PHILADELPHIA – The addition of sonication did not improve the diagnostic accuracy of clinical cultures of patients with periprosthetic joint infection, according to study results presented at the Musculoskeletal Infection Society Annual Meeting, here.
“Cultures performed in the clinical microbiology lab may be sufficiently sensitive to detect an organism in patients with [periprosthetic joint infection] PJI. But I want to stress that this will vary between centers,” said Angela Hewlett, MD, MS, of the University of Nebraska Medical Center, in Omaha, Neb.
She said sonication has been shown to enhance the yield of standard clinical cultures in patients with PJI, but this has not been validated in the literature.
The prospective study that Hewlett and colleagues conducted compared conventional clinical microbiology lab results to the results obtained after the sonication procedure. In all, the study included 198 patients who underwent revision or resection arthroplasty of the hip and knee, with 60 of the patients fitting the Musculoskeletal Infection Society Work Group criteria for PJI. The explanted prostheses underwent the sonication procedure in addition to routine cultures performed in the clinical microbiology lab. Explanted hip and knee prostheses were placed in sterile polystyrene containers and sterile saline was added. They were then treated with the established sonication protocol and all cultures were done from the fluid samples.
Of the standard cultures performed in the clinical microbiology lab, Hewlett said the sensitivity was 85% with a specificity of 96%. The sensitivity and specificity of sonicated fluid cultures were 78% and 89%, respectively.
The sonication cultures provided an identifiable organism in three patients who had negative tissue cultures from the clinical microbiology lab analysis findings. All of the organisms were Staphylococcus species.
Previous use of antibiotics did not impact the results.
Hewlett said standard cultures identified 83.3% of those patients who fit criteria for PJI while sonication detected 81% of patients with PJI.
“It may be useful to evaluate the sensitivity of the clinical microbiology laboratory before implementing new technology,” she said.
Hartman CW. Sonication for enhanced diagnosis of prosthetic joint infection. Presented at: Musculoskeletal Infection Society Annual Meeting; Aug. 2-3, 2013; Philadelphia.
Disclosure: Hewlett has no relevant financial disclosures.