Dual Mobility versus Conventional Total Hip Arthroplasty for Femoral Neck Fractures: A Multicenter Propensity-Matched Study on Dislocation Risk.

Abstract

Total hip arthroplasty (THA) is a common treatment for displaced femoral neck fractures (FNF). Dual mobility (DM) THA has been advocated to reduce dislocation risk in high-risk patients, such as those who have FNF. However, comparative studies remain limited. The purpose of our study was to answer the following questions: (1) What is the dislocation incidence between DM-THA and conventional THA (c-THA) in patients who have FNF? (2) What is the revision incidence between DM-THA and c-THA in patients who have FNF? and (3) What are the risk factors for dislocation in patients who have THA for FNF? A multicenter retrospective cohort study involving 822 patients who underwent THA for displaced FNF at four public hospitals between 2012 and 2020 was conducted. Propensity matching (2:1) balanced age, sex, American Society of Anesthesiologists (ASA) score, surgical approach, and surgeon experience to analyze dislocation and revision incidence between DM-THA and c-THA. Kaplan-Meier survival analysis and multivariable logistic regressions were performed. Following propensity matching (209 DM-THA versus 418 c-THA), DM-THA demonstrated lower dislocation incidence up to five years (0.5% [95% confidence interval (CI) 0 to 2.5%] versus 4.8% [95% CI 3.0 to 7.2%], P = 0.005). However, there was no difference in revision for instability (DM THA: 0.5% versus c-THA: 2.0%; P = 0.2) or revision for all causes (DM THA: 3.1% versus c-THA: 3.9%; P = 0.3). Use of DM-THA reduces dislocation risk in FNF without increasing overall revision incidence, supporting its use in high-risk patients.