Perioperative hyponatremia in total joint arthroplasty: A systematic review of prevalence, risk factors, outcomes, and management

Background: Hyponatremia is the most common electrolyte abnormality in hospitalized patients and frequently occurs in the perioperative period of total joint arthroplasty. Although associated with adverse outcomes, its prevalence, predictors, and optimal management strategies in this population remain incompletely defined. This systematic review evaluated the prevalence of perioperative hyponatremia, identified predictors of postoperative hyponatremia, and assessed associated outcomes and management strategies in primary total hip and knee arthroplasty. Methods: PubMed, Google Scholar, and EBSCOhost were searched from January 2000 through December 2023. Studies evaluating prevalence, risk factors, outcomes, or management of perioperative hyponatremia in primary total hip or knee arthroplasty were included. Revision and non-primary procedures were excluded. Twenty studies met inclusion criteria. Risk of bias was evaluated via the Methodological Index for Nonrandomized Studies tool, and the mean score was 19.7 ± 1.4. Due to heterogeneity, results were synthesized qualitatively. Results: Preoperative hyponatremia ranged from 2.1% to 17.8%, whereas postoperative rates ranged from 2.3% to 41.3%, with most cases developing within 24 to 48 h after surgery. Abnormal preoperative sodium was the strongest predictor of postoperative hyponatremia (odds ratios up to 12.33). Preoperative hyponatremia was consistently associated with increased length of stay, readmission, reoperation, periprosthetic fracture, delirium, and medical complications. Limited evidence suggests preoperative sodium optimization may reduce postoperative hyponatremia, whereas correction prior to discharge did not consistently improve outcomes. Conclusion: Perioperative hyponatremia is common in total joint arthroplasty and is associated with worse outcomes, particularly when present preoperatively. Targeted preoperative screening and optimization may improve perioperative risk stratification and outcomes.