Contribution of sonication to the microbiology diagnosis of periprosthetic joint infection: Retrospective study of real-world data

PURPOSE: Despite the progress made in the treatment of periprosthetic joint infections, identifying the causative pathogen remains a challenge. Optimal antibiotic therapy requires a confirmed diagnosis, which relies on two positive cultures for the same microorganism. Even though both can produce consistent results, there is little data on the combination of sonication fluid culture (SFC) with standard fluid and tissue cultures for the microbiology diagnosis. We hypothesized that this combination could increase the number of confirmed microbiology diagnoses. METHODS: This was retrospective, descriptive, single-centre study of consecutive patients who underwent a complete change of their hip or knee prosthesis between January 2019 and September 2021 due to a suspected infection. We expected that at least 5% of patients would have the infectious role of a micro-organism confirmed with sonication. The effect of prior antibiotic therapy was analysed on a subset of patients. RESULTS: The analysis involved 223 patients with PJI diagnosis, 73 of whom had received antibiotics. The rate of confirmed microbiology diagnosis confirmed by one single positive sample culture plus SFC was 13.5% [9.6-18.6]. The rate was not significantly different in patients who had received antibiotic therapy (p = 0.960). CONCLUSION: According to our results, sonication could improve the rate of confirmed microbiology diagnosis of a PJI in our study, both in patients who previously received antibiotic therapy and in patients who had not yet been treated. This could make it a useful supplement to periprosthetic sampling in current practice.