Purpose: Preoperative identification of the infecting micro-organism is of paramount importance in the treatment protocol for chronic periprosthetic joint infections, as it enables selection of the most appropriate antibiotic treatment. Preoperative joint aspiration, the most commonly used sampling technique, has proven to have a broad range of sensitivity values and the frequency of dry aspirations has not been well assessed. In such dry-tap cases a biopsy sample could be an option. The purpose of this study was to assess the diagnostic accuracy of percutaneous interface biopsy (PIB) in isolating the infecting organism in cases of chronic Periprosthetic Joint Infection (PJI) and dry-tap event. The basic technique is to harvest and culture a sample from the periprosthetic interface membrane by a percutaneous technique in the preoperative period.
Methods: A retrospective study was done involving 24 consecutive patients suspected of PJI and where no fluid was obtained from the joint. Culture results from a percutaneous interface biopsy (PIB) were compared with intraoperative tissue cultures at the time of revision surgery. In all cases, a two-stage replacement was done.
Results: The sensitivity was 88.2%; specificity was 100%. Positive predictive value was 100%, while negative predictive value was 77.9%. Accuracy was 91.6%. No technique-related complication was observed.
Conclusion: We conclude that PIB is a useful test for preoperative isolation of the infecting organism and could play a role in cases with dry-tap joint aspirations.