Perioperative interventions in preventing postoperative delirium following orthopaedic surgery in the elderly: a Bayesian network meta-analysis

Background: Postoperative delirium (POD) is an acute neuropsychiatric syndrome that occurs following surgery, characterized by inattention and broader cognitive deficits. This study aimed to synthesize randomized evidence on perioperative strategies that prevent POD in elderly patients undergoing orthopaedic surgery. Methods: We conducted a Bayesian network meta-analysis of randomised controlled trials (RCTs) retrieved from PubMed, Embase, Web of Science, and Cochrane Library from inception to March 2026. Eligible trials enrolled adults aged 60 years or older undergoing orthopaedic surgery and reported POD incidence with validated assay assessments. Risk ratios (RR) and mean differences with 95% Credible Interval (CrI) were estimated. The risk of bias was assessed using the Cochrane tool, and the certainty of the evidence was evaluated with the GRADE (Grading of Recommendations Assessment, Development, and Evaluation). Results: 79 RCTs comprising 16,012 patients were included. Compared with placebo, dexmedetomidine (RR 0.49, 95% CrI 0.39-0.61) has the most consistent evidence for reducing the risk of POD incidence, while ketamine (RR 0.39, 95% CrI 0.23-0.64), rivastigmine (RR 0.33, 95% CrI 0.16-0.65), olanzapine (RR 0.35, 95% CrI 0.17-0.71), and lidocaine (RR 0.41, 95% CrI 0.21-0.77) showed promising but heterogeneous benefits across current literature. Evidence for analgesic and anaesthetic interventions was limited. Conclusion: Dexmedetomidine offers the most substantial evidence for lowering POD incidence after orthopaedic surgery in elderly; ketamine, rivastigmine, olanzapine, and lidocaine warrant further evaluation. High-quality, low-bias RCTs are needed to verify the effects of specific analgesic or anaesthetic regimens on POD occurrence. Translational potential statement: This network meta-analysis highlights the promising translational potential of dexmedetomidine in preventing POD for elderly orthopaedic patients. Dexmedetomidine emerges as the most reliable option for immediate clinical adoption, while ketamine, rivastigmine, olanzapine, and lidocaine show promise but require confirmatory trials before routine use. The findings set the stage for personalized anaesthetic protocols that minimize POD and its associated morbidity and healthcare costs.