Long-term Cognitive Trajectory after Total Joint Arthroplasty.

IMPORTANCE Individuals with total joint arthroplasty (TJA) have long-term exposure to metal-containing implants; however, whether long-term exposure to artificial implants is associated with cognitive function is unknown. OBJECTIVE To compare long-term cognitive trajectories in individuals with and without TJA. DESIGN, SETTING, AND PARTICIPANTS This population-based cohort study assessed serial cognitive evaluations of 5550 participants (>= 50 years of age) from the Mayo Clinic Study of Aging between November 1, 2004, and December 31, 2020. EXPOSURES Total joint arthroplasty of the hip or the knee. MAIN OUTCOMES AND MEASURES Linear mixed-effects models were used to compare the annualized rate of change in global and domain-specific cognitive scores in participants with and without TJA, adjusting for age, sex, educational level, apolipoprotein E epsilon 4 carrier status, and cognitive test practice effects. RESULTS A total of 5550 participants (mean [SD] age at baseline, 73.04[10.02] years; 2830 [51.0%] male) were evaluated. A total of 952 participants had undergone at least 1 TJA of the hip (THA, n = 430) or the knee (TKA, n = 626) before or after entry into the cohort. Participants with TJA were older, more likely to be female, and had a higher body mass index than participants without TJA. No difference was observed in the rate of cognitive decline in participants with and without TJA until 80 years of age. A slightly faster cognitive decline at 80 years or older and more than 8 years from surgery was observed (b = -0.03; 95% CI, -0.04 to -0.02). In stratified analyses by surgery type, the faster decline was observed primarily among older participants with TKA (b = -0.04; 95% Cl. -0.06 to -0.02). CONCLUSIONS AND RELEVANCE In this cohort study, long-term cognitive trajectories in individuals with and without TJA were largely similar except for a slightly faster decline among the oldest patients with TKA; however, the magnitude of difference was small and of unknown clinical significance.