Majors Isaac, Jagadale Vivek S
Department of Orthopedic Surgery, Central Arkansas Veterans Healthcare System, University of Arkansas College of Medicine, 4300 West 7th St, Little Rock, AR, 72205, USA.
Eur J Orthop Surg Traumatol. 2019 Dec;29(8):1781-1788. doi: 10.1007/s00590-019-02519-y. Epub 2019 Jul 26.
Accurate preoperative diagnosis of prosthetic joint infection (PJI) in the absence of obvious clinical signs or laboratory findings is challenging. Interleukin 6 (IL-6) has been proposed as an infection marker but supportive data are limited. We studied the diagnostic utility of serum IL-6 in infected total knee arthroplasty (TKA).
A prospective cohort study was done in 52 patients (59 knees) with a painful TKA. The abnormal limits for serum IL-6, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), synovial fluid white cell counts (WBC) and synovial fluid neutrophils (PMN) were determined from receiver operating characteristic curves. An infection was defined as the presence of sinus tract or positive culture > two separate tissue or fluid samples. We utilized Mann-Whitney test, Spearman's correlation and Fischer's exact test to determine the sensitivity, specificity, positive predictive value, negative predictive value (NPV) and accuracy of serum IL-6.
The optimal threshold concentration of serum IL-6 was 9.14 pg/ml. Independently, this yielded a sensitivity, specificity and NPV of 81%, 63% and 85%, respectively, and when combined with synovial fluid WBC, values were 100%, 90%, 100%, respectively. The sensitivity and specificity of ESR (70%, 63.6%), CRP (66.7%, 66.7%), synovial WBC (66.7%, 81%) and synovial PMN (82.4%, 73.7%) were also calculated. Serum IL-6 levels strongly correlate with all markers in PJI.
Serum IL-6 improves the diagnosis of PJI over existing methods, especially when combined with synovial fluid WBC. Its optimal usage is as an excellent screening test to rule out infected total knee arthroplasty.
Diagnostic Level II.
在缺乏明显临床症状或实验室检查结果的情况下，准确进行人工关节感染（PJI）的术前诊断具有挑战性。白细胞介素6（IL-6）已被提议作为一种感染标志物，但支持数据有限。我们研究了血清IL-6在感染性全膝关节置换术（TKA）中的诊断效用。
对52例（59膝）有疼痛性TKA的患者进行了一项前瞻性队列研究。通过受试者工作特征曲线确定血清IL-6、C反应蛋白（CRP）、红细胞沉降率（ESR）、滑液白细胞计数（WBC）和滑液中性粒细胞（PMN）的异常界限。感染定义为存在窦道或在两份以上独立组织或液体样本中培养阳性。我们使用曼-惠特尼检验、斯皮尔曼相关性分析和费舍尔精确检验来确定血清IL-6的敏感性、特异性、阳性预测值、阴性预测值（NPV）和准确性。
血清IL-6的最佳阈值浓度为9.14 pg/ml。单独使用时，其敏感性、特异性和NPV分别为81%、63%和85%，与滑液WBC联合使用时，值分别为100%、90%、100%。还计算了ESR（70%，63.
