Measurement Of Synovial Fluid Alpha Denfensin-1 In The Diagnosis Of Periprosthetic Joint Infection

Objective The purpose of this study was to evaluate the diagnostic utility of synovial fluid Alpha Denfensin-1 levels in identifying PJI of the arthroplasty.Methods From March 2013 to October,45 patients with arthroplasty underwent aspiration in first-class ternary hospitals in the province of fujian.The Musculoskeletal Infection Society(MSIS) definition of periprosthetic joint infection was utilized for the classification of cases as aseptic or infected.Forty-five synovial fluid aspirates, including twenty-three from patients with an aseptic diagnosis and twenty-two from patients with periprosthetic joint infection, met the inclusion criteria for this prospective study.Synovial fluid aspirates were tested for a-defensin levels with use of enzyme-linked immunosorbent assay(ELISA). We calculated the sensitivity and specificity of the AD-1 synovial fluid assay, and compared it with the sensitivity and specificity of the synovial fluid cell count,Neutrophils%,culture, erythrocyte sedimentation rate, and C-reactive protein. Fluids were recorded and grouped based on various characteristics, including virulence, source joint,systemic inflammatory disease,wound,infection time.Median AD-1 levels were calculated for each group.Comorbidities, such as inflammatory conditions, that could confound a test for periprosthetic joint infection were documented, but the patients with such comorbidities were included in the study.Results Synovial fluid AD-1 tests demonstrated a sensitivity of 86.4% and a specificity of 91.2% for the diagnosis of periprosthetic joint infection.The diagnostic characteristics of these assays were achieved in a population of patients demonstrating a 31.1% rate of systemic inflammatory diseases(in the series as a whole) and a 59% rate of concurrent antibiotic treatment(in the infection group).The synovial fluid levels of AD-1 in the setting of periprosthetic joint infection were unchanged during concurrent antibiotic treatment.There were no differences in the median AD-1 levels when performing each comparison test among virulent organisms(5.46[IQR,2.42-5.98]),less virulent organisms(1.67[IQR,1.15-2.03]);knees(1.68[IQR,1.31-2.04]),hips(2.01[IQR,1.13-4.59]);acute infection(3.59[IQR,1.43-5.86]),chronic infection(1.59[IQR,1.18-2.04]);poor wound healing(0.73 [IQR,0.09-1.42]),good wound healing 0.33( [IQR,0.16-0.45]);Systemic inflammatory disease(0.29[IQR,0.10-0.55]),no Systemic inflammatory disease(0.36[IQR,0.19-0.76])With all each comparisons having a p>0.05.There were also no differences(P=0.165)in the median AD-1 levels when performing comparison test among poor wound healing(0.73[IQR,0.09-1.42]),infection group(1.67[IQR,1.15-2.03]).The sensitivity and specificity of the other tests ranged from 80% to 90.9% and 56.5% to 76%, respectively. The AD-1 assay results outperformed the other tests but did not reach statistical significance(P>0.05)except for the specificity of the Neutrophils%,ESR,C-reactive protein.Conclusions The sensitivity and specificity of the synovial fluid AD-1 assay exceeded the sensitivity and specificity of the other currently available clinical tests.