Excellent AUC for joint fluid cytology in the detection/exclusion of hip and knee prosthetic joint infection

Abstract

Background and Aim. The aim of this study was to evaluate the characteristics of synovial fluid (SF) white cell count (SWCC) and neutrophil/lymphocyte percentage in the diagnosis of prosthetic joint infection (PJI) for particular threshold values. Methods and Results. This was a prospective study of 391 patients in whom SF specimens were collected before total joint replacement revisions. SF was aspirated before joint capsule incision. The PJI diagnosis was based only on non-SF data. Receiver operating characteristic plots were constructed for the SWCC and differential counts of leukocytes in aspirated fluid. Logistic binomic regression was used to distinguish infected and non-infected cases in the combined data. PJI was diagnosed in 78 patients, and aseptic revision in 313 patients. The areas (AUC) under the curve for the SWCC, the neutrophil and lymphocyte percentages were 0.974, 0.962, and 0.951, respectively. The optimal cut-off for PJI was 3,450 cells/μL, 74.6% neutrophils, and 14.6% lymphocytes. Positive likelihood ratios for the SWCC, neutrophil and lymphocyte percentages were 19.0, 10.4, and 9.5, respectively. Negative likelihood ratios for the SWCC, neutrophil and lymphocyte percentages were 0.06, 0.076, and 0.092, respectively. Conclusions. Based on AUC, the present study identified cut-off values for the SWCC and differential leukocyte count for the diagnosis of PJI. The likelihood ratio for positive/negative SWCCs can significantly change the pre-test probability of PJI.

Gender-related differences observed among immune cells in synovial fluid in knee osteoarthritis

“…The resulting cell pellet was further aliquoted and stained with monoclonal fluorescent antibodies. The microbial culture and synovial white cell count were assessed as reported previously 15 when an appropriate amount of SF was available.…”

Comparative analysis of 23 synovial fluid biomarkers for hip and knee periprosthetic joint infection detection

“…Traditional synovial fluid biomarkers are total leukocyte count and neutrophil percentage, with both exhibiting suitable diagnostic characteristics for PJI, based on previous research 31 . In this study, the former was the most discriminatory biomarker evaluated among the 23 tested, with percent neutrophils being the second most discriminatory, followed by synovial fluid CRP, α‐defensin, and percent monocytes.…”

Combination of albumin-to-globulin ratio and plasma fibrinogen is a sensitive tool for preoperative screening of infected nonunion in patients undergoing reoperation after open reduction and internal fixation: a retrospective study

“…MLR, NLR, and PLR have been demonstrated as stable and cost-effective biomarkers that reflect the inflammatory response as they mediate inflammation by various biochemical mechanisms [ 48 , 49 ]. Previous research suggested that NLR may perform better than CRP for diagnosing early PJI [ 50 ]. In the contrast, most studies showed that MLR, NLR, and PLR showed limited diagnostic value in the preoperative diagnosis of infected nonunion, which was similar to our result [ 11 , 22 ].…”