Is dislocation following total hip arthroplasty caused while suffering from delirium?

The mechanisms and pathologies of dislocation following total hip arthroplasty (THA) in patients with postoperative delirium remain unclear. Therefore, we conducted a retrospective study of 738 patients (738 hips) who underwent unilateral THA for the treatment of hip osteoarthritis. The patients were divided into two groups; with (n = 8) and without postoperative delirium (n = 730). Patients with postoperative delirium had a higher rate of dislocation following THA due to falling from a standing position on hospitalization than those without postoperative delirium (1/8 [12.5%] patients vs. 0/730 [0%] patients, p = 0.011). A power of 80.2% was provided for the rate of dislocation following THA due to falling from a standing position on hospitalization. Postoperative delirium after THA could be a cause of falling from standing position, leading to dislocation following THA during hospitalization. Therefore, postoperative delirium and its associated falls and injuries during hospitalization should be avoided by the elimination of patient's preventable conditions and adjustment of the hospital environments, particularly in patients with the risk factors for postoperative delirium (eg, older age, general anesthesia, medications given [intraoperative opioids and ketamine and postoperative ketamine and benzodiazepines], higher comorbidity burden [diabetes mellitus, renal diseases, depression, anxiety, and psychoses], and blood transfusions). Further investigations with a larger cohort are needed to clarify this issue.