Complete Blood Cell Count-Based Ratios Identify Total Joint Arthroplasty Patients Likely to Benefit from Perioperative Dexamethasone

BACKGROUND: Complete blood cell count-based ratios (CBRs), including the neutrophil-lymphocyte ratio (NLR) and monocyte-lymphocyte ratio (MLR), are inflammatory markers associated with postoperative morbidity. Given the link between the surgical stress response and complications after total joint arthroplasty (TJA), this study aimed to evaluate whether higher preoperative CBR values predict greater postoperative benefits associated with dexamethasone utilization. METHODS: The Premier Healthcare Database was queried for adult patients who underwent primary, elective total hip or knee arthroplasty (THA or TKA). Multivariable logistic regression models using dexamethasone exposure and CBRs as independent variables assessed primary end points of 90-day postoperative complications and length of stay (LOS) of ≥3 days. The probability difference between the dexamethasone and non-dexamethasone groups for each primary end point was determined across all values of each CBR. Probability differences were compared across CBR quartiles. RESULTS: A total of 32,849 primary, elective TJAs (12,788 THAs [38.93%], 20,061 TKAs [61.07%]) performed between 2016 and 2021 were identified, and 22,282 (67.83%) of the patients received perioperative dexamethasone. Among patients with an NLR value of >1.00, those receiving dexamethasone had a lower probability of postoperative complications (all p < 0.05). Dexamethasone was associated with lower odds of an LOS of ≥3 days among patients in the highest NLR quartile (≥4.67) compared with the lowest quartile (NLR <1.84) (p = 0.002). Among patients with an MLR value of ≥0.36, those receiving dexamethasone had significantly lower odds of postoperative complications. Dexamethasone was associated with lower odds of an LOS of ≥3 days among patients with an MLR of ≥0.33 (the 2 highest quartiles) compared with an MLR of <0.24 (the lowest quartile) (p = 0.039). CONCLUSIONS: Higher NLR and MLR values were associated with greater marginal benefit from perioperative dexamethasone treatment, establishing a modifiable link between adverse outcomes and perioperative inflammation in TJA. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.