Summary: This article focuses on the evaluation and diagnostic investigations of prosthetic joint infection (PJI) in total joint arthroplasty (TJA) failures. Accurate differentiation between septic and aseptic TJA failure is crucial as it guides appropriate treatment selection. Currently, there is no single test for reliable PJI diagnosis, and multiple diagnostic criteria have been proposed. These criteria vary in sensitivity and specificity, which can result in misdiagnosis or overdiagnosis of PJI. Misdiagnosed PJI patients receive inadequate treatment, while overdiagnosing aseptic failures as PJI can lead to unnecessary overtreatment. Patient evaluation involves gathering information through clinical, histological, cytological, and microbiological parameters. Clinical evaluation includes assessing clinical symptoms, sinus tract communication, and purulence around the implant. Histological evaluation relies on the concentration of neutrophils in periprosthetic membrane or capsular tissue. Cytological evaluation involves joint aspiration for analysis of synovial fluid, including leukocyte count and differential determination.
Microbiological diagnosis is based on synovial fluid culture, tissue sample culture, and sonication. Synovial fluid culture has limitations in sensitivity and may require inoculation in blood culture media for improved results. Tissue sample culture is the most important intraoperative diagnostic procedure, while sonication aids in detaching biofilm microorganisms from implant surfaces for culture.
Various other tests, including serologic markers, alpha defensin, leukocyte esterase, DNA-based molecular diagnostics, synovial markers, and nuclear imaging modalities, show promise in PJI diagnostics but require further validation and study.