Association of Preexisting Neurocognitive Impairments and Perioperative Neurocognitive Disorders for Hip Joint Replacement Surgery: A Prospective Cohort Study.

BACKGROUND The association of preexisting neurocognitive impairments with perioperative neurocognitive disorders is not well-established. The objective of this study was to record incidences of perioperative neurocognitive disorders, to record changes in perioperative neurocognition, and to analyze factors of perioperative neurocognitive changes after hip joint replacement surgeries. MATERIAL AND METHODS Patients scheduled for hip joint replacement surgery were included in the test group (n=499) and patients with osteoarthritis but who were not planned for any type of surgeries were included in the control group (n=499). The cognitive tests were evaluated at the time of enrollment and at 1 week, 3 months, 1 year, and 4 years after baseline. Neurocognitive disorders for the individual parameter was defined as more than 2 SD of mean below norms for that parameter. Neurocognitive disorders were defined as a significant worst condition in at least 2 parameters out of all parameters. RESULTS Compared to baseline, after 3 months the numbers of patients with perioperative neurocognitive disorders were increased (55 vs. 81, p=0.021). After 4 years, there was a significant decline in numbers of patients with perioperative neurocognitive disorders in the test group (55 vs. 3, p<0.0001). At the end of the 3-month follow-up period, elderly patients (p=0.002) and patients with preexisting neurocognitive impairments (p=0.005) had a higher incidence of perioperative neurocognitive disorders. CONCLUSIONS Age and preexisting neurocognitive impairments are markers predicting the risk of perioperative neurocognitive disorders.