Alpha-defensin and the Synovasure lateral flow device for the diagnosis of prosthetic joint infection: a systematic review and meta-analysis

AimsThe aim of this review is to evaluate the available literature and to calculate a pooled diagnostic sensitivity and specificity for the different alpha-defensin test systems to diagnose peri-prosthetic infection.Materials and MethodsStudies using alpha-defensin or Synovasure to diagnose periprosthetic joint infection were identified from systematic searches of electronic databases. Study quality was evaluated using the QUADAS tool. Meta-analysis was completed using a bivariate model.ResultsEleven eligible studies were included. Median QUADAS score was 13 [I.Q.R. 13-13] out of 14. Significant conflicts of interest were identified in five studies. Pooled sensitivity for the laboratory alpha-defensin test was 0.95 (95% CI 0.91-0.98) and specificity 0.97 (95% CI 0.95-0.98) for four studies with a threshold level of 5.2mgl-a. Pooled sensitivity for the lateral flow cassette test was 0.85 (95% CI 0.74-0.92) and specificity was 0.90 (95% CI 0.91-0.98). There was a statistically significant difference in sensitivity but not specificity.ConclusionLaboratory based alpha-defensin testing remains a promising tool for diagnosing periprosthetic joint infection. The lateral flow cassette has a significantly lower performance and pooled results are comparable to the leucocyte esterase test. Further studies are essential before the widespread adoption of the lateral flow cassette alpha-defensin test. Take home messageAlpha defensin testing for periprosthetic joint infection has excellent sensitivity and specificity when performed in a laboratory. The pooled sensitivity and specificity is much lower when results are combined for the lateral flow cassette (Synovasure devise