Neutrophil-Lymphocyte Ratio as A Complementary Biomarker of Periprosthetic Joint Infection: A Retrospective Review

Abstract

Background: Diagnosing a periprosthetic joint infection (PJI) is challenging. No single biomarker can accurately recognize PJI preoperatively in a timely manner. Therefore, the aim of the present study was to investigate the usefulness of the neutrophil-lymphocyte ratio (NLR) in aiding the diagnosis of PJI.Methods: We retrospectively evaluated the medical records of 109 patients who had undergone revision arthroplasty (77 with aseptic mechanic failure and 32 with PJI) from July 2011 to November 2018. Bivariate analysis followed by multivariate logistic regression was applied to compare NLR between two groups. The receiver operating characteristic (ROC) curve was used to assess the diagnostic performance of NLR alone and in combination with C-reactive protein (CRP) and the erythrocyte sedimentation ratio (ESR).Results: NLR was significantly higher in patients with PJI than in patients of the aseptic revision group (3.12 ± 2.45 vs. 2.10 ± 1.03, p < 0.05). ROC curve analysis revealed that NLR had a sensitivity of 56.25% and a specificity of 80.52% with an optimal threshold of 2.52. The diagnostic performance of NLR alone was inferior to that of CRP and ESR as demonstrated by the area under curve, sensitivity, and diagnostic odds ratio. When used in combination with CRP, the diagnostic performance was nearly equal to the combined performance of CRP and ESR or that of all three biomarkers (p > 0.05).Conclusions: NLR is associated with PJI and could be regarded as a complementary marker, which in combination with CRP could improve the diagnostic performance for PJI.