The Clinical Application Research Of Serum Inflammation Index And Synovial Fluid Analysis In The Diagnosis Of Periprosthetic Joint Infection In Patients With Rheumatoid Arthritis

Objective: To study and analyze the optimal cut-off values of serum C-reactive protein(CRP),erythrocyte sedimentation rate(ESR),synovial fluid white blood-cell count(WBC)and polymorphonuclear cell percentage(PMN%)in the diagnosis of periprosthetic joint infection(PJI)in patients with rheumatoid arthritis,and to explore their diagnostic value and clinical significance.Methods: This paper employed the retrospective study method to analyze the clinical data of 246 patients with rheumatoid arthritis(RA)and osteoarthritis(OA)who had received artificial knee and hip replacement in the First Affiliated Hospital of Xinjiang Medical University from January2006 to December 2019.In the 246 patients,there are 46 patients of RA-PJI,64 normal follow-up patients of RA,72 patients of OA-PJI and 64 normal follow-up patients of OA.The receiver operating characteristic curve(ROC curve)was used to determine the optimum cut-off values of CPR,ESR,synovial fluid WBC and PMN% for diagnosing the RA-PJI and OA-PJI.Furthermore,The optimal cut-off values of serum and synovial fluid indexes were evaluated for the diagnostic efficacy of RA-PJI by comparing the area under curve(AUC)of each index and applying the results of joint test analysis.Results:In the prediction of PJI,the difference between the AUC of each detection index and AUC=0.5 was statistically significant(P<0.05)in the RA-PJI group,which has diagnostic value.The results of ROC curve analysis showed that the optimal cut-off values of each detection index were as follows: the optimal cut-off value of CRP for diagnosing RA-PJI was 14.4 mg/L,ESR was 39 mm/1 h,synovial fluid WBC was3654/μL,and PMN% was 65.9%.In RA-PJI group,the specificity of synovial fluid WBC was 92.3%,the positive predictive value was 87.8%,and the area under curve was 0.879(95% CI: 0.776,0.982).Due to the high value in the synovial fluid WBC which have better predicting power and lower misdiagnosis rate,the synovial fluid WBC is the best detection indexe for identifying whether the RA patients have periprosthetic joint infection.The joint test analysis can improve the sensibility or specificity.The specificity for jointly diagnosing the RA-PJI in the serial test can reach up to 100%,which have great application value.Conclusion: The optimum cut-off values of CRP,ESR,synovial fluid WBC and PMN% for diagnosing the RA-PJI are all higher than that for diagnosing the OA-PJI.Thus,the different optimum cut-off values for diagnosing the RA-PJI and OA-PJI can be the important auxiliary index in the definitive diagnosis.However,due to the lack of the individual detection index to be the gold standard to diagnose the RA-PJI presently,it is necessary to further combine multiple detection indicators based on defining the diagnostic threshold of the above indicators in the clinical diagnosis to provide reference basis for clinicians to diagnose RA-PJI early and accurately.