Summary

The time since primary TKA can predict DAIR success in treating prosthetic joint infection.

Abstract

Introduction

There remains a lack of consensus on the optimal indications for performing debridement, antibiotics and implant retention (DAIR) for prosthetic joint infection (PJI) following total knee arthroplasty (TKA). Numerous PJI classification systems have been proposed, but it is unclear if they can be used to predict DAIR success. This study aimed to identify the success rate of DAIR in a large multicenter cohort and compare the success rates of DAIR between different classification systems of PJI.

Methods

Data was analyzed from the Prosthetic joint Infection in Australia and New Zealand Observational (PIANO) study, a multicenter, prospective study of PJIs occurring between July 2014 and December 2017 in 27 hospitals across Australia and New Zealand. First time PJIs occurring after primary TKA that were managed with DAIR were included for analysis. Baseline patient and surgical data were collected on patient enrolment, and follow-up completed at 1- and 2-years. Treatment success was defined as the patient being alive with documented absence of clinical or microbiological evidence of infection and no ongoing use of antibiotics for the index joint at 2-year follow-up. The rate of DAIR success was compared against different types of PJI as defined by four different classification systems including the Coventry system (early PJI <1 month since primary TKA versus 1-24 months and =24 months), the ICM system (early PJI <90 days since primary TKA, late PJI >90 days), the Auckland system (early PJI = <1 year since primary TKA, late PJI = >1 year) and the Tsukayama system (early PJI = <1 month since primary TKA, hematogenous PJI = >1 month with less than 7 days of symptoms, chronic PJI = >1 month with more than 7 days of symptoms). Univariate analysis was performed via Chi-square test. Multivariate binary logistic regression was performed to compute odds ratios (OR) with 95% confidence intervals (CI). Individual multivariate models were produced for each classification system with adjustment for patient age, gender, body mass index, patient comorbidities, number of infecting organisms and the presence of Staphylococcus aureus or gram-negative bacteria.

Results

A total of 189 PJI cases were managed with DAIR, with an overall success rate of 45% (85 out of 189). Early PJIs had a higher rate of DAIR success when analyzed according to the Coventry system (adjusted OR = 3.85, 95% CI 1.41 – 10.50, p = 0.008), the ICM system (adjusted OR = 3.08, 95% CI 1.41 – 6.72, p = 0.005) and the Auckland system (adjusted OR = 2.60, 95% CI 1.26 – 5.35, p = 0.01). A lower rate of DAIR success was observed in both hematogenous (adjusted OR = 0.36, 95% CI 0.14 – 0.93, p = 0.034) and chronic infections (adjusted OR = 0.14, 95% CI 0.04 – 0.51, p = 0.003).

Discussion And Conclusion

The success rate of DAIR is highest when performed in infections occurring within one year of the primary TKA. Late infections had a high failure rate following DAIR irrespective of their classification as hematogenous or chronic. Time since primary is a useful predictor of DAIR success.