Higher sensitivity of swab polymerase chain reaction compared with tissue cultures for diagnosing periprosthetic joint infection

Purpose: The aim of this study was to assess the diagnostic accuracy of swab polymerase chain reaction (PCR) compared with tissue culture as the current gold standard. Methods: Forty-one consecutive patients were prospectively enrolled undergoing revision arthroplasty due to septic and aseptic reasons. Infection classification was done according to the criteria of the Musculoskeletal Infection Society. Intraoperatively, tissue samples of the periprosthetic membrane were collected for culture analysis, and swabs were taken from the accessible implant surface to perform 16S ribosomal RNA PCR. The diagnostic performance of swab PCR and tissue cultures was determined. Results: Of the 41 patients, 53.7% (n = 22) had a periprosthetic joint infection (PJI) and 46.3% (n = 19) an aseptic loosening. Swab PCR showed a higher sensitivity than tissue cultures (86.4% vs. 68.2%), while the specificity was equal (89.5%). The area under the curve was 0.79 for tissue cultures and 0.88 for swab PCR. Conclusions: In this first investigation of swab PCR for diagnosing PJI, this procedure revealed a higher sensitivity for diagnosing PJI compared with tissue cultures. Because swab PCR is easily implementable and does not require special equipment, it can potentially improve the diagnosis of PJI.