Alpha defensin, leukocyte esterase, C-reactive protein, and leukocyte count in synovial fluid for pre-operative diagnosis of periprosthetic infection

Abstract

Synovial fluid analysis for diagnosis of prosthetic joint infections has gained increasing interest in the recent past when markers more specific for these infections than the serum ones have been identified. Despite the important steps forward, identification of a gold standard has not yet been identified. In this study, usefulness of alpha defensin, leukocyte esterase, C-reactive protein (CRP), and white blood cells (WBCs) in synovial fluids alone and in combination for diagnosis of prosthetic joint infection was evaluated. Synovial fluids from 32 infected and 34 not infected patients were analyzed. Sensitivity, specificity, positive and negative predictive values, diagnostic accuracy, and receiver-operating characteristic (ROC) curves were calculated for each parameter. Moreover, combination of coupled variables was also evaluated by logistic regression analysis. Sensitivity of alpha defensin, CRP, leukocyte count, and leukocyte esterase were 84.4%, 87.5%, 93.7%, and 93.8%, respectively. Specificity was 91.2% for leukocyte counts, 94.1% for alpha defensin, 97.0% for CRP, and 97.1% for leukocyte esterase. Diagnostic accuracy was 89.4% for alpha defensin, 92.4% for WBC counts and CRP, and 95.5% for leukocyte esterase. No statistical differences were observed in area under the curve (AUC) of the ROC curves of alpha defensin, CRP, and leukocyte counts. Logistic regression analysis applied to a model comprising all the variables showed an AUC higher than AUC of coupled variables. In conclusion, results of this study confirm the high sensitivity and specificity of synovial leukocyte esterase for diagnosis of prosthetic joint infection, also suggesting the need to assess a panel of markers to optimize diagnosis of these infections.

Serum D-Dimer in the Diagnosis of Periprosthetic Knee Infection: Where Are We Today?

“…16 Despite all the extraordinary efforts by the orthopaedic community, the diagnosis of PJI remains a challenge. During the last decade, a plethora of markers [17][18][19] have been evaluated for the diagnosis of PJI with recent evidence suggesting that the use of D-dimer might be valuable for that purpose. 7 Currently, the diagnosis of PJI is not based on a single test but on a combined criteria including various synovial fluid and serological tests, clinical evaluation, microbiology, and histopathological analysis.…”

Alpha-defensin lateral flow test does not appear to be useful in predicting shoulder periprosthetic joint infections

“…Both patients had no sinus tract, which has been described as a cause of false-negative ADLF tests [16,19,26,28]. This might be attributed to a lower synovial α-defensin level due to a weaker inflammatory response to these pathogens [26,29]. On the other side, Deirmengian et al reviewed 1937 synovial fluid samples, in which the correlation of α-defensin and positive bacterial cultures had been analyzed.…”

New developments and future challenges in prevention, diagnosis, and treatment of prosthetic joint infection

“…Produced primarily by PMN, α‐defensins are a set of related low molecular weight polypeptides (called antimicrobial peptides) that have antibacterial activity 14 . When used for the diagnosis of PJI in SF, it achieved sensitivity and specificity of over 90% in the hands of multiple investigators 14,69–74 . In addition, a recently introduced lateral flow immunoassay kit, Synovasure, is now recommended for rapid analysis (~20 minutes) in the surgical suite, though it was found to be slightly less sensitive 15,16,74 .…”