Postoperative delirium following total joint arthroplasty: epidemiology, risk factors, and associated complications

Introduction: Postoperative delirium (POD) is a feared complication following major surgery in elderly patients. Further investigation of the risk factors and consequences of POD following total joint arthroplasty is warranted. Methods: Patients who underwent total knee arthroplasty (TKA) or total hip arthroplasty (THA) were identified using PearlDiver. Patients were filtered into 2 cohorts based on the presence or absence of POD within 7 days of surgery. Epidemiological analyses were performed to examine trends in POD following TKA and THA by age group and year. Comparative analyses were performed on patient demographics and baseline cognitive status. After matching by age, sex, and comorbidities, electrolyte disturbances and 90-day postoperative complications were analysed. Results: Among 2,518,918 (99.7%) no POD and 7240 (0.3%) POD patients who underwent total knee or hip arthroplasty, mean age was 65.58 years, 60.2% were female, and mean CCI was 1.50 for the whole cohort. POD patients frequently had baseline cognitive impairment ( P < 0.001). Incidence of POD decreased from 0.54% in 2010 to 0.10% in 2022 ( P < 0.001) and increased with age ( P < 0.001). POD patients had higher 90-day costs (TKA = $19,572 vs. $10,397, P < 0.001; THA = $18,496 vs. $9,877 P < 0.001). After matching, POD TKA patients had higher rates of hypernatraemia (6.1% vs 4.5%, P = 0.001) and POD THA patients had higher rates of hyponatraemia (26.5% vs 23.1%, P = 0.008). POD patients had higher rates of 90-day postoperative medical and surgical complications ( P < 0.05) than no POD patients. Conclusions: Nearly 0.3% of patients who underwent either TKA or THA between 2010 and 2022 developed transient delirium. POD was most common in elderly patients with baseline cognitive impairment undergoing revision surgery. POD patients had higher rates of 90-day postoperative surgical and joint-related complications. While POD rates have decreased, continued initiative to prevent POD in total joint arthroplasty patients is imperative.