Department of Orthopaedic Surgery, Amphia Hospital, Breda, The Netherlands.
Foundation for Orthopedic Research Care and Education, Amphia Hospital, Breda, The Netherlands.
Arch Orthop Trauma Surg. 2020 Jul;140(7):941-947. doi: 10.1007/s00402-020-03427-1. Epub 2020 Mar 28.
Periprosthetic joint infection (PJI) is one of the most serious complications following total knee arthroplasty (TKA). However, the diagnosis remains a challenge for clinicians. In 2011, the muscoskeletal infection society (MSIS) criteria provided a consensus which has been updated in 2013, but these criteria are complex and contain tests that are time-consuming. The same is applicable to the pro-Implant guidelines. Therefore, a simpler diagnostic test is desirable.
The value of neutrophil gelatinase-associated lipocalin (NGAL), leucocyte esterase (LE) levels, and the white blood cell (WBC) count in synovial fluid to diagnose PJI after TKA was evaluated.
In a retrospective cohort study, we analyzed 89 synovial fluid samples from 86 patients with suspected PJI after TKA. Thirteen and 23 of those samples were classified as PJI according to the MSIS and pro-Implant criteria, respectively. Subsequently, NGAL, LE levels, and the WBC count were determined, the former one using an immunoassay. Using either the MSIS or pro-Implant criteria as the golden standard for PJI, sensitivity and specificity of those markers were determined with ROC curves, and medians were compared with Mann-Whitney U and Pearson Chi-square tests.
When applying the MSIS criteria, NGAL revealed 92% sensitivity and 83% specificity. WBC count showed similar sensitivity (92%) and specificity (84%), whereas sensitivity and specificity for LE were 39% and 88% respectively. When applying the pro-Implant criteria, sensitivity was 95% and specificity was 95% for NGAL. Sensitivity and specificity for WBC count were 100% and 97% and for LE 39% and 92% respectively.
NGAL and WBC count in synovial fluid has high accuracy in the diagnosis of PJI after TKA and should seriously be considered as part of PJI diagnostics. Leucocyte esterase can serve as rule-in criterion peroperatively. These conclusions are independent of which criteria set was used as golden standard.
假体周围关节感染（PJI）是全膝关节置换术（TKA）后最严重的并发症之一。然而，对于临床医生来说，其诊断仍然是一个挑战。2011 年，肌肉骨骼感染协会（MSIS）标准提供了一个共识，该标准在 2013 年进行了更新，但这些标准较为复杂，包含耗时的测试。Pro-Implant 指南也是如此。因此，需要一种更简单的诊断测试。
评估滑液中性粒细胞明胶酶相关脂质运载蛋白（NGAL）、白细胞酯酶（LE）水平和白细胞计数对 TKA 后 PJI 的诊断价值。
在一项回顾性队列研究中，我们分析了 86 例 TKA 后疑似 PJI 患者的 89 份滑液样本。根据 MSIS 和 Pro-Implant 标准，其中 13 份和 23 份样本分别被归类为 PJI。随后，通过免疫测定法测定 NGAL、LE 水平和白细胞计数，前者采用免疫测定法。分别以 MSIS 和 Pro-Implant 标准为 PJI 的金标准，用 ROC 曲线确定这些标志物的灵敏度和特异性，并采用 Mann-Whitney U 和 Pearson Chi-square 检验比较中位数。
应用 MSIS 标准时，NGAL 的灵敏度为 92%，特异性为 83%。白细胞计数的灵敏度（92%）和特异性（84%）相似，而 LE 的灵敏度和特异性分别为 39%和 88%。应用 Pro-Implant 标准时，NGAL 的灵敏度为 95%，特异性为 95%。白细胞计数的灵敏度和特异性分别为 100%和 97%，LE 分别为 39%和 92%。
滑液中的 NGAL 和白细胞计数在 TKA 后 PJI 的诊断中具有较高的准确性，应认真考虑将其作为 PJI 诊断的一部分。白细胞酯酶可作为术中的规则纳入标准。这些结论与用作金标准的标准集无关。
