Increasingly severe malnutrition according to the geriatric nutritional risk index is associated with a greater risk of postoperative adverse events

Background: This study investigates the association between the geriatric nutritional risk index (GNRI), a readily available index measuring the risk of malnutrition, and 30-day postoperative complications following revision total knee arthroplasty (rTKA). Methods: The American College of Surgeons National Surgical Quality Improvement Program database was queried for all patients ≥ 65 who underwent rTKA between 2015 and 2021. The study population was divided into three groups based on preoperative GNRI: normal/reference (GNRI > 98), moderate malnutrition (92 ≤ GNRI ≤ 98), and severe malnutrition (GNRI < 92). Multivariate logistic regression analysis was conducted to investigate the association between preoperative GNRI and postoperative complications. Results: Compared to normal nutrition, moderate malnutrition was independently significantly associated with a greater likelihood of experiencing any complication, blood transfusions, surgical site infection (SSI), non-home discharge, readmission, length of stay (LOS) > 2 days, and mortality. Severe malnutrition was independently significantly associated with a greater likelihood of experiencing any complication, septic shock, pneumonia, unplanned reintubation, cardiac arrest or myocardial infarction, stroke, blood transfusions, still on ventilator > 48 h, SSI, wound dehiscence, acute renal failure, non-home discharge, readmission, unplanned reoperation, LOS > 2 days, and mortality. Severe malnutrition was independently significantly associated with a greater number of complications and had a stronger association with complications compared to moderate malnutrition. Conclusion: Malnutrition identified by GNRI has strong predictive value for short-term postoperative complications following rTKA in geriatric patients and may have utility as an adjunctive risk stratification tool for geriatric patients undergoing rTKA.