Risk Factors for Treatment Failure in Patients Who Have Knee Periprosthetic Joint Infection Treated With Two-Stage Exchange Arthroplasty as Well as Their Fate.

<bold>Background: </bold>Two-stage exchange arthroplasty is considered the gold standard treatment for chronic periprosthetic joint infection (PJI). However, there is a scarcity of research investigating the major risk factors for infection recurrence and the prognosis after infection recurrence.<bold>Methods: </bold>This study included 203 patients who underwent 2-stage exchange arthroplasty between June 22, 2010 and January 24, 2017. The need of reoperation for infection-related or PJI-related mortality was considered treatment failure. Participant age, gender, body mass index, comorbidities, culture results, length of hospital stay, cause of treatment failure, operative procedure, and fate were analyzed.<bold>Results: </bold>Fifty-three patients experienced treatment failure (26.1%). Mean follow-up was 63 months (range, 26-103). Based on the multivariate analyses, risk factors for treatment failure included men and positive intraoperative culture during reimplantation. Recurrent infection was most commonly caused by Staphylococcus aureus (32.1%, 17/53), and new microorganisms caused recurrent infection in 34 of 53 (64.2%) patients. In 44 patients who had treatment failure, debridement, antibiotic therapy, irrigation, and retention of prosthesis (DAIR) performed within 6 months of reimplantation and at <3 weeks from symptom onset resulted in a significantly higher success rate than the use of other DAIR protocols (P = .031).<bold>Conclusion: </bold>Men and positive intraoperative culture are major risk factors for 2-stage exchange arthroplasty failure in patients who have knee PJI. Recurrent infection in these patients is usually caused by new microorganisms. DAIR within 6 months of reimplantation and at <3 weeks from symptom onset results in good outcomes in these patients. [ABSTRACT FROM AUTHOR]