Valuation Of Synovial Fluid Calprotectin In The Diagnosis Of Chronic Prosthetic Joint Infection

purposes The aims of this study was to evaluate the diagnostic efficiency of synovial fluid Calprotectin levels in identifying chronic PJI;Compare the sensitivity and specificity of Calprotectin with ESR,CRP,SF-WBC and SF-PMN%;Find the relationship between the synovial fluid Calprotectin and ESR,CRP,SF-WBC and SF-PMN%.Methods Between September 2014 and October 2016,the study included 63 patients with arthroplasty underwent aspiration in our hospital,patients with acute infection were excluded.The Musculoskeletal Infection Society(MSIS)definition of prosthetic joint infection was utilized for classifing cases as aseptic or infected.Sixty-three synovial fluids,including forty-two from patients with an aseptic diagnosis and twenty-one from patients with prosthetic joint infection,met the inclusion criteria of the study.Synovial fluids were tested for Calprotectin levels by enzyme-linked immunosorbent assay(ELISA).We calculated the the area under the curve,sensitivity and specificity of the synovial fluid Calprotectin,and analysedthe expression of Calprotectin between two groups of infection groups,divided based on various characteristics,including antibiotics used,virulence and infection sites.Median CP levels were calculated for each group.The laboratory data of the cases,including ESR,CRP,SF-WBC,SF-PMN% were documented,and each Se and Sp were calculated and compared with the Calprotectin assay by Chi-square test;The correlation between Calprotectin with SF-WBC,PMN%,ESR and CRP was analysed by Pearson correlation coefficient method.Results There were significant difference when performing comparison test between the median CP levels of infection group(776 [IQR,536.5-1132] ?g/ml)and aseptic group(54.5[IQR,38.75-78.25] ?g/ml)(P<0.05).The sensitivity was 95.2% with 97.6% specificity at a threshold of 173ug/ml.The area under the curve was 0.993.Although the infection group included 47.6% patients who received antibiotics before the puncture,the diagnostic efficiency of Calprotectin was not affected.There were no differences in the median CP levels when performing each comparison test among antibiotic administration 663[IQR,480-1106]?g/ml,without antibiotic application 792[IQR,577-1203]?g/ml;virulent organisms(792[IQR,577-1203]?g/ml),less virulentorganisms(780[IQR,417-1203] ?g/ml);hips(763[IQR,417-878] ?g/ml)and knees(929.5[IQR,555.3-1253] ?g/ml).The sensitivity and specificity of ESR?CRP?SF-WBC and SF-PMN% ranged from 76.2% to 90.5% and 64.3% to 85.7%,respectively.The CP assay results outperformed the other tests but did not reach statistical significance(P>0.05),except for the specificity of the ESR and CRP(P<0.05).There was a positive correlation between Calprtotectin with SF-WBC,SF-PMN%,ESR and CRP in patients with PJI,especially SF-PMN%(r = 0.727).Conclusions The Calprotectin of Synovial Fluid with great diagnostic efficiency in the Diagnosis of prosthetic joint infection,which not affected by preoperative antibiotic administration.The synovial fluid Calprotectin assay with high sensitivity and specificity,outperformed the ESR,CRP,SF-WBC and SF-PMN%.There is a positive correlation between the level of Calprotectin and ESR,CRP,SF-WBC and SF-PMN% in patients with PJI.