Total Hip Arthroplasty Is Associated With Lower 90-Day Inpatient Readmission Than Hemiarthroplasty for Femoral Neck Fracture in Patients Aged 65-75 Years: A Propensity Score-Matched Nationwide Readmissions Database Study

Background Comparative early hospital-based outcomes of hemiarthroplasty and total hip arthroplasty (THA) for femoral neck fracture remain uncertain in patients aged 65-75 years. Methods Using the 2022 Nationwide Readmissions Database, we identified patients aged 65-75 years admitted with an acute femoral neck fracture who underwent hemiarthroplasty or THA. Patients were matched 1:1 using exact matching on age, Hospital Frailty Risk Score category, and mental-disorder status, plus propensity-score matching with a 0.20-standard-deviation caliper. The primary outcome was all-cause inpatient readmission within 90 days. Results Among 8,012 eligible admissions, 5,108 patients underwent hemiarthroplasty and 2,904 underwent THA. Matching yielded 2,702 patients per group, with all postmatch absolute standardized mean differences <0.10. THA was associated with a lower observed 90-day inpatient readmission rate than hemiarthroplasty (10.1% vs 15.7%; odds ratio, 0.60; 95% confidence interval, 0.51-0.71; P < .001). Death during the first readmission was also less frequent after THA (0.1% vs 0.7%; P = .002). A narrowly defined inpatient principal-diagnosis dislocation indicator did not differ significantly between groups and should not be interpreted as overall dislocation incidence. Index and total 90-day hospital charges were higher with THA. Conclusions In this observational claims-based study, THA was associated with a lower observed 90-day inpatient readmission rate than hemiarthroplasty. Residual selection bias may partly explain this association, and these findings do not establish a causal benefit of THA. Level of Evidence Level III, Retrospective comparative study.