Management of prosthetic joint infection treated with two-stage exchange: the impact of antimicrobial therapy duration

Background: The optimal duration of parenteral antimicrobial therapy in patients with prosthetic joint infection treated with a two-stage exchange is unknown. Methods: This analysis compares the outcomes between patients treated with 4 weeks and those treated with 6 weeks of parenteral antimicrobial therapy after a two-stage exchange for prosthetic joint infection. The medical records of all patients with total knee arthroplasty or total hip arthroplasty infections treated with a two-stage exchange between 1995 and 1999 at our institution were reviewed. Cox regression models were used to compare treatment failure rates between patients who were treated for 4 weeks and those who were treated for 6 weeks with antimicrobial therapy after adjusting for the propensity to be treated for 6 weeks. Results: Two hundred and eight prosthetic joint infections occurred in 201 patients. Thirty-nine percent and 61% of prosthetic joint infections were treated with 4 weeks or 6 weeks of parenteral antimicrobials, respectively. The 5-year success rate was 84% and 73% in the 4-week and 6-week groups, respectively. After adjusting for the propensity to be treated for 6 weeks, there was no significant differences in the treatment failure rates between those treated with 6 weeks of parenteral antimicrobials and those treated with 4 weeks [hazard ratio (HR)=1.4, 95% confidence interval (CI), 0.7-2.7; P=0.31]. Conclusions: Six weeks of parenteral antimicrobials between stages did not decrease the treatment failure rate in patients with prosthetic joint infections compared with 4 weeks of treatment.