Synovial fluid neutrophil extracellular traps could improve the diagnosis of periprosthetic joint infection

Yuanqing Cai; Jialin Liang; Xiaoqing Chen; Guangyang Zhang; Zhaopu Jing; Rupeng Zhang; Leifeng Lv; Wenming Zhang; Xiaoqian Dang

doi:10.1302/2046-3758.122.BJR-2022-0391.R1

Synovial fluid neutrophil extracellular traps could improve the diagnosis of periprosthetic joint infection

Bone Joint Res. 2023 Feb;12(2):113-120. doi: 10.1302/2046-3758.122.BJR-2022-0391.R1.

Authors

Yuanqing Cai^{1

2}, Jialin Liang¹, Xiaoqing Chen³, Guangyang Zhang¹, Zhaopu Jing¹, Rupeng Zhang¹, Leifeng Lv¹, Wenming Zhang², Xiaoqian Dang¹

Affiliations

¹ Department of Orthopaedics, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China.
² Department of Orthopaedics, First Affiliated Hospital, Fujian Medical University, Fuzhou, China.
³ Department of Orthopaedics, Quanzhou First Hospital Affiliated to Fujian Medical University, Quanzhou, China.

PMID: 36718647
PMCID: PMC9950667
DOI: 10.1302/2046-3758.122.BJR-2022-0391.R1

Abstract

Aims: This study aimed to explore the diagnostic value of synovial fluid neutrophil extracellular traps (SF-NETs) in periprosthetic joint infection (PJI) diagnosis, and compare it with that of microbial culture, serum ESR and CRP, synovial white blood cell (WBC) count, and polymorphonuclear neutrophil percentage (PMN%).

Methods: In a single health centre, patients with suspected PJI were enrolled from January 2013 to December 2021. The inclusion criteria were: 1) patients who were suspected to have PJI; 2) patients with complete medical records; and 3) patients from whom sufficient synovial fluid was obtained for microbial culture and NET test. Patients who received revision surgeries due to aseptic failure (AF) were selected as controls. Synovial fluid was collected for microbial culture and SF-WBC, SF-PNM%, and SF-NET detection. The receiver operating characteristic curve (ROC) of synovial NET, WBC, PMN%, and area under the curve (AUC) were obtained; the diagnostic efficacies of these diagnostic indexes were calculated and compared.

Results: The levels of SF-NETs in the PJI group were significantly higher than those of the AF group. The AUC of SF-NET was 0.971 (95% confidence interval (CI) 0.903 to 0.996), the sensitivity was 93.48% (95% CI 82.10% to 98.63%), the specificity was 96.43% (95% CI 81.65% to 99.91%), the accuracy was 94.60% (95% CI 86.73% to 98.50%), the positive predictive value was 97.73%, and the negative predictive value was 90%. Further analysis showed that SF-NET could improve the diagnosis of culture-negative PJI, patients with PJI who received antibiotic treatment preoperatively, and fungal PJI.

Conclusion: SF-NET is a novel and ideal synovial fluid biomarker for PJI diagnosis, which could improve PJI diagnosis greatly.Cite this article: Bone Joint Res 2023;12(2):113-120.

Keywords: CRP; Diagnosis; Mann-Whitney U test; Neutrophil extracellular traps; Periprosthetic joint infection; Periprosthetic joint infection (PJI); Synovial fluid; antibiotics; aseptic failure; biomarkers; revision surgeries; serum; white blood cell.