Related Experiment Video
Updated: Dec 24, 2025
Novel Diagnostics in Revision Arthroplasty: Implant Sonication and Multiplex Polymerase Chain Reaction
Published on: December 3, 2017
Improved pre-operative diagnostic accuracy for low-grade prosthetic joint infections using second-generation
Christian Suren1, Susanne Feihl2, Sabrina Cabric3
1Klinik und Poliklinik für Orthopädie und Sportorthopädie, Klinikum rechts der Isar der Technischen Universität München, Ismaninger Str. 22, 81675, Munich, Germany. christian.suren@mri.tum.de.
Background:
A major obstacle for the treatment of prosthetic joint infection (PJI) is the identification of the underlying causative organism. While the diagnostic criteria ruling PJI in or out have become ever more accurate, the detection of the causative pathogen(s) still relies mostly on conventional and time-consuming microbial culture. The aim of this study was to evaluate the diagnostic potential of a second-generation multiplex PCR assay (Unyvero ITI G2, Curetis AG, Holzgerlingen, Germany) used on synovial fluid specimens. Our hypothesis was that the method would yield a higher diagnostic accuracy in the pre-operative workup than synovial fluid culture. Thus, a more precise classification of septic and aseptic prosthesis failure could be achieved before revision surgery.
Methods:
Prospectively collected frozen joint fluid specimens from 26 patients undergoing arthroplasty revision surgery of the hip or knee were tested as per the manufacturer's protocol. Sensitivities, specificities, positive and negative predictive values as well as positive and negative likelihood ratios with corresponding confidence intervals were estimated using the statistical software R. A combination of the serum C-reactive protein (CRP) level, leukocyte count, erythrocyte sedimentation rate, joint fluid culture, tissue biopsy culture, and tissue biopsy histology served as the gold standard.
Results:
Of the 26 patients included in the study, 15 were infected and 11 were aseptic. Conventional joint fluid culture showed a sensitivity of 0.67 and a specificity of 0.91. Joint fluid multiplex PCR yielded a sensitivity of 0.8 and a specificity of 1.0.
Conclusions:
Using the second-generation Unyvero ITI cartridge on joint fluid aspirate for the detection of prosthetic joint infection, we were able to achieve a higher diagnostic accuracy than with conventional culture. We conclude that to improve pathogen detection before revision surgery, this method represents a valuable and practicable tool.
Insights
A new multiplex PCR assay for prosthetic joint infection (PJI) shows higher accuracy than conventional culture. This advanced molecular diagnostic tool improves pathogen detection in synovial fluid before revision surgery.
Area of Science:
- Orthopedics
- Infectious Diseases
- Molecular Diagnostics
Background:
- Accurate identification of causative organisms is critical for treating prosthetic joint infection (PJI).
- Conventional microbial culture for pathogen detection in PJI is time-consuming.
- Improved diagnostic methods are needed for pre-operative classification of septic and aseptic prosthesis failure.
Purpose of the Study:
- To evaluate the diagnostic potential of a second-generation multiplex PCR assay on synovial fluid specimens for PJI.
- To compare the diagnostic accuracy of multiplex PCR with conventional synovial fluid culture.
- To determine if multiplex PCR can enhance pre-operative classification of prosthesis failure.
Main Methods:
- Prospective collection of synovial fluid from 26 patients undergoing hip or knee arthroplasty revision.
- Testing of joint fluid specimens using the Unyvero ITI G2 multiplex PCR assay.
- Statistical analysis of sensitivity, specificity, and predictive values, with a gold standard combining clinical and microbiological data.
Main Results:
- Multiplex PCR demonstrated a sensitivity of 0.8 and a specificity of 1.0.
- Conventional joint fluid culture showed a sensitivity of 0.67 and a specificity of 0.91.
- The study included 15 infected and 11 aseptic cases.
Conclusions:
- The second-generation Unyvero ITI multiplex PCR assay offers higher diagnostic accuracy for PJI detection compared to conventional culture.
- This molecular method is a valuable and practical tool for improving pathogen detection in synovial fluid before revision surgery.
- Enhanced pre-operative diagnosis can lead to more precise classification of septic versus aseptic prosthesis failure.
