Diagnostic Accuracy of the Synovial Fluid α‐Defensin Lateral Flow Test in Periprosthetic Joint Infection: A Meta‐analysis

OBJECTIVES: There is a controversy on the diagnostic reliability and accuracy of synovial fluid α‐defensin in periprosthetic joint infection (PJI). We performed this meta‐analysis to evaluate the diagnostic accuracy of the α‐defensin lateral flow test in PJI. METHODS: PubMed, Embase, and the Cochrane library were systematically searched, and articles (up to January 2020) on the diagnosis of hip and knee PJIs using the α‐defensin Synovasure lateral flow test were included. The diagnostic accuracy of the α‐defensin lateral flow test in PJI was evaluated using meta‐analysis. The pooled sensitivity, specificity, accuracy, positive and negative likelihood ratio, diagnostic odds ratio, and post‐test probabilities were calculated. RESULTS: Seventeen studies including 1443 cases were included. Meta‐analysis showed the pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and a diagnostic odds ratio was 0.83 (95% CI 0.77, 0.88), 0.95 (95% CI 0.93, 0.97), 16.86 (95% CI 11.67, 24.37), 0.17 (95% CI 0.13, 0.24) and 85.30 (95% CI 47.76, 152.35), respectively. The area under the hierarchical summary receiver operating characteristic curve was 0.97 (95% CI 0.95, 0.98). Subgroup analysis also confirmed the high efficiency of α‐defensin Synovasure lateral flow test in diagnosing PJIs, irrespective of ethnicity. Fagan's nomogram analysis there was a high positive post‐test probability of 94% and a low negative post‐test probability of 15%. CONCLUSIONS: We indicated that the α‐defensin lateral flow test had a high accuracy for diagnosing PJI. Large‐scale studies are needed to validate its significance in PJI diagnosis.