Fluorescence in Situ Hybridization (FISH) for the Diagnosis of Periprosthetic Joint Infection in Formalin-Fixed Paraffin-Embedded Surgical Tissues

Current Status and Perspectives of Diagnosis and Treatment of Periprosthetic Joint Infection

Periprosthetic joint infection (PJI) is a catastrophic complication following joint replacement surgery, posing significant challenges to orthopedic surgeons. Due to the lack of a definitive diagnostic gold standard, timely treatment initiation is problematic, resulting in substantial economic burdens on patients and society. In this review, we thoroughly analyze the complexities of PJI and emphasize the importance of accurate diagnosis and effective treatment. The article specifically focuses on the advancements in diagnostic techniques, ranging from traditional pathogen culture to advanced molecular diagnostics, and discusses their role in enhancing diagnostic accuracy. Additionally, we review the latest surgical management strategies, including everything from debridement to revision surgeries. Our summary aims to provide practical information for the diagnosis and treatment of PJI and encourages further research to improve diagnostic accuracy and treatment outcomes.

Emerging Issues and Initial Insights into Bacterial Biofilms: From Orthopedic Infection to Metabolomics

Bacterial biofilms, enigmatic communities of microorganisms enclosed in an extracellular matrix, still represent an open challenge in many clinical contexts, including orthopedics, where biofilm-associated bone and joint infections remain the main cause of implant failure. This study explores the scenario of biofilm infections, with a focus on those related to orthopedic implants, highlighting recently emerged substantial aspects of the pathogenesis and their potential repercussions on the clinic, as well as the progress and gaps that still exist in the diagnostics and management of these infections. The classic mechanisms through which biofilms form and the more recently proposed new ones are depicted. The ways in which bacteria hide, become impenetrable to antibiotics, and evade the immune defenses, creating reservoirs of bacteria difficult to detect and reach, are delineated, such as bacterial dormancy within biofilms, entry into host cells, and penetration into bone canaliculi. New findings on biofilm formation with host components are presented. The article also delves into the emerging and critical concept of immunometabolism, a key function of immune cells that biofilm interferes with. The growing potential of biofilm metabolomics in the diagnosis and therapy of biofilm infections is highlighted, referring to the latest research.

Detection of inguinal lymph nodes is promising for the diagnosis of periprosthetic joint infection

Background

Localized inguinal lymphadenopathy often represents lower extremity pathogen infection, while normalized lymphadenopathy is associated with infection regression. We hypothesized that inguinal lymph nodes (LNs) were enlarged in Periprosthetic Joint Infection (PJI) patients and that normalized inguinal LNs would be a promising way to determine the timing of reimplantation.

Methods

We prospectively enrolled 176 patients undergoing primary and revision hip or knee arthroplasty. All patients underwent ultrasound examination of inguinal LNs preoperatively. The diagnostic value of inguinal LNs in PJI was evaluated by the receiver operating characteristic (ROC) curve.

Results

The median level of inguinal LNs was 26mm in the revision for PJI group compared with 12 mm in the aseptic revision group (p< 0.0001). The size of the inguinal LNs well distinguishes PJI from aseptic failure (AUC= 0.978) compare with ESR (AUC= 0.707) and CRP (AUC= 0.760). A size of 19mm was determined as the optimal threshold value of the inguinal LNs for the diagnosis of PJI, with a sensitivity of 92% and specificity of 96%.

Conclusion

Ultrasonic analysis of inguinal LNs is a valuable piece of evidence for the diagnosis of PJI and evaluation of persistent infection.

Sampling challenges in diagnosis of chronic bacterial infections

In recent decades there has been an increase in knowledge of the distribution, species diversity and growth patterns of bacteria in human chronic infections. This has challenged standard diagnostic methods, which have undergone a development to both increase the accuracy of testing as well as to decrease the occurrence of contamination. In particular, the introduction of new technologies based on molecular techniques into the clinical diagnostic process has increased detection and identification of infectious pathogens. Sampling is the first step in the diagnostic process, making it crucial for obtaining a successful outcome. However, sampling methods have not developed at the same speed as molecular identification. The heterogeneous distribution and potentially small number of pathogenic bacterial cells in chronic infected tissue makes sampling a complicated task, and samples must be collected judiciously and handled with care. Clinical sampling is a step in the diagnostic process that may benefit from innovative methods based on current knowledge of bacteria present in chronic infections. In the present review, we describe and discuss different aspects that complicate sampling of chronic infections. The purpose is to survey representative scientific work investigating the presence and distribution of bacteria in chronic infections in relation to various clinical sampling methods.

Current Clinical Methods for Detection of Peri-Prosthetic Joint Infection

Background: Currently, one of the most pressing problems in the field of orthopedic surgery is peri-prosthetic joint infection [PJI]. While there are numerous ways to detect PJI, current clinical detection methods differ across institutions and have varying criteria and protocols. Some of these methods include the Modified Musculoskeletal Infection Society system, culturing, polymerase chain reaction, the determination of the presence of certain biomarkers, testing for the presence of alpha defensin peptides, and leukocyte level testing. Methods: This review summarizes the most recent publications in the field of PJI detection to highlight current strengths as well as provide future directions to find the system for the quickest, cost-effective, and most accurate way to diagnose these types of infections. Results: The results of this literature review suggest that, while each method of diagnosis has its advantages, each has various drawbacks as well. Current methods can be expensive, take days to weeks to complete, be prone to contamination, and can produce ambiguous results. Conclusions: The findings in this review emphasize the need for a more comprehensive and accurate system for diagnosing PJI. In addition, the specific comparison of advantages and drawbacks can be useful for researchers and clinicians with goals of creating new diagnostic tests for PJIs, as well as in clinical scenarios to determine the correct treatment for patients.