Dual mobility vs standard hip replacement (DUALITY)

Overview

This study asked whether a newer type of hip replacement implant, called a dual mobility implant, reduced complications compared with standard implants in people with a broken hip. 

It focused on older adults with certain types of hip fracture who required a total hip replacement. These injuries are common worldwide and can have serious impacts on recovery, mobility and independence. 

The international DUALITY trial involved around 1,600 patients treated across 44 hospitals in the UK and Sweden. It was the largest study of its kind and aimed to provide clear evidence about whether dual mobility implants improved patient outcomes after surgery.

What we found

The study found clear benefits of dual mobility implants compared with standard hip replacements.

• Patients receiving dual mobility implants were more than 70% less likely to experience hip dislocation 
• Dislocation rates within one year: 
  • 1.3% with dual mobility implants 
  • 4.2% with standard implants 
• Dislocation, a common complication, often led to emergency care, additional procedures or repeat surgery 
• Patients with dual mobility implants were around three times less likely to need further surgery (inferred from headline; no detailed figure provided) 
• There was no increase in risk of infection or death 
• Overall complication rates were lower in the dual mobility group 
• Dual mobility implants improved stability by using a design with two moving parts, making the joint less likely to slip out of place.

Why it matters

The findings suggested that dual mobility implants could improve outcomes for older patients with hip fractures by reducing complications that delay recovery and increase distress. 

In practice, fewer dislocations would likely mean: 

Shorter hospital stays 

Fewer emergency admissions 

Less need for additional operations 

Although dual mobility implants were more expensive upfront, the study suggested these costs could be offset by savings from avoiding complications. A full economic analysis was still underway, so the exact cost impact was not yet known. 

Importantly, no new training or technology was required, meaning surgeons could adopt this approach immediately within existing practice. 

The researchers concluded that dual mobility implants should be considered the preferred option for suitable patients. The study also demonstrated the value of large international trials, helping to answer long-standing clinical questions and informing future orthopaedic research. 

Outputs and reach

The main findings were published in The Lancet. 

The international collaboration between UK and Swedish researchers helped deliver one of the largest trials in this area and set a benchmark for future research. 

A full economic analysis was ongoing at the time of reporting. 

You can find out more here

Who was involved

The study was led by Professor Xavier Griffin at Queen Mary University of London and Professor Nils Hailer at Uppsala University. 

It brought together researchers and clinicians across 44 hospitals in the UK and Sweden, supported by the National Institute for Health and Care Research (NIHR) and the Swedish Research Council. 

The collaboration built on strong existing partnerships in bone and joint health research, including work across NIHR Biomedical Research Centres with colleagues in Oxford and Exeter.