Background: Postoperative delirium (POD) is widely reported as a common postoperative complication following total joint arthroplasty (TJA) of the hip and knee in elderly patients, leading to many adverse effects. We sought to investigate predictors of delirium after TJA.

Methods: PubMed, EMBASE, Cochrane Library and Web of Science were searched up to 2020 for studies examining POD following TJA in elderly patients. Pooled odds ratio (OR) and mean difference (MD) of those who experienced delirium compared to those who did not were calculated for each variable. The Newcastle-Ottawa Scale (NOS) was used for the study quality evaluation.

Results: Fifteen studies with 31 potential factors were included. In the primary analysis, 9 factors were associated with POD, comprising advanced age (MD 3.81; 95% confidence interval (CI) 1.80-5.83), dementia (OR 24.85; 95% CI 7.26-85.02), hypertension (OR 2.26; 95% CI 1.31-3.89), diabetes (OR 2.02; 95% CI 1.15-3.55), stroke (OR 14.61; 95% CI 5.26-40.55), psychiatric illness (OR 2.72; 95% CI 1.45-5.08), use of sedative-hypnotics (OR 6.42; 95% CI 2.53-16.27), lower preoperative levels of hemoglobin (MD - 0.56; 95% CI - 0.89-- 0.22), and lower preoperative mini-mental state examination score (MD - 0.40; 95% CI - 0.69-- 0.12). Twelve studies were included in the systematic review, of which 24 factors were additionally correlated with POD using single studies.

Conclusions: Strategies and interventions should be implemented for the elderly patients receiving TJA surgeries with potential predictors identified in this meta-analysis.