Clinical application of synovial fluid albumin-to-globulin ratio as a novel biomarker in diagnosing chronic periprosthetic joint infection

Background Periprosthetic joint infection (PJI) is one of the most common and severe complications following joint arthroplasty. Early diagnosis is essential for timely and effective clinical intervention and carries great clinical significance. This study aims to evaluate the value of the albumin-to-globulin ratio (AGR) in synovial fluid (SF) for diagnosing PJI and compare its diagnostic performance with traditional biomarkers such as serum C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), synovial fluid polymorphonuclear percentage (SF-PMN%), and the potential marker serum albumin-to-globulin ratio (SE-AGR). Methods This prospective study enrolled 230 patients who experienced pain following total hip or total knee arthroplasty, including 97 cases of PJI and 133 cases of aseptic failure(AF). Blood samples and synovial fluid aspirates were collected within 24 hours preoperatively. The association between each variable and PJI was evaluated using univariate logistic regression analysis, and the diagnostic performance of each indicator was assessed through receiver operating characteristic (ROC) curve analysis. Results The results of the study showed that the Wald χ 2 value of the synovial fluid albumin-to-globulin ratio (SF-AGR) was 47.1, which was higher than that of CRP (43.7) but lower than those of SE-AGR (54.0), ESR (56.5), and SF-PMN% (49.0). Similar to other conventional biomarkers, SF-AGR demonstrated a significant association with PJI. The area under the curve (AUC) of SF-AGR was 0.9504, which was superior to SE-AGR (AUC = 0.8682), ESR (AUC = 0.8427), CRP (AUC = 0.8507), and SF-PMN% (AUC = 0.8843), indicating that SF-AGR showed the most outstanding performance in the preoperative diagnosis of PJI. Conclusion SF-AGR shows promise as a novel biomarker for the diagnosis of PJI, supporting its potential use as an adjunct to current diagnostic approaches. Diagnosis, Periprosthetic Joint Infection, Albumin-to-Globulin Ratio, Synovial Fluid Biomarkers, Revision arthroplasty.