Mayo Clinic, Rochester, Minnesota, USA.
Mayo Clinic, Phoenix, Arizona, USA.
Bone Joint J. 2021 Jun;103-B(6):1119-1126. doi: 10.1302/0301-620X.103B6.BJJ-2020-1741.R1.
The aim of this study was to determine the diagnostic accuracy of α defensin (AD) lateral flow assay (LFA) and enzyme-linked immunosorbent assay (ELISA) tests for periprosthetic joint infection (PJI) in comparison to conventional synovial white blood cell (WBC) count and polymorphonuclear neutrophil percentage (PMN%) analysis.
Patients undergoing joint aspiration for evaluation of pain after total knee arthroplasty (TKA) or total hip arthroplasty (THA) were considered for inclusion. Synovial fluids from 99 patients (25 THA and 74 TKA) were analyzed by WBC count and PMN% analysis, AD LFA, and AD ELISA. WBC and PMN% cutoffs of ≥ 1,700 cells/mm and ≥ 65% for TKA and ≥ 3,000 cells/mm and ≥ 80% for THA were used, respectively. A panel of three physicians, all with expertise in orthopaedic infections and who were blinded to the results of AD tests, independently reviewed patient data to diagnose subjects as with or without PJI. Consensus PJI classification was used as the reference standard to evaluate test performances. Results were compared using McNemar's test and area under the receiver operating characteristic curve (AUC) analysis.
Expert consensus classified 18 arthroplasies as having failed due to PJI and 81 due to aseptic failure. Using these classifications, the calculated sensitivity and specificity of AD LFA was 83.3% (95% confidence interval (CI) 58.6 to 96.4) and 93.8% (95% CI 86.2 to 98.0), respectively. Sensitivity and specificity of AD ELISA was 83.3% (95% CI 58.6 to 96.4) and 96.3% (95% CI 89.6 to 99.2), respectively. There was no statistically significant difference between sensitivity (p = 1.000) or specificity (p = 0.157) of the two AD assays. AUC for AD LFA was 0.891. In comparison, AUC for synovial WBC count, PMN%, and the combination of the two values was 0.821 (sensitivity p = 1.000, specificity p < 0.001), 0.886 (sensitivity p = 0.317, specificity p = 0.011), and 0.926 (sensitivity p = 0.317, specificity p = 0.317), respectively.
The diagnostic accuracy of synovial AD for PJI diagnosis is comparable and not statistically superior to that of synovial WBC count plus PMN% combined. Cite this article: 2021;103-B(6):1119-1126.
本研究旨在比较α防御素（AD）侧向流动检测（LFA）和酶联免疫吸附测定（ELISA）检测与传统滑膜白细胞（WBC）计数和多形核中性粒细胞百分比（PMN%）分析对人工关节周围感染（PJI）的诊断准确性。
考虑纳入接受关节抽吸以评估全膝关节置换术（TKA）或全髋关节置换术（THA）后疼痛的患者。对 99 例患者（25 例 THA 和 74 例 TKA）的滑膜液进行 WBC 计数和 PMN%分析、AD LFA 和 AD ELISA 检测。TKA 的 WBC 和 PMN%截断值分别为≥1700 个细胞/mm 和≥65%，THA 的截断值分别为≥3000 个细胞/mm 和≥80%。一组三位具有矫形感染专业知识且对 AD 检测结果盲法的医生独立审查患者数据以诊断患者是否存在 PJI。使用共识 PJI 分类作为参考标准来评估测试性能。使用 McNemar 检验和受试者工作特征曲线（ROC）下面积（AUC）分析比较结果。
专家共识将 18 例关节置换术分类为 PJI 失败，81 例为无菌性失败。使用这些分类，AD LFA 的计算灵敏度和特异性分别为 83.3%（95%置信区间[CI]58.6 至 96.4）和 93.8%（95%CI 86.2 至 98.0）。AD ELISA 的灵敏度和特异性分别为 83.3%（95%CI 58.6 至 96.4）和 96.3%（95%CI 89.6 至 99.2）。两种 AD 检测方法的灵敏度（p=1.000）或特异性（p=0.157）均无统计学差异。AD LFA 的 AUC 为 0.891。相比之下，滑膜 WBC 计数、PMN%和两者的组合的 AUC 分别为 0.821（灵敏度 p=1.000，特异性 p<0.001）、0.886（灵敏度 p=0.317，特异性 p=0.011）和 0.926（灵敏度 p=0.317，特异性 p=0.317）。
滑膜 AD 对 PJI 诊断的诊断准确性与滑膜 WBC 计数加 PMN%联合检测相当，且无统计学优势。
