Exploring the Value of the Reporter Gene Assay and Flow Cytometry of Synovial Fluid in Total Hip and Knee Arthroplasty as a Diagnostic Tool for Periprosthetic Joint Infection

Joint replacement is a valuable surgical intervention that improves quality of life, provides pain relief, and restores function of patients. However, some patients need revision surgery due to failure of the implant, with periprosthetic joint infection (PJI) remaining a rare but serious complication following total hip (THA) and knee (TKA) arthroplasty. Diagnosing PJI is a major challenge as no diagnostic test with absolute accuracy exists. The diagnosis is based on a combination of clinical findings, laboratory results from peripheral blood and synovial fluid, microbiological culture, histological evaluation of periprosthetic tissue, and intraoperative findings. However, the preoperative diagnosis can be inconclusive and operative criteria are required for the definitive diagnosis. Therefore, novel diagnosing tools for identification of PJI are necessary.

A recent study using a gene reporter assay, identified biomarkers in synovial fluid that define joint states in patients with osteoarthritis.However, no previous studies have investigated cellular signaling in synovial fluid of patients with PJI. With this study we want to explore the potential of a reporter gene assay of synovial fluid in patients with PJI and without PJI of their TKA and THA.

Also, flow cytometry analysis of biological fluids has recently received increased attention as a potentially valuable method in diagnosing infections. For example, the method is already used to analyze urine samples for urinary tract infections. Recently, researchers have now also used this method to screen for the presence of bacteria. The most important limitation of flow cytometry analysis of synovial fluids for bacteria to date is that it is unclear as to which bacteria count value - the cutoff value - represent patients with PJI and which represent patients without PJI. With this study we want to explore the potential of flow cytometry analysis of synovial fluid in categorizing patients with PJI and without PJI.

Our primary objective is to explore the value of synovial fluid analysis using a reporter gene assay and flow cytometry in the detection of a periprosthetic joint infection.