Delirium following total hip or knee arthroplasty: A retrospective, single-center study

Delirium is a postoperative complication that may occur in older patients. This study aimed to investigate the incidence of postoperative delirium and its risk factors in patients who had undergone total hip arthroplasty (THA) or total knee arthroplasty (TKA). Few reports have addressed the occurrence of delirium when different methods of pain control are used following total joint arthroplasty, and, therefore, whether its incidence varied depending on differences in pain control was investigated.

The study included 500 patients (250 cases of THA and 250 of TKA). They were divided into two groups according to the occurrence of postoperative delirium, and risk factors for delirium (patient factors and operative factors) were investigated. As pain control, all patients were given a Ranawat cocktail injection, with the concomitant use of one of epidural anesthesia, nerve block, or intravenous patient-controlled analgesia (IVPCA), and the occurrence of delirium in patients using each method was investigated.

On univariate analysis, advanced age, low serum albumin, nonbenzodiazepine use, and anti-parkinsonian drug use were identified as patient factors, and low postoperative minimum hemoglobin, non-use of epidural anesthesia, and non-use of nerve block were identified as operative factors associated with a significantly higher incidence of delirium. A receiver-operating characteristic curve was created for age and delirium, and the cutoff age was 77 years. On binomial logistic regression analysis for age ≥77 years, epidural anesthesia, IVPCA, and nerve block, the only factor associated with the occurrence of delirium was age, irrespective of the type of pain relief used, and the odds ratio for the occurrence of delirium at age ≥77 years was 4.64.

To prevent delirium following total joint arthroplasty, it is important to improve anemia and nutritional status, check and manage regular medications, and provide appropriate pain control while avoiding opioid use.