Dual-Mobility Hip Implant Cuts Postoperative Dislocations

Femoral neck fractures, a common type of hip fracture in older adults, often require total hip replacement. Postoperative dislocation of the artificial hip remains a persistent problem that can cause severe pain and unplanned procedures. This complication burdens patients and hospitals through sedation, repeat surgery, and prolonged care. A new international study shows that a dual-mobility total hip replacement can markedly reduce the risk of dislocation after surgery.

Researchers at Uppsala University and Queen Mary University of London evaluated a dual-mobility total hip replacement (DM THR). The implant encloses a small femoral head within a larger plastic ball to increase stability and resist dislocation. The approach targets instability without changing standard operative workflows or surgical exposure.

The study enrolled 1,600 patients aged 65 years or older with femoral neck fractures at 44 hospitals in Sweden and the United Kingdom. Participants suitable for total hip replacement were randomly assigned to receive a dual-mobility cup or a standard cup. The trial, named Duality, is described as an international, multicenter, randomized, controlled, superiority trial and was published online in The Lancet on July 2, 2026.

At one year, the risk of hip dislocation was 70% lower with the dual-mobility cup. Dislocation occurred in 1.3% of patients in the dual-mobility group compared with 4.2% with a traditional cup. The overall risk of surgical complications was also lower with the dual-mobility design. There were no between-group differences in implant infection, mortality, or quality of life during the first postoperative year.

Although dual-mobility implants are currently more expensive than standard implants, the investigators report that a full health economic analysis is underway to assess whether the reduction in complications offsets higher upfront costs. The study team also notes that the implant change does not require new technology or additional training.

“No one has previously conducted such a large study in which patients were randomly assigned to either a dual-mobility cup or the standard type of cup. It is very significant that we did not limit participation to university hospitals, but instead included smaller hospitals from a variety of locations in both countries, even from places without extensive research experience,” said Nils Hailer of Uppsala University. 

“Together, surgeons in Sweden and the UK succeeded in delivering a large, pragmatic orthopaedic randomised trial involving both smaller hospitals and major referral centres across two countries. Beyond the findings themselves, we believe this collaboration sets a new benchmark for future randomized trials in European orthopaedic research,” added Hailer.

Related Links
Uppsala University
Queen Mary University of London