Department of Reconstructive Surgery of Osteo-articular Infections, IRCCS Istituto Ortopedico Galeazzi, Milan, Italy.
ASST Ovest Milanese, UOC Ortopedia e Traumatologia, Ospedale di Legnano, Milan, Italy.
J Arthroplasty. 2022 Mar;37(3):565-573. doi: 10.1016/j.arth.2021.11.022. Epub 2021 Nov 22.
We evaluated the reliability of intraoperative assessment of leukocyte esterase (LE) in synovial fluid samples from patients undergoing reimplantation following implant removal and spacer insertion for periprosthetic joint infection (PJI). Our hypothesis was that a positive intraoperative LE test would be a better predictor of persistent infection than either serum C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR) or the combination of serum CRP and ESR.
The records of 76 patients who received a 2-stage exchange for PJI were retrospectively reviewed. Synovial fluid was collected for LE measurement during surgery before arthrotomy in 79 procedures. Receiver operating characteristic curves were generated. Sensitivity, specificity, positive predictive value, negative predictive value, accuracy, and area under the curve (AUC) of LE, CRP, ESR, and CRP + ESR were calculated.
Sensitivity, specificity, positive predictive value, and negative predictive value of the LE assay were 82%, 99%, 90%, and 97%, respectively. Receiver operating characteristic analysis revealed an LE threshold of 1.5 between the first (negative) and the second (positive) level of the ordinal variable, so that a grade starting from 1+ was accurate for a diagnosis of persistent infection (AUC 0.9044). The best thresholds for the CRP and the ESR assay were 8.25 mg/L (82% sensitivity, 84% specificity, AUC 0.8416) and 45 mm/h (55% sensitivity, 87% specificity, AUC 0.7493), respectively.
The LE strip test proved a reliable tool to diagnose persistence of infection and outperformed the serum CRP and ESR assays. The strip test provides a valuable intraoperative diagnostic during second-stage revision for PJI.
我们评估了白细胞酯酶（LE）在关节置换术后感染（PJI）患者接受翻修术和间隔器插入术时关节液样本的术中评估的可靠性。我们的假设是，阳性的术中 LE 试验将比血清 C 反应蛋白（CRP）或红细胞沉降率（ESR）或血清 CRP 和 ESR 的组合更能预测持续性感染。
回顾性分析了 76 例接受 2 期关节置换术治疗 PJI 的患者的记录。79 例手术中在关节切开术前采集关节液进行 LE 测量。生成了受试者工作特征曲线。计算了 LE、CRP、ESR 和 CRP+ESR 的敏感性、特异性、阳性预测值、阴性预测值、准确性和曲线下面积（AUC）。
LE 检测的敏感性、特异性、阳性预测值和阴性预测值分别为 82%、99%、90%和 97%。LE 检测的受试者工作特征分析显示，在有序变量的第一（阴性）和第二（阳性）水平之间，LE 阈值为 1.5，因此，1+级别的检测结果准确诊断持续性感染（AUC 0.9044）。CRP 和 ESR 检测的最佳阈值分别为 8.25mg/L（82%敏感性，84%特异性，AUC 0.8416）和 45mm/h（55%敏感性，87%特异性，AUC 0.7493）。
LE 条带试验是一种可靠的工具，可以诊断感染的持续性，优于血清 CRP 和 ESR 检测。在 PJI 的二期翻修术中，条带试验提供了一种有价值的术中诊断方法。
