Neutrophil-to-lymphocyte ratio indicative of periprosthetic joint infection after joint replacement: Study

For this purpose, the researchers performed a retrospective review of patients who underwent revision TJA for PJI at a single center between 2005 and 2018 and compared it with an aseptic cohort who underwent aseptic revision TJA. NLR calculation was done from complete blood counts performed at index surgery and at the time of revision surgery. Receiver operating characteristic curves were analyzed, along with specificity, sensitivity, and positive and negative likelihood ratios. Eighty-nine patients were included in each cohort.

The study led to the following findings:

• The mean NLR in patients who underwent revision for PJI was 2.85 (± 1.27) at the time of index surgery and 6.89 (± 6.64) at the time of revision surgery.
• The mean NLR in patients undergoing revision for PJI (6.89) was significantly higher than aseptic revisions (3.17).

In conclusion, in patients who underwent revision surgery for periprosthetic joint infection, the neutrophil to lymphocyte ratio was markedly elevated at the time of revision compared with the time of index surgery.

"Because it is a readily available and cost-effective test, these findings suggest that NLR may be a useful triage test in PJI diagnosis," the researchers wrote.

Reference:

Nairn, Leah MD; Sivaratnam, Surabhi BHSc; Bali, Kamal MBBS, MSc, FRCSC; Wood, Thomas J. MD, MSc, FRCSC. Neutrophil to Lymphocyte Ratio as an Indicator of Periprosthetic Joint Infection: A Retrospective Cohort Study. Journal of the American Academy of Orthopaedic Surgeons 32(6):p 271-278, March 15, 2024. | DOI: 10.5435/JAAOS-D-23-00600