > .05). Univariate regression analysis showed symptom duration of more than one month found to be significantly associated with the DAIR failure. There was no difference in failure rate after DAIR between age, Charlson comorbidity index, early postoperative versus acute hematogenous group and type of organism grown. Ten out of 14 DAIR failures were successfully managed with two-stage revision surgery with no recurrence of infection till the final follow-up. In the remaining 4 patients, one underwent re-debridement, two underwent arthrodesis and one was left with an antibiotic cement spacer. Conclusion DAIR with polyethylene exchange will give comparable results irrespective of the culture positivity. Symptom duration of more than 30 days for DAIR is significantly associated with DAIR failure. DAIR failures can be successfully managed with two-stage revision.