Svoboda M, Gallo J, Zapletalová J, Prošková J, Juráňová J, Lovečková Y
Ortopedická klinika Fakultní nemocnice Olomouc a Lékařské fakulty Univerzity Palackého v Olomouci.
Ústav lékařské biofyziky Lékařské fakulty Univerzity Palackého v Olomouci.
Acta Chir Orthop Traumatol Cech. 2022;89(1):16-26.
PURPOSE OF THE STUDY Laboratory methods are central to prosthetic joint infection (PJI) diagnosis. Most research teams focus on detection of specific inflammatory markers, causative pathogens, or on assessment of the tissue response. This study sought to determine the optimal cut-off values and diagnostic performance of selected synovial markers in relation to the diagnosis of hip or knee PJI. The studied markers were synovial level of glucose, lactate, coefficient of energy balance (CEB) and NGAL (neutrophil gelatinase-associated lipocalin). MATERIAL AND METHODS This prospective study includes 89 patients who underwent revision total knee or hip arthroplasty for septic or aseptic reasons in the period from 2014 to 2017. Among these 89 patients, there are 2 cases of prosthetic hip infection, 22 cases of prosthetic knee infection, 31 aseptic revision total hip arthroplasties and 34 aseptic revision total knee arthroplasties. The diagnostic characteristics of the studied methods were set in relation to the reference standard, the 2013 MSIS (Musculoskeletal Infection Society) criteria. The cut-off values were calculated using the ROC (receiver operating characteristic curve) analysis. RESULTS The synovial glucose test is considered positive if the glucose level drops below 2.65 mmol/L. The area under the curve is 0.813, sensitivity 75.0%, specificity 83.1%. The synovial lactate test is considered positive if lactate level rises above 8.87 mmol/L. The area under the curve is 0.882, sensitivity 70.8%, specificity 95.4%. Synovial NGAL is considered positive if its level exceeds 998 μg/L. The area under the curve is 1.000, sensitivity 100.0%, specificity 100.0%. CEB is considered positive if its value is lower than +4.665. The area under the curve is 0.883, sensitivity 91.7% and specificity 69.8%. Combining of these tests with other synovial markers does not improve the diagnostic performance of the studied tests. CONCLUSIONS The glucose and lactate levels and CEB undoubtedly reflect the presence of an inflammatory process in a prosthetic joint. However, the diagnostic characteristics of these tests are not better than those of other modern diagnostic techniques. As opposed to these tests, synovial NGAL shows excellent diagnostic performance. Nonetheless, the potential of this method shall be verified on larger cohorts of patients. Key words: prosthetic joint infection, periprosthetic infection, total knee arthroplasty, total hip arthroplasty, diagnosis, glucose, lactate, CEB, NGAL.
研究目的 实验室方法是人工关节感染（PJI）诊断的核心。大多数研究团队专注于特定炎症标志物、致病病原体的检测，或组织反应的评估。本研究旨在确定所选滑膜标志物相对于髋或膝PJI诊断的最佳临界值和诊断性能。所研究的标志物为滑膜葡萄糖水平、乳酸水平、能量平衡系数（CEB）和中性粒细胞明胶酶相关脂质运载蛋白（NGAL）。
材料与方法 这项前瞻性研究纳入了89例在2014年至2017年期间因感染性或无菌性原因接受全膝关节或全髋关节翻修术的患者。在这89例患者中，有2例人工髋关节感染、22例人工膝关节感染、31例无菌性全髋关节翻修术和34例无菌性全膝关节翻修术。所研究方法的诊断特征是相对于参考标准——2013年肌肉骨骼感染学会（MSIS）标准确定的。临界值通过ROC（受试者工作特征曲线）分析计算得出。
结果 如果葡萄糖水平降至2.65 mmol/L以下，滑膜葡萄糖检测被认为呈阳性。曲线下面积为0.813，灵敏度为75.0%，特异性为83.1%。如果乳酸水平升至8.87 mmol/L以上，滑膜乳酸检测被认为呈阳性。曲线下面积为0.882，灵敏度为70.8%，特异性为95.4%。如果滑膜NGAL水平超过998 μg/L，则被认为呈阳性。曲线下面积为1.000，灵敏度为100.0%，特异性为100.0%。如果CEB值低于 +4.665，则被认为呈阳性。曲线下面积为0.883，灵敏度为91.7%，特异性为69.8%。将这些检测与其他滑膜标志物联合使用并不能提高所研究检测的诊断性能。
结论 葡萄糖和乳酸水平以及CEB无疑反映了人工关节中炎症过程的存在。然而，这些检测的诊断特征并不优于其他现代诊断技术。与这些检测相反，滑膜NGAL显示出优异的诊断性能。尽管如此，该方法的潜力仍需在更大规模的患者队列中进行验证。
人工关节感染；假体周围感染；全膝关节置换术；全髋关节置换术；诊断；葡萄糖；乳酸；CEB；NGAL
