The New Blood Tests You Need to Ask About Before Joint Revision

A new study tests whether absolute neutrophil count (ANC) and neutrophil-to-lymphocyte ratio (NLR) can outperform standard markers for diagnosing periprosthetic joint infection (PJI).

Periprosthetic joint infection (PJI) remains one of the most common causes of early revision total joint arthroplasty (TJA), representing 14.8% of total hip arthroplasty (THA) and 25.5% of total knee arthroplasty (TKA) revisions performed in the United States. The risk of PJI after THA and TKA is approximately 0.4%-2% in the United States. Revision takes a great toll on patients, surgeons, healthcare professionals, hospitals, and the healthcare system.

Currently, no single test or scoring method has been shown to be 100% sensitive and specific in diagnosing PJI. While new biomarkers offer potential for increased detection of PJI, they may not be readily available at every institution and can be costly. Therefore, it would be ideal if a synovial marker that is currently utilized in the standard workup of PJI, without requiring additional infrastructure or cost, could be interpreted in a novel way to predict infection.

There has been growing interest in interpreting known biomarkers in a novel way to aid in diagnosing infection, including Absolute Neutrophil Count (ANC) and Neutrophil-to-Lymphocyte Ratio (NLR).