The Influence of Femoral Fixation on Mortality and Revision After Hip Arthroplasty in Femoral Neck Fractures in Patients Older Than 65 Years. A Matched Cohort Analysis From the American Joint Replacement Registry

Introduction: In the United States, most hip arthroplasties for femoral neck fractures are done with a noncemented stem despite worldwide registry data suggesting that cemented fixation has improved long-term survivorship in patients older than 65 years. We, therefore, evaluated the effect of femoral fixation on the risk of revision, revision for periprosthetic fracture (PPFx), and mortality in patients undergoing hip arthroplasty for femoral neck fractures. Methods: Seventeen thousand one hundred thirty-eight cases of cemented femoral stems were exactly matched to noncemented fixation cases in a 1:1 fashion based on age, sex, and Charlson Comorbidity Index as reported in the American Joint Replacement Registry. Outcome variables included revision for PPFx, all-cause revision within 1 year and 90 days, and in-hospital mortality at 90 days and 1 year. The primary independent variable was femoral fixation (cemented and noncemented), and covariates included race (black, white, and others), ethnicity (Hispanic and non-Hispanic), hospital teaching status (minor, major, and nonteaching), and hospital size (number of beds: 1 to 99, 100 to 399, and ≥400). Chi square tests and multivariable logistic regression models were used for statistical analysis. Results: Hip arthroplasty with a cemented stem was associated with a 30% reduction in all-cause revision at 90 days (odds ratio [OR]:0.692, confidence interval [CI]:0.558 to 0.86), a 29% reduction in revision at 1 year (OR:0.709, CI:0.589 to 0.854), and an 86% reduction in revision for PPFx (OR:0.144, CI:0.07 to 0.294). However, cemented stem fixation was associated with increased odds of in-hospital (OR: 2.232 CI: 1.644 to 3.3031), 90-day, and 1-year (OR:1.23, CI:1.135 to 1.339; and OR:1.168, CI:1.091 to 1.25, respectively) mortality. Dicussion: In this exact match study, cemented stem fixation for femoral neck fracture was associated with a markedly reduced risk of revision for PPFx and for all-cause revision. This must be weighed against the associated increased risk in mortality, which warrants additional investigation.