Different Biomarker Ratios in Peripheral Blood have Limited Value in Diagnosing Periprosthetic Joint Infection after Artificial Joint Replacement：A Single-Center, Retrospective Study
Authors: Deng Lei , Wang Jie , Yang Guang-ya , Hou Ying-zhou , Li Ke-wei , Sun Bo , Wang Shao-hua 
Published: January 2024

Abstract
Background: Periprosthetic joint infection (PJI) is a severe complication that can occur after artificial joint replacement (AJR). The timely and accurate diagnosis of PJI is the key to treatment. This study investigated the diagnostic value of platelet to lymphocyte ratio (PLR), platelet count to mean platelet volume ratio (PVR), neutrophil to lymphocyte ratio (NLR) and monocyte to lymphocyte ratio (MLR) in PJI after total knee arthroplasty (TKA) and total hip arthroplasty (THA).
Methods: Our team conducted a retrospective analysis of 187 patients who received knee or hip joint revision surgeries at the Department of Joint Surgery of Zhengzhou Orthopaedic Hospital between June 2015 and June 2020. The 168 patients were eventually included based on the inclusion and exclusion criteria. According to the diagnostic criteria of the Musculoskeletal Infection Society (MSIS), 58 patients were in the PJI group, and 110 patients were in the aseptic loosening (AL) group. We recorded and compared the preoperative peripheral blood white blood cell (WBC) count, platelet count (PLT), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), PLR, PVR, NLR, and MLR in both groups. The diagnostic performance of the PLR, PVR, NLR, and MLR individually and in combination with the ESR and CRP for PJI diagnosis was evaluated by receiver operating characteristic (ROC) curves, and the sensitivity, specificity, positive predictive value, and negative predictive value were calculated.
Results: Compared to those in the AL group, the mean WBC, PLT, ESR, CRP, PLR, PVR, NLR, and MLR in the peripheral blood of the PJI group were significantly greater (P < 0.05). The analysis of the ROC curve revealed that the ESR, CRP, PLR, PVR, NLR, and MLR in peripheral blood had moderate effectiveness in diagnosing PJI, with area under the curve (AUC) values of 0.760 (95% CI: 0.688-0.823), 0.758 (95% CI: 0.687-0.821), 0.714 (95% CI: 0.639-0.781), 0.709 (95% CI: 0.634-0.777), 0.723 (95% CI: 0.649-0.789), and 0.728 (95% CI: 0.654-0.793), respectively. Conversely, the WBC and PLT counts demonstrated poor diagnostic value for PJI, with AUC values of 0.578 (95% CI: 0.499-0.653) and 0.694 (95% CI: 0.619-0.763), respectively. The results of the prediction model calculations revealed that the combined AUC of the ESR, CRP, PLR, PVR, NLR, and MLR was the highest at 0.841 (95% CI, 0.77-0.893), indicating good value in the diagnosis of PJI, with a sensitivity of 81.0% and a specificity of 72.7%. Moreover, the novel composite of parameters improved the accuracy and reliability in diagnosing PJI compared to the traditional biomarkers ESR and CRP (P < 0.05).
Conclusion: Our study suggested that the diagnostic value of the peripheral blood biomarkers PLR, PVR, NLR, and MLR for diagnosing PJI is limited and not superior to that of the ESR or CRP. However, when the ESR, CRP, PLR, PVR, NLR, and MLR are combined, the diagnostic performance of PJI in AJR patients can be improved.