Unipolar Hemiarthroplasty, Bipolar Hemiarthroplasty, or Total Hip Arthroplasty for Hip Fracture in Older Individuals

Background: Practice patterns regarding the use of unipolar hemiarthroplasty, bipolar hemiarthroplasty, and total hip arthroplasty (THA) for femoral neck fractures in older patients vary widely. This is due in part to limited data stipulating the specific circumstances under which each form of arthroplasty provides the most predictable outcome. The purpose of this study was to investigate the patient characteristics for which unipolar hemiarthroplasty, bipolar hemiarthroplasty, or THA might be preferable due to a lower risk of all-cause revision. Methods: A U.S. health-care system’s hip fracture registry was used to identify patients ≥60 years old who underwent unipolar hemiarthroplasty, bipolar hemiarthroplasty, or THA for hip fracture from 2009 through 2021. Unipolar and bipolar hemiarthroplasty were compared with THA within patient subgroups defined by age (60 to 79 versus ≥80 years) and American Society of Anesthesiologists (ASA) classification (I or II versus III); patients with an ASA classification of IV or higher were excluded. Multivariable Cox proportional hazard regression analysis was used to evaluate all-cause revision risk while adjusting for confounders, with mortality considered as a competing risk. Results: There were 14,277 patients in the final sample (median age, 82 years; 70% female; 80% White; 69% with an ASA classification of III; median follow-up, 2.7 years), and the procedures included 7,587 unipolar hemiarthroplasties, 5,479 bipolar hemiarthroplasties, and 1,211 THAs. In the multivariable analysis of all patients, both unipolar (hazard ratio [HR] = 2.15, 95% confidence interval [CI] = 1.48 to 3.12; p < 0.001) and bipolar (HR = 1.92, 95% CI = 1.31 to 2.80; p < 0.001) hemiarthroplasty had higher revision risks than THA. In the age-stratified multivariable analysis of patients aged 60 to 79 years, both unipolar (HR = 2.17, 95% CI = 1.42 to 3.34; p = 0.004) and bipolar (HR = 1.69, 95% CI = 1.08 to 2.65; p = 0.022) hemiarthroplasty also had higher revision risks than THA. In the ASA-stratified multivariable analysis, patients with an ASA classification of I or II had a higher revision risk after either unipolar (HR = 3.52, 95% CI = 1.87 to 6.64; p < 0.001) or bipolar (HR = 2.31, 95% CI = 1.19 to 4.49; p = 0.013) hemiarthroplasty than after THA. No difference in revision risk between either of the hemiarthroplasties and THA was observed among patients with an age of ≥80 years or those with an ASA classification of III. Conclusions: In this study of hip fractures in older patients, THA was associated with a lower risk of all-cause revision compared with unipolar and bipolar hemiarthroplasty among patients who were 60 to 79 years old and those who had an ASA classification of I or II. Level of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.