Lancet - 2026-07-02 - Journal Article
Dual mobility versus standard cups in total hip replacement for displaced femoral neck fractures (Duality): an international, multicentre, randomised, controlled, superiority trial.
Hailer NP, Griffin XL, Mukka S, Lakic TG, Appelbe D, Sköldenberg O, Lamb SE, Östlund O, Wolf O, DUALITY Investigators
Topics
Key Takeaway
Dual mobility THA reduced dislocation risk by 73% versus standard THA in displaced femoral neck fractures (1.3% vs 4.2%; aHR 0.27, 95% CI 0.13–0.56) at one year.
Summary Depth
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Summary
The Duality trial asked whether dual mobility THA reduces dislocation versus standard THA in patients ≥65 years with displaced femoral neck fractures across 44 Swedish and UK centers. Patients were randomized 1:1 to DM-THR or standard THR using registry-based remote allocation; neither patients nor treating surgeons were blinded. Dislocation occurred in 1.3% of DM-THR versus 4.2% of standard THR patients (aHR 0.27, 95% CI 0.13–0.56; p<0.0001), with DM-THR also reducing overall surgical complications.
Key Limitation
One-year follow-up captures early dislocation but does not address long-term dual mobility–specific failure modes including intraprosthetic dislocation, liner wear, and aseptic loosening that emerge beyond 5–10 years.
Original Abstract
BACKGROUND
Dislocation is the most common early surgical complication in patients with hip fractures treated with total hip replacement (THR). Dual mobility total hip replacement (THR) was developed to increase joint stability, but no randomised trial has investigated its efficacy and safety. We aimed to compare the risk of dislocation in patients receiving DM-THR versus conventional THR.
METHODS
We included people aged 65 years or older with a displaced femoral neck fracture attending 20 Swedish and 24 UK hospitals in this pragmatic, registry-based, randomised superiority trial. Participants eligible for THR were randomly allocated in a 1:1 ratio to either DM-THR or standard THR with the use of remote, web-based, country-specific sequences. Neither participants nor members of the direct clinical care teams were masked, but research investigators and statisticians were masked until the trial analysis was completed. The primary outcome was dislocation of the index joint, treated with closed reduction or open surgery within 1 year, analysed in the modified intention-to-treat population including all consenting participants receiving any type of hip replacement and excluding those with major protocol deviations. This trial is registered with ClinicalTrials.gov (NCT03909815) and ISRCTN11895196.
FINDINGS
Between Jan 9, 2020, and April 2, 2024, 2934 eligible patients were screened, of whom 1334 were not enrolled, mainly due to surgeon's preference (n=560), because they had already been treated at the time of screening (n=257), or because informed consent was not obtained (n=213). 1600 participants (64% female, 36% male) were thus randomly assigned to either DM-THR (n=798) or THR (n=802). After exclusion of 34 participants due to prespecified protocol deviations, 1566 participants (97·9%) contributed to the modified intention-to-treat analysis. A dislocation, the primary outcome, occurred in ten (1·3%) of 779 participants in the DM-THR group and in 33 (4·2%) of 787 in the THR group (adjusted hazard ratio 0·27, 95% CI 0·13-0·56; p<0·0001).
INTERPRETATION
The use of DM-THR substantially reduced the risk of dislocation and of any surgical complication among people treated with THR after a displaced femoral neck fracture. DM-THR can thus be recommended for this group of patients.
FUNDING
The Swedish Research Council and the National Institute for Health and Care Research.