The role of microbiological methods in diagnosis of periprosthetic joint infection in patients with aseptic loosening of total hip arthroplasty

Introduction Instability of the total hip arthroplasty is a common complication and an indication for revision arthroplasty. The implant instability is diagnosed as aseptic with no microbiological culture growth to be obtained through preoperative synovial aspiration. Etiological interpretation of intraoperative findings in cases of so-called "aseptic instability" is critical for determining subsequent treatment strategies. The objective was to determine the role of microbiological methods in diagnosing periprosthetic joint infection (PJI) of the hip. Material and methods A bacteriological analysis was produced for 173 patients with aseptic instability of total hip replacement. The patients aged 27 to 82 years. Based on laboratory, clinical and microbiological (MB) findings, the patients were divided into two groups. The first group consisted of 118 (68.2 %) patients who underwent one-stage revision and had a favorable postoperative prognosis. The second group consisted of 55 (31.8 %) patients with elevated hematological parameters, local signs of inflammation, positive MB findings and had unfavorable prognosis. These patients underwent two-stage revision arthroplasty. Biopsy samples were tested using polymerase chain reaction (PCR) in cases of minimal microbial load. Results Positive MB results were registered in 5.1 % of patients in the first group and in 25.5 % of patients in the second group. Intraoperative biopsies revealed positive results in 20.3 % of the first group and 30.9 % of the second group. PCR identified PJI in 7.5 % of MB biopsies and in 19.6 % of aspirates. Discussion The findings indicated low diagnostic value of microbiological cultures with PCR improving diagnostic accuracy by 7.5 %. Detection of low-virulence microorganisms including coagulase-negative staphylococci required specific evaluation criteria. Conclusion Microbiological culturing demonstrated moderate sensitivity, in low-virulence infections, in particular, while PCR in low-virulence infections was essential in establishing the microbial etiology of PJI.