Association between cemented and uncemented cups and risk of revision in patients aged 65 years or older following primary total hip arthroplasty: a study of 310,515 patients from the Nordic Arthroplasty Register Association

BACKGROUND AND PURPOSE: Cemented stem fixation in total hip arthroplasty (THA) reduces early femoral fracture risk in elderly patients, but the optimal method of cup fixation remains controversial. We aimed to compare cup revision risk between cemented and uncemented acetabular cups in patients aged 65 years or older undergoing primary THA. METHODS: This registry-based cohort study used data from the Nordic Arthroplasty Register Association (NARA). We included patients aged 65 years or older who underwent primary THA for primary osteoarthritis or sequelae of childhood hip disorders between 1995 and 2018. The primary outcome was all-cause cup revision, with prespecified analyses stratified by age and sex. Cox regression adjusted for age, sex, femoral head size, time period, and nation was used. Follow-up was divided into 3 periods: 0-1, 1-6, and 6-26 years. RESULTS: Among 310,515 patients, cemented cups were associated with a lower risk of all-cause cup revision during the first year (adjusted hazard ratio [aHR] 0.47, 95% confidence interval [CI] 0.41-0.53) and a higher risk at 6-26 years (aHR 1.91, CI 1.72-2.13). In patients aged 80 years or older, the sex-specific adjusted hazard ratios after the first year were close to 1, with wide confidence intervals. CONCLUSION: Cemented cups were associated with a lower risk of cup revision during the first year across all age groups and a higher risk at 6-26 years in the overall cohort. Among patients aged 80 years or older, we found no evidence of an association between fixation method and cup revision after the first year.