Simon Sebastian, Frank Bernhard J H, Aichmair Alexander, Dominkus Martin, Mitterer Jennyfer A, Hartmann Susana Gardete, Kasparek Michael, Hofstaetter Jochen G
Michael Ogon Laboratory for Orthopaedic Research, Orthopaedic Hospital Vienna-Speising, Speisinger Straße 109, Vienna, Austria.
II. Department of Orthopaedic Surgery, Orthopaedic Hospital Vienna-Speising, Speisinger Straße 109, Vienna, Austria.
Knee Surg Sports Traumatol Arthrosc. 2023 Apr;31(4):1462-1469. doi: 10.1007/s00167-022-07268-w. Epub 2022 Dec 12.
Unexpected-positive-intraoperative-cultures (UPIC) are common in presumed aseptic revision-total-knee-arthroplasties (rTKA). However, the clinical significance is not entirely clear. In contrast, in some presumably septic rTKA, identification of an underlying pathogen was not possible, so-called unexpected-negative-intraoperative-cultures (UNIC). The purpose of this study was to evaluate the potential use of synovial alpha-defensin (AD) levels in these patients.
Synovial AD levels from 143 rTKAs were evaluated retrospectively from our prospectively maintained institutional periprostetic joint infection (PJI) biobank and database. The 2018-International Consensus Meeting (ICM) criteria was used to define the study groups. Samples from UPICs with a minimum of one positive intraoperative culture (ICM 2- ≥ 6) (n = 20) and UNIC's (ICM ≥ 6) (n = 14) were compared to 34 septic culture-positive samples (ICM ≥ 6) and 75 aseptic culture-negative (ICM 0-1). Moreover, AD-lateral-flow-assay (ADLF) and an enzyme-linked-immunosorbent-assay (ELISA) in detecting the presence of AD in native and centrifuged synovial fluid specimens was performed. Concentration of AD determined by ELISA and ADLF methods, as well as microbiological, and histopathological results, serum and synovial parameters along with demographic factors were analysed.
AD was positive in 31/34 (91.2%) samples from the septic culture-positive group and in 14/14 (100%) samples in the UNIC group. All UPIC samples showed a negative AD result. Positive AD samples were highly associated with culture positive and histopathological results (p < 0.001). No high-virulent microorganisms (0/20) were present in the UPIC group, compared to infected-group (19/34; 55.9%). High virulent microorganisms showed a positive AD result in 89.5% (17/19) of the cases. Methicillin resistant Staphylococcus epidermis (MRSE) infections had significantly higher AD levels than with methicillin susceptible S. epidermdis (MSSE) (p = 0.003). ELISA and ADLF tests were positive with centrifuged (8/8) and native (8/8) synovial fluid.
AD showed a solid diagnostic performance in infected and non-infected revisions, and it provided an additional value in the diagnosis of UPIC and UNIC associated to rTKAs. Pathogen virulence as well as antibiotic resistance pattern may have an effect on AD levels. Centrifugation of synovial fluid had no influence on ADLF results.
在假定无菌的全膝关节置换翻修术（rTKA）中，术中意外培养阳性（UPIC）很常见。然而，其临床意义尚不完全清楚。相比之下，在一些推测为感染性的rTKA中，无法鉴定出潜在病原体，即所谓的术中意外培养阴性（UNIC）。本研究的目的是评估滑膜α-防御素（AD）水平在这些患者中的潜在应用价值。
回顾性评估了来自我们前瞻性维护的机构假体周围关节感染（PJI）生物样本库和数据库中143例rTKA的滑膜AD水平。采用2018年国际共识会议（ICM）标准定义研究组。将至少有一次术中培养阳性的UPIC样本（ICM 2-≥6）（n = 20）和UNIC样本（ICM≥6）（n = 14）与34例培养阳性的感染样本（ICM≥6）和75例无菌培养阴性样本（ICM 0-1）进行比较。此外，还进行了滑膜侧流分析（ADLF）和酶联免疫吸附测定（ELISA）以检测天然和离心后的滑液标本中AD的存在。分析了通过ELISA和ADLF方法测定的AD浓度，以及微生物学、组织病理学结果、血清和滑膜参数以及人口统计学因素。
感染培养阳性组的34个样本中有31个（91.2%）AD呈阳性，UNIC组的14个样本中有14个（100%）AD呈阳性。所有UPIC样本的AD结果均为阴性。AD阳性样本与培养阳性和组织病理学结果高度相关（p < 0.001）。与感染组（19/34；55.9%）相比，UPIC组中不存在高毒力微生物（0/20）。高毒力微生物在89.5%（17/19）的病例中AD结果呈阳性。耐甲氧西林表皮葡萄球菌（MRSE）感染的AD水平显著高于甲氧西林敏感表皮葡萄球菌（MSSE）感染（p = 0.003）。ELISA和ADLF检测在离心后的滑液（8/8）和天然滑液（8/8）中均呈阳性。
AD在感染和未感染的翻修病例中显示出可靠的诊断性能，并且在诊断与rTKA相关的UPIC和UNIC方面具有额外价值。病原体毒力以及抗生素耐药模式可能对AD水平有影响。滑液离心对ADLF结果没有影响。
