Title: DUALITY: Dual mobility (DM) versus standard articulation total hip replacement (THR) in the treatment of older adults with a hip fracture
Funder: Department of Health and Social Care

Abstract: BACKGROUND Worldwide there are 1.3 million hip fractures with more than 70,000 hip fractures in the UK every year; projected to rise to more than 100,000 by 2020 in the UK. The global cost of this clinical problem is estimated at 1.75 million disability adjusted life years lost and represents 1.4% of the total healthcare burden in established market economies. Some hip fractures are treated with a total hip replacement. The standard type of THR involves a single joint between a relatively small ball and the socket; with an associated risk of dislocation, where the ball disengages from the socket. Most patients who experience a dislocation go on to have recurrent dislocations and many undergo revision surgery. The mortality following second surgery for hip fractures approaches 50% in this frail group of patients; the functional outcome of revision hip replacement is less successful when compared with an index procedure. An alternative design, the dual mobility (DM) THR may be less likely to dislocate. Here, the ball and socket are still replaced but the small ball is encased in a much larger plastic ball; improving the stability of the hip replacement by increasing the range of movement of the joint prior to dislocation. RESEARCH QUESTION What is the clinical and cost effectiveness of dual mobility versus standard articulation total hip replacement in the treatment of adults aged 65 years and over with an acute, displaced intracapsular hip fracture? DESIGN International, pragmatic, multicentre, two-arm randomised controlled superiority trial with parallel economic analyses from a UK NHS perspective and direct patient follow-up to one year. Currently, the DUALITY study based in Sweden is open to recruitment; this UK component will recruit approximately one third of the overall sample. The UK component will be nested within the existing WHiTE PLATFORM and enabled by the National Joint Registry maximising value for money in setup and followup trial costs. METHODS All patients aged 65 and over with a displaced intracapsular fracture are potentially eligible to take part in this study. Eligible patients will be identified in daily trauma meetings and approached for recruitment prior to their treatment. Treatments will be performed in hospitals across the UK by a wide range of surgeons to ensure generalisability. 1600 participants will be randomly allocated to standard bearing or dual mobility total hip replacement. Other components of both interventions including patient position, implant choice and type of anaesthesia will be at the discretion of the clinical team. The trial will employ 1:1 random allocation by a remote computer system, stratified by centre. Data regarding quality of life, complications and costs will be collected at four and twelve months. The primary outcome measure is dislocation risk at 12 months from randomisation. TIMELINES FOR DELIVERY UK recruitment will commence in March 2022 and report in August 2024. IMPACT The 12-month results will be presented and published internationally. We expect the trial to be included in NICE hip fracture guideline (CG124) at their scheduled update in 2025.

Lay abstract: Every year around 70,000 people in the UK break their hip. Hip fractures are a common and very serious injury in older people, similar in impact to a major stroke. We will investigate two treatments for one specific type of hip fracture. Currently, surgeons use one of two types of total hip replacement, which is an operation to replace both the ball and socket of the hip joint. One type uses a small ball within the socket, in the other the ball is enclosed within a larger plastic ball; we do not know which is the better treatment. We will investigate which of these treatments gives a better result for people 65 years and over with hip fracture from 30 hospitals across the UK. We want to look at whether people have had any complications after their surgery, particularly dislocation, where the ball comes out of the socket. We will ask people how they feel and how active they are a year after their fracture. We will also work out the cost of the two treatments &ndash; for the individual, for the health service and in terms of social support in the following year. We have previously tried to answer this important question in a pilot study. We concluded that it wasn t possible to carry out the necessary study since it would need to be very large and expensive. Since then there has been greatly increased use of the alternative type of hip replacement without any evidence. We propose in this study to work with other European countries so that taken together we will be able to answer the question more quickly and at a cost that is reasonable. To compare the two treatments properly we think we will need 1600 people to take part overall, we anticipate that 450 will come from the UK part of the study. If people agree to take part, they will be put into one of two groups through a process called randomisation which makes sure that the groups are similar and the comparison is fair. After their operation everyone will have the usual ward care, rehabilitation and follow up that is standard practice at their hospital. The researchers will ask people about any complications from the surgery, their health, walking ability and other daily activities, as well as any additional costs. Answers will be collected at the time of the surgery, at 4 months and 1 year after the injury; the results from the two groups will then be compared. People will be asked for their permission for the research team to use personal information about them collected routinely by hospitals and the NHS so that longer term effects can also be investigated.

Research activity codes: 6.4 SURGERY
Health categories: INJURIES AND ACCIDENTS