[Value of the prognostic nutritional index in wound healing outcomes in elderly patients undergoing total knee arthroplasty].

INTRODUCTION: malnutrition is a modifiable risk factor that is associated with a higher number of post-surgical complications in total knee arthroplasty (TKA), such as delayed healing, persistent drainage and prosthetic infection. The identification of simple and reliable nutritional parameters is key to optimizing the preoperative preparation of elderly patients, a particularly vulnerable group.

AIM: the objective of this study was to evaluate the usefulness of the nutritional prognostic index (NPI) and other biochemical parameters as predictors of surgical wound-related complications in patients ≥ 75 years of age undergoing primary TKA.

MATERIAL AND METHODS: a single-center retrospective observational cohort study was conducted. Patients ≥ 75 years of age who underwent surgery for TKA between January 2016 and December 2019, with nutritional data available in the 6 months prior to surgery, were included. Biodemographic, biochemical (albumin, fibrinogen, creatinine, lymphocytes), clinical (hospital stay, readmissions) variables were analyzed, and combined indices (albumin/lymphocyte ratio, albumin/fibrinogen ratio, NPI) were calculated. Prolonged hospital stay ( > 7 days) and readmission were considered as indicators of postoperative complications.

RESULTS: of 584 patients operated on, 117 met inclusion criteria (mean age 79.6 years; 71 males, 46 females). There were 8 readmissions (6.8 %). Patients with albumin < 3.5 g/dl and NPI < 40 had significantly longer stayed (p = 0.004 and p < 0.001, respectively). An NPI < 40 was associated with lower albumin, lymphocyte, and albumin/fibrinogen ratio levels, as well as longer duration of hospitalization (12.8 vs. 6.6 days; p = 0.023). In the analysis of readmissions, only albumin (p = 0.018) and NPI (p = 0.018) showed a significant association.

CONCLUSION: preoperative nutritional assessment could be key to identifying and optimizing the nutritional status of these patients, to reduce postoperative complications. NPI and serum albumin are confirmed as simple and useful nutritional markers to predict postoperative complications in elderly patients undergoing TKA. An NPI value < 40 identifies patients at higher risk of wound complications and prolonged hospital stay, reinforcing the need to incorporate routine nutritional assessment in the preoperative period and to propose specific nutritional interventions in this high-risk group.