Outcome and predictors of treatment failure in total hip/knee prosthetic joint infections due to Staphylococcus aureus

Abstract

Background: Variables associated with the outcome of patients treated for prosthetic joint infections (PJIs) due to Staphylococcus aureus are not well known.

Methods: The medical records of patients treated surgically for total hip or knee prosthesis infection due to S. aureus were reviewed. Remission was defined by the absence of local or systemic signs of implant-related infection assessed during the most recent contact with the patient.

Results: After a mean posttreatment follow-up period of 43.6 ± 32.1 months, 77 (78.6%) of 98 patients were in remission. Retention of the infected implants was not associated with a worse outcome than was their removal. Methicillin-resistant S. aureus (MRSA)-related PJIs were not associated with worse outcome, compared with methicillin-susceptible S. aureus (MSSA)-related PJIs. Pathogens identified during revision for failure exhibited no acquired resistance to antibiotics used as definitive therapy, in particular rifampin. In univariate analysis, parameters that differed between patients whose treatment did or did not fail were: American Society of Anesthesiologists (ASA) score, prescription of adequate empirical postsurgical antibiotic therapy, and use of rifampin combination therapy upon discharge from hospital. In multivariate analysis, ASA score ≤2 (odds ratio [OR], 6.87 [95% confidence interval {CI}, 1.45-32.45]; P = .04) and rifampin-fluoroquinolone combination therapy (OR, 0.40 [95% CI, 0.17-0.97]; P = .01) were 2 independent variables associated with remission.

Conclusions: The results of the present study suggest that the ASA score significantly affects the outcome of patients treated for total hip and knee prosthetic infections due to MSSA or MRSA and that rifampin combination therapy is associated with a better outcome for these patients when compared with other antibiotic regimens.

Figure 1.

Kaplan–Meier estimates of the cumulative risk of failure according to the treatment group assessed at 24 months follow-up. Patients in the rifampin-fluoroquinolone treatment group had a lower risk of experiencing treatment failure than did patients treated with other antibiotic regimens (P = .003). Dotted line, rifampin-fluoroquinolone treatment group (n = 39); solid line, other regimens group (n = 59).