Sebastian Sujeesh, Mitterer Jennyfer A, Ahmed Youssef, Frank Bernhard J H, Simon Sebastian, Hofstaetter Jochen G
Michael Ogon Laboratory for Orthopedic Research, Orthopedic Hospital Vienna Speising, Vienna, Austria.
Second Department, Orthopedic Hospital Vienna Speising, Vienna, Austria.
Knee Surg Sports Traumatol Arthrosc. 2025 Aug;33(8):2905-2916. doi: 10.1002/ksa.12652. Epub 2025 Mar 18.
This study aimed to establish the optimal cutoff value for synovial absolute polymorphonuclear neutrophil (APMN) count in distinguishing between septic and aseptic hip and knee revision arthroplasties. We also investigated its effectiveness as an indicator in revision arthroplasties with challenging microbiological findings, including (i) aseptic cases with a single unexpected positive intraoperative culture (UPICs), (ii) septic cases with unexpected negative ICs (UNICs) and (iii) infections caused by high- and low-virulent pathogens.
A total of 616 revision arthroplasties (177:hip, 439:knee) included. Using European Bone and Joint Infection Society (EBJIS) criteria, 325 (52.8%) were classified as infection confirmed, 271 (44%) infection unlikely and 20 (3.2%) as infection likely. International Consensus Meeting (ICM) 2018 criteria classified 308 (50%) as infected, 269 (43.7%) not infected, and 39 (6.3%) as inconclusive. Diagnostic accuracy was assessed through receiver operating characteristic curves and area under the curve (AUC).
Optimal APMN count thresholds using EBJIS criteria in hip and knee joints were 783.6 cells/µL (AUC: 0.92) and 549 cells/µL (AUC: 0.91), respectively. With the ICM criteria, its optimal cutoff values remained unchanged, except for the knee, which shifted to 594.2 cells/µL. Comparing UPICs to other aseptic cases showed no significant median APMN count differences when both criteria's applied, potentially ruling out infection suspicion. In septic cases, APMN counts differed between UNICs and culture positives but were statistically significant with EBJIS criteria (Hip:p = 0.01, Knee:p = 0.03) but not with ICM (p = 0.08). Median APMN counts were significantly elevated in high-virulent compared to low-virulent organisms, with similar trends in most of the other markers. Compared to alpha-defensin, APMN count exhibited better AUC, sensitivity and negative predictive value.
The APMN count represents a simple and inexpensive method that may serve as a complementary diagnostic marker in hip and knee revision arthroplasties with challenging microbiological findings.
Level III, retrospective study.
本研究旨在确定滑膜绝对多形核中性粒细胞（APMN）计数在区分感染性与无菌性髋膝关节翻修置换术中的最佳临界值。我们还研究了其在微生物学检查结果具有挑战性的翻修置换术中作为指标的有效性，包括（i）术中单次意外阳性培养（UPICs）的无菌病例，（ii）意外阴性培养（UNICs）的感染性病例，以及（iii）由高毒力和低毒力病原体引起的感染。
共纳入616例翻修置换术（177例髋关节，439例膝关节）。根据欧洲骨与关节感染学会（EBJIS）标准，325例（52.8%）被分类为确诊感染，271例（44%）感染可能性不大，20例（3.2%）感染可能性较大。国际共识会议（ICM）2018标准将308例（50%）分类为感染，269例（43.7%）未感染，39例（6.3%）结果不确定。通过受试者工作特征曲线和曲线下面积（AUC）评估诊断准确性。
根据EBJIS标准，髋关节和膝关节的最佳APMN计数阈值分别为783.6个细胞/微升（AUC：0.92）和549个细胞/微升（AUC：0.91）。采用ICM标准时，除膝关节的最佳临界值变为594.2个细胞/微升外，其余最佳临界值保持不变。在应用两种标准时，将UPICs与其他无菌病例进行比较，APMN计数中位数无显著差异，可能排除感染怀疑。在感染性病例中，UNICs与培养阳性病例的APMN计数存在差异，但根据EBJIS标准有统计学意义（髋关节：p = 0.01，膝关节：p = 0.03），而根据ICM标准则无统计学意义（p = 0.08）。与低毒力微生物相比，高毒力微生物的APMN计数中位数显著升高，大多数其他标志物也有类似趋势。与α-防御素相比，APMN计数表现出更好的AUC、敏感性和阴性预测值。
APMN计数是一种简单且廉价的方法，可作为微生物学检查结果具有挑战性的髋膝关节翻修置换术中的辅助诊断标志物。
III级，回顾性研究。
