Assessment of Microbiological and Clinical Findings of Two-Stage Revision Arthroplasty Performed Due to Prosthetic Joint Infection.

Background: Two-stage revision arthroplasty remains the main surgical strategy for the treatment of prosthetic joint infections (PJI). Sonicate fluid culture has improved sensitivity compared to standard periprosthetic tissue culture, but its usefulness is questionable during the second stage of revision arthroplasty.

Material and methods: Twenty-seven patients with prosthetic joint infection were investigated. Tissue and sonicate fluid cultures were examined to detect bacteria on the removed spacer during the second stage of exchange arthroplasty. Microbiological findings were analyzed and patients were assessed within an average of 5 years follow up.

Results: Tissue cultures in second-stage revision arthroplasties were positive in 6/27 cases (22.2%) growing CNS in 4 cases (14.8%), Staphylococcus aureus in 1 case (3.7%), and Enterococcus faecalis in 1 case (3.7%). In 3 cases (11.1%) infection was identified as a result of a sonication procedure. Clinical failures at final follow-up were recorded in 4 (14.8%) patients, with reinfection noted in 3 of them. Arthrodesis and spacer exchange followed by suppressive antibiotic therapy were performed in 2 cases.

Conclusions: 1. Tissue cultures remain the gold standard in diagnosis of PIJ although a negative culture does not rule out the presence of bacteria on spacers removed during second stage revision for PJI. 2. Sonication appears to have limited ability to detect persistent infection before reimplantation and was not associated with recurrent infection; however, it can be considered a complementary method that could make it possible to identify new microorganisms and facilitate the selection of appropriate treatment options. 3. The positive results of sonication should be interpreted as the detection of actual pathogens in the light of the clinical, microbiological and histopathological data, especially for patients with immunodeficiency.