Neutrophil-to-Lymphocyte Ratio (NLR) and Platelet-to-Lymphocyte Ratio (PLR) Are Potentially Valuable Tests for Diagnosing Periprosthetic Joint Infection

Abstract Background Diagnosis of periprosthetic joint infection (PJI) is challenging for clinicians, and the most commonly used methods are too complicated and expensive for many clinical practices. The neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and platelet–to-mean platelet volume ratio (PVR), are simple biomarkers of infection and can be easily determined from routine blood tests. The aim of our study is to determine the value of these three parameters for the diagnosis of PJI. Methods One hundred and sixty-four patients who received revision surgery after total knee or total hip replacements were enrolled, 47 in a PJI group and 117 in an aseptic failure group. Receiver operator characteristic (ROC) analysis was used to compare the performance of NLR, PLR, PVR, C reactive protein (CRP), and erythrocyte sedimentation rate (ESR) for the diagnosis of PJI. Results The levels of NLR, PLR, and PVR were significantly higher in patients with PJI (all P < 0.05). ROC analysis showed that the area under curve (AUC) values of NLR (0.740), PLR (0.721), and PVR (0.668) were lower than those for CRP (0.896) and ESR (0.829). PLR had the highest sensitivity (85.11%) among all tested biomarkers, and NLR improved the diagnostic performance when used with CRP. Conclusion NLR and PLR are potentially valuable tests for the diagnosis of PJI, but PVR only has limited diagnostic value.