Abstract
Aim
Currently, despite a thorough diagnostic work up, around ten percent of the presumed aseptic revisions turn out to have unexpected positive cultures during the revision procedure. The purpose of this study was to evaluate the negative predictive value (ruling out) of the automated multiplex PCR Unyvero i60 implant and tissue infection (ITI) cartridge (U-ITI) system for the detection of microorganisms in synovial fluid obtained intraoperatively.
Methods
A prospective study was conducted with 200 patients undergoing a one-stage knee or hip revision. In all patients six intraoperative tissue cultures were taken and a sample of synovial fluid which was analyzed as a culture and with the multiplex PCR U-ITI system. The primary outcome measure was the negative predictive value (NPV) of the multiplex PCR U-ITI system compared to the intraoperative tissue cultures to reliable rule out an infection.
Results
The NPV of the multiplex PCR U-ITI system of synovial fluid compared to tissue cultures in knee and hip revisions was 96.8% and 92.5%, respectively. In addition, cultures require several days for growth whereas the automated mPCR U-ITI system provides results within five hours.
Conclusions
The multiplex PCR U-ITI system is a quick additional test to conventional cultures in presumed aseptic knee and hip revisions for reliable ruling out of an underlying infective cause. With this simple test antibiotic overtreatment as well as undertreatment after one-stage revision arthroplasty can be avoided which can directly result in a reduction in length of hospital stay, hospital costs and possible antibiotic resistance development.
