Synovial Fluid and Serum Neutrophil-to-Lymphocyte Ratio

• DOI: 10.2106/jbjs.21.01279
• Publication Date: 2022-06-21T13:28:54Z
• Authors: Nathan H. Varady; Pierre-Emmanuel S...; Michael M. Kheir; Julian E. Dilley; Hany Bedair; Antonia F. Chen
• Keywords: Adult; Arthritis, Infectious; Prosthesis-Related Infections; Neutrophils; Prognosis; 3. Good health; 03 medical and health sciences; C-Reactive Protein; 0302 clinical medicine; Synovial Fluid; Humans; Lymphocytes; Biomarkers; Retrospective Studies

Background: Septic arthritis (SA) is a musculoskeletal emergency for which prompt diagnosis and treatment are critical. However, traditional diagnostic criteria of synovial fluid (SF) white blood-cell count (WBC) >50,000 cells/mm 3 or >90% polymorphonuclear leukocytes (%PMN) not particularly sensitive specific the SA. Furthermore, prognostic markers lacking. The purposes this study were to assess discriminative ability SF neutrophil-to-lymphocyte ratio (NLR) in SA serum NLR prognosis Methods: A multi-institution, retrospective 598 patients with native shoulder, hip, knee 2000 2018 was conducted. SF-NLR calculated from arthrocentesis cell differential. Receiver operating characteristic curves analyzed, optimal threshold determined using Youden index. Results compared criteria. Similar analyses assessed association 90-day failure mortality subset confirmed hip complete counts differentials (n = 235). (WBC, C-reactive protein [CRP], erythrocyte sedimentation rate [ESR]). Results: (area under receiver curve [AUC], 0.85 [95% confidence interval (CI), 0.82 0.88]) significantly more accurate an than SF-WBC (AUC, 0.80 CI, 0.76 0.83]; p 0.002) SF-%PMN 0.81 0.77 0.84]; 0.01). 25 (78% sensitivity 81% specificity), (56% 80% specificity) (65% 78% specificity). Elevated independently associated (odds [OR], 7.04 3.78 13.14]; < 0.001) (OR, 7.33 2.00 26.92]; 0.003); elevated WBC CRP also failure, WBC, CRP, ESR mortality. Conclusions: This provides compelling data on superior current clinical standards. Given that biomarker requires no additional cost time return laboratory tests already being performed, pending validation, it can readily be used aid clinicians prognostication Level Evidence: Diagnostic IV . See Instructions Authors description levels evidence.