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Updated: Dec 12, 2025
Novel Diagnostics in Revision Arthroplasty: Implant Sonication and Multiplex Polymerase Chain Reaction
Published on: December 3, 2017
Microbiological diagnosis of intramedullary nailing infection: comparison of bacterial growth between tissue sampling
Carlos Augusto Finelli1, Cely Barreto da Silva2, Maria Aparecida Murça2
1Universidade Federal de São Paulo, Escola Paulista de Medicina, São Paulo, SP, Brazil.
Background:
Intramedullary nailing (IMN) has been frequently indicated to treat long bone open and closed fractures, but IMN infection (IMNI) may have devastating consequences. Sonication has been regarded as an important add-on for microbial identification on a variety of orthopaedic implant-associated infections, but its role in the IMNI is poorly studied. We aim at evaluating the accuracy obtained by conventional peri-implant tissue culture (TC) samples with sonication fluid cultures (SCs) of IMNI.
Methods:
Longitudinal prospective cohort study ongoing since June 2014, which included patients with indication for IMN removal due to any reason. Clinical diagnosis of INMI was defined according to publication addressing fracture-related infections. Minimal of two samples from TC were cultured. SCs followed the protocol previously published. Statistical analysis was performed using McNemar's test for related proportions.
Results:
We included 54 patients submitted to IMN retrieval, of whom 47 presenting clinical signs of IMNI. Sensitivity for detecting microorganisms using TC and SC was 89.4% (42/47) and 97.6% (40/41), and specificity was 71.4% (5/7) for both TC and SC (p = 1.00). Positive and negative predictive values for TC and SC were 95.5% (42/44), 95.2% (40/42), 50% (5/10), and 83.3% (5/6), respectively. The most frequent organisms isolated in both TC and SC were Staphylococcus aureus, S. epidermidis, and Enterococcus sp. Polymicrobial infection was diagnosed in 14.8% (8/54) and 25% (12/48) by TC and SC, respectively (p = 0.19).
Conclusion:
Sonication fluid and tissue samples presented similar accuracy on the diagnosis of IMNI, but SC was advantageous of detecting polymicrobial infection.
Insights
Sonication fluid cultures (SCs) show similar accuracy to tissue cultures (TCs) for diagnosing intramedullary nailing infections (IMNIs). However, SCs are better at detecting polymicrobial infections, improving diagnosis of these complex orthopedic implant-associated infections.
Area of Science:
- Orthopedic Surgery
- Infectious Diseases
- Microbiology
Background:
- Intramedullary nailing (IMN) is a common treatment for long bone fractures, but intramedullary nailing infection (IMNI) can lead to severe complications.
- Diagnosing IMNI is challenging, and the role of sonication fluid cultures (SCs) alongside conventional tissue cultures (TCs) requires further investigation.
Purpose of the Study:
- To evaluate the diagnostic accuracy of sonication fluid cultures (SCs) compared to conventional tissue cultures (TCs) for intramedullary nailing infections (IMNIs).
- To assess the utility of SCs in identifying polymicrobial infections in IMNI cases.
Main Methods:
- A prospective cohort study included 54 patients undergoing IMN removal.
- Clinical diagnosis of IMNI was based on established fracture-related infection criteria.
- Microbial analysis involved culturing both peri-implant tissue samples (TC) and sonication fluid (SC).
- Statistical analysis used McNemar's test to compare proportions.
Main Results:
- Sensitivity for detecting microorganisms was 89.4% for TC and 97.6% for SC.
- Specificity was 71.4% for both TC and SC.
- Positive and negative predictive values were comparable between TC and SC.
- Sonication fluid cultures detected polymicrobial infections more frequently (25%) than tissue cultures (14.8%).
Conclusions:
- Sonication fluid cultures and tissue cultures demonstrate similar accuracy in diagnosing IMNI.
- SCs offer an advantage in detecting polymicrobial infections, potentially improving the management of complex orthopedic implant-associated infections.
