Predictors of Uncontrolled Periprosthetic Joint Infection Following Two-Stage Revision Total Knee Arthroplasty: An Extended Cohort Study

Background: Two-stage revision arthroplasty is widely accepted as the reference standard for chronic periprosthetic joint infection (PJI) after total knee arthroplasty (TKA); however, reinfection or persistent infection occurs in a substantial subset of patients. We aimed to identify independent predictors of uncontrolled PJI following two-stage revision using an extended, single-center co-hort. Methods: We retrospectively reviewed 177 knees with PJI after TKA treated with a uniform two-stage revision protocol between September 2011 and February 2022. Patients were classified as controlled (no further infection-related surgery or antimicrobial therapy ≥2 years after reim-plantation) or uncontrolled (persistent infection after the first stage or reinfection after reim-plantation). Demographics, comorbidities, laboratory parameters, perioperative factors, and microbiological characteristics were compared. Multivariate logistic regression was used to identify independent predictors of uncontrolled infection. Results: Among 177 knees, 145 (81.9%) achieved infection control and 32 (18.1%) were classified as uncontrolled. On multivariate analysis, liver cirrhosis (odds ratio [OR] 11.27; 95% confidence interval [CI] 1.004–126.614; p = 0.0496), the presence of a sinus tract at the first infection-control surgery (OR 3.37; 95% CI 1.374–8.254; p = 0.0079), higher erythrocyte sedimentation rate (ESR) prior to reimplantation (OR 1.02 per mm/hr; 95% CI 1.001–1.033; p = 0.0391), and fungal pathogens (OR 9.13; 95% CI 2.073–40.248; p = 0.0035) inde-pendently predicted uncontrolled PJI. Demographic variables and most routine preoperative laboratory markers, including C-reactive protein before the first stage, were not associated with treatment failure. Conclusions: Liver cirrhosis, the presence of a sinus tract, elevated ESR prior to reimplantation, and fungal infection are independent risk factors for uncontrolled PJI after two-stage revision TKA. Preoperative risk stratification incorporating these variables may assist in optimizing reimplantation timing, tailoring antimicrobial strategies, and improving patient counseling.