Cognitive Impairment and Postoperative Outcomes in Patients Undergoing Primary Total Hip Arthroplasty and Primary Total Knee Arthroplasty: A Systematic Review and Meta-analysis

INTRODUCTION: Total hip arthroplasty (THA) and total knee arthroplasty (TKA) are commonly performed procedures in older adults. Preoperative cognitive impairment, including mild cognitive impairment, dementia, and frailty-related cognitive decline, may adversely affect postoperative recovery and outcomes. However, the magnitude of this association in arthroplasty patients remains incompletely defined. OBJECTIVE: To evaluate the association between preoperative cognitive impairment and postoperative outcomes in older adults undergoing primary THA or TKA. METHODS: A systematic review and meta-analysis was conducted in accordance with PRISMA guidelines. PubMed and Scopus were searched for studies evaluating preoperative cognitive status and postoperative outcomes in patients aged ≥60 years undergoing THA or TKA. Eligible studies assessed cognition using validated tools or clinical diagnoses and reported postoperative neurocognitive or clinical outcomes. A random-effects meta-analysis using the Restricted Maximum Likelihood estimator was performed. Pooled effect estimates were expressed as odds ratios (ORs) with 95% confidence intervals (CIs). FINDINGS: Ten studies involving 10,573 patients were included. Preoperative cognitive impairment was consistently associated with adverse postoperative outcomes, including postoperative delirium, postoperative cognitive dysfunction, long-term cognitive decline, nonhome discharge, and mortality. The pooled analysis demonstrated a significant association between preoperative cognitive impairment and adverse postoperative outcomes (OR 2.38; 95% CI 1.78-2.98; P < 0.001). Although substantial heterogeneity was observed (I² = 76.7%), the direction of effect was consistent across studies. CONCLUSION: Preoperative cognitive impairment more than doubles the risk of adverse postoperative outcomes following THA and TKA. Routine cognitive screening should be incorporated into preoperative assessment to identify high-risk patients and support perioperative brain health strategies aimed at improving surgical outcomes.