Synovial Fluid C-reactive Protein as a Diagnostic Marker for Periprosthetic Joint Infection: A Systematic Review and Meta-analysis

Background: Periprosthetic joint infection (PJI) is the main cause of failure following total joint arthroplasty. Until now, the diagnosis of PJI is still confronted with technical limitations, and the question of whether synovial fluid biomarker, C-reactive protein (CRP), can provide high value in the diagnosis of PJI remains unanswered and, therefore, was the aim of the study. Methods: First, we conducted a systematic review on CRP in the diagnosis of PJI by searching online databases using keywords such as "periprosthetic joint infection", "synovial fluid", and "C-reactive protein". Eligible studies providing sufficient data to construct 2 x 2 contingency tables were then selected based on the list of criteria and the quality of included studies was assessed subsequently. Finally, the reported sensitivity, specificity, diagnostic odds ratio (DOR), summary receiver operating characteristic (SROC) curve, and the area under the SROC (AUSROC) were pooled together and used to evaluate overall diagnostic performance. Results: Seven studies were included in our review, six of which comprising a total of 456 participants were further investigated in our meta-analysis. The pooled sensitivity, specificity, and DOR were 0.92 (95% confidence interval [Cl]: 0.86-0.96), 0.90 (95% CI: 0.87-0.93), and 101.40 (95% CI: 48.07-213.93), respectively. The AUSROC was 0.9663 (standard error, 0.0113). Conclusions: Synovial fluid CRP is a good biomarker for the diagnosis of PJI with high sensitivity and specificity.