Synovial-Based Tests Outperform Serum Markers to Rule Out Infection in Total Joint Arthroplasties

Total knee arthroplasty (TKA) provides successful results in most patients. Periprosthetic joint infection (PJI) accounts for up to 25% of failed TKAs needing revision. In the clinical workup for revision TKA and revision total hip arthroplasty (THA), the differentiation between septic and aseptic failure is important because both surgical and postoperative treatment strategies differ substantially. In clinical practice, consensus in diagnostic strategy for excluding or diagnosing PJI is still lacking.

A literature search by A. Goud et al in EMBASE, MEDLINE, PubMed, and Cochrane was conducted. Studies involving the diagnosis of PJI in patients with failed TKAs and total hip arthroplasties needing revision were identified. Only studies using the Musculoskeletal Infection Society criteria were included. Quality was assessed using MINORS criteria.

Meta-analysis was performed for each diagnostic test identified in the included studies. Pooled estimates of diagnostic accuracy measures were calculated using a bivariate model and plotted in summary receivereoperator characteristic curves. Positive and negative predictive values were calculated in a hypothetical sample of patients with a given disease prevalence.

 Twenty-four studies met the inclusion criteria, describing a total of 2974 patients.

 Quality scores ranged from 13 to 19.

 Meta-analysis could be performed on 7 unique diagnostic tests.

 Highest pooled sensitivity and specificity were demonstrated for alpha-defensin with values of 86% and 96.6%, respectively.

 alpha-defensin and white blood cell count in synovial fluid demonstrate highest negative predictive value values.

Alpha-defensin and WBC in synovial fluid are accurate tests for ruling out PJI in patients who underwent TKA or THA. In particular, these tests are able to confidently rule out PJI in a clinical setting with low to intermediate prevalence. Therefore, in a clinical setting with low to intermediate prevalence of PJI, the authors recommend performing arthrocentesis and joint fluid analysis using a-defensin and/orWBC count before revision TKA or THA surgery for ruling out PJI.

Further reading:

Synovial-Based Tests Outperform Serum Markers to Rule Out Infection in Total Knee Arthroplasty and Total Hip Arthroplasty: A Systematic Review and Meta-Analysis

Annemarie Goud, Don Nützinger, Akke van der Bij, Kevin Jenniskens, Joel Groenewold, Arthur de Gast, Joris E.J. Bekkers,

The Journal of Arthroplasty 37 (2022) 802e808

https://doi.org/10.1016/j.arth.2021.12.020