Title : Performance of sonication when compared to an enhanced method of Periprosthetic Tissue Processing (PPT) – when should explanted prosthesis be sent for sonication?
Abstract:
Aims: Periprosthetic Joint Infection (PJI) is a serious complication following joint replacement, with an incidence of 1% to 2% nationally. Accurate diagnosis is critical for effective management, especially as the volume of joint replacements are expected to rise. Traditional tissue culturing techniques often lack sensitivity due to biofilm-encased bacteria, while sonication, which disrupts biofilms using ultrasonic waves, has emerged as a promising diagnostic tool. This study compares sonication with an enhanced Periprosthetic Tissue Processing (PPT) method using an advanced tissue culture process.
Methods: A retrospective analysis of 686 tissue samples and 169 sonication samples from patients undergoing revision or resection arthroplasty for suspected PJI (2020–2024) was conducted. Tissue samples were processed using a combination of bead-blaster homogeniser. Statistical analysis of microbiological cultures assessed contamination rates, sensitivity, specificity, Positive Predictive Value (PPV), and Negative Predictive Value (NPV).
Results: Sonication demonstrated higher sensitivity (92.7%) compared to tissue culture (57.3%), but had higher contamination rates, which decreased from 14.3% in 2020 to 6.0% by 2024 as protocols improved. The mean contamination rate for sonication (excluding 2020) was 7.5%, compared to 2.8% for tissue culture. Disease prevalence was 41.42%, optimising sonication’s PPV (89.33%) and NPV (96.81%) in high-suspicion cases. However, predictive values decreased in low-prevalence scenarios, highlighting the importance of clinical context.
Conclusions: In conclusion, sonication offers superior sensitivity for PJI diagnosis, particularly in high-prevalence settings, but has higher contamination rates than tissue cultures processed with the bead blaster homogeniser. Combining both methods should be used to enhance diagnostic accuracy and identify contamination. Surgeons should consider pre-test probability and clinical context, and a multimodal diagnostic approach is recommended to improve accurate microbiological PJI diagnosis and thus patient outcomes.
