Change in organism between first- and second-stage revision for periprosthetic joint infection of knee arthroplasty independently associated with increased risk of failure

AimsAchievement of accurate microbiological diagnosis prior to revision is key to reducing the high rates of persistent infection after revision knee surgery. The effect of change in the microorganism between the first-and second- stage revision of total knee arthroplasty for periprosthetic joint infection (PJI) on the success of management is not clear.MethodsA two-centre retrospective cohort study was conducted to review the outcome of patients who have undergone two- stage revision for treatment of knee arthroplasty PJI, focusing spe-cifically on isolated micro-organisms at both the first-and second- stage procedure. Patient demographics, medical, and orthopaedic history data, including postoperative outcomes and subsequent treatment, were obtained from the electronic records and medical notes.ResultsThe study cohort consisted of 84 patients, of whom 59.5% (n = 50) had successful eradica-tion of their infection at a mean follow- up of 4.7 years. For the 34 patients who had recur-rence of infection, 58.8% (n = 20) had a change in isolated organism, compared to 18% (n = 9) in the infection eradication group (p < 0.001). When adjusting for confound, there was no association when the growth on the second stage was the same as the first (odd ratio (OR) 2.50, 95% confidence interval (CI) 0.49 to 12.50; p = 0.269); however, when a different organism was identified at the second stage, this was independently associated with failure of treatment (OR 8.40, 95% CI 2.91 to 24.39; p < 0.001). There were no other significant dif-ferences between the two cohorts with regard to patient demographics or type of organisms isolated.ConclusionChange in the identified microorganism between first-and second- stage revision for PJI was associated with failure of management. Identification of this change in the microorganism prior to commencement of the second stage may help target antibiotic management and could improve the success of surgery in these patients.

Automated summary

The change in microorganism between the first and second stage of knee revision surgery is associated with treatment failure. Identifying this change prior to the second stage may improve the success of surgery.