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Trial registered on ANZCTR


Registration number
ACTRN12621000069853
Ethics application status
Approved
Date submitted
14/12/2020
Date registered
28/01/2021
Date last updated
14/07/2022
Date data sharing statement initially provided
28/01/2021
Type of registration
Prospectively registered

Titles & IDs
Public title
DISTINCT: Dual Mobility Versus Standard Total Hip Arthroplasty In Femoral Neck Fractures, A Registry-Nested, Cluster-Randomised Trial
Scientific title
DISTINCT: Hip Dislocation Occurrence in Dual Mobility Versus Standard Total Hip Arthroplasty In Femoral Neck Fractures, A Registry-Nested, Cluster-Randomised Trial
Secondary ID [1] 302924 0
None
Universal Trial Number (UTN)
U1111-1262-1221
Trial acronym
DISTINCT
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Hip fracture 319941 0
Dislocation 319942 0
Total Hip Replacement 319943 0
Condition category
Condition code
Surgery 317880 317880 0 0
Other surgery
Injuries and Accidents 318236 318236 0 0
Fractures

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Dual mobility cup (DMC) has been proposed as an alternative, novel design for Total Hip Arthoplasty (THA) that is purported to reduce the risk of dislocation in high-risk populations such as femoral neck fractures. This is achieved by use of a larger head-to-neck ratio and jump distance (i.e. vertical or inferior head displacement required for dislocation) that approximates the size of the natural femoral head allowing an increased range of motion in all directions before dislocation occurs.
The surgery to implant the DMC is the same procedure as implanting a conventional THA, and takes approximately 90 minutes. The only aspect of the procedure that changes is the type of acetabular ('hip socket') liner inserted. The procedure is performed by an Orthopaedic surgeon.
Adherence to the study protocol will be determined using standard Australian Orthopaedic Association National Joint Replacement Registry data (prosthesis details). Both primary and revision surgeries recorded by the AOANJRR are validated by cross-referencing with hospital-level data and unmatched revisions are verified by contacting individual sites.
The study will use a cluster-randomised crossover design. Clusters will consist of individual hospitals. Clusters will be randomised to either the intervention or the comparator. Sites will crossover to the alternate procedure once 16 patients have been recruited to their originally allocated study arm. The number of patients per cluster may vary according to recruitment speeds. For example, a low volume recruitment site may crossover after 8 patients have been recruited, and a high volume recruiment site may crossover after 24 patients have been recruited. This will be accounted for in statistical analyses for an average cluster size of 16 patients per study arm, with 32 patients total anticipated on average per site.
Intervention code [1] 319209 0
Treatment: Surgery
Comparator / control treatment
Conventional Total Hip Arthroplasty (CTHA) involves replacing the femoral head (ball) and acetabulum (socket) of the hip joint. However, compared to the DMC, there is only one bearing surface between the prosthetic femoral head and acetabulum. The surgical procedure is identical, and takes approximately 90 minutes. CTHA is routinely performed by Orthopaedic surgeons for the treatment of femoral neck fractures. Adherence to the study protocol will be determined using standard Australian Orthopaedic Association National Joint Replacement Registry data (prosthesis details). Both primary and revision surgeries recorded by the AOANJRR are validated by cross-referencing with hospital-level data and unmatched revisions are verified by contacting individual sites.
Control group
Active

Outcomes
Primary outcome [1] 325896 0
Hip dislocation: identified information collected at the time of primary hip replacement will be used to link Registry (and therefore DISTINCT study) data with hospital level data acquired through state governments or the Australian Institute for Health and Welfare (AIHW) to determine dislocation using patient identifiers.
Timepoint [1] 325896 0
Within 1 year post-operatively
Secondary outcome [1] 389458 0
Revision surgery for dislocation: AOANJRR already collects data on almost all joint replacement procedures performed in Australia. The operative data are completed at the time of surgery on a Registry form. The forms include a section where the operating surgeon reports the indication for revision surgery. These forms are collated each month by the hospital and sent to the Registry for data entry into the secure Registry database. Revision surgical procedures are thereafter linked to the primary surgical procedure by Registry staff using patient identifiers. This process will remain unchanged.
Timepoint [1] 389458 0
Assessed at 1, 2 and 5 years post-operatively
Secondary outcome [2] 389459 0
Revision surgery for any reason: AOANJRR already collects data on almost all joint replacement procedures performed in Australia. The operative data are completed at the time of surgery on a Registry form. The forms include a section where the operating surgeon reports the indication for revision surgery. These forms are collated each month by the hospital and sent to the Registry for data entry into the secure Registry database. Revision surgical procedures are thereafter linked to the primary surgical procedure. This process will remain unchanged.
Timepoint [2] 389459 0
Assessed at 1, 2 and 5 years post-operatively
Secondary outcome [3] 389460 0
Death: the AOANJRR links to the National Death Index (Australian Institute for Health and Welfare) twice a year in order to flag if a patient is deceased. The process is unchanged.
Timepoint [3] 389460 0
Assessed at 1, 2 and 5 years post-operatively
Secondary outcome [4] 389461 0
Complications: any unplanned reoperation or readmission related to the surgery. Identified information collected at the time of primary hip replacement will be used to link Registry (and therefore DISTINCT study) data with hospital level data acquired through state governments or the Australian Institute for Health and Welfare (AIHW) to determine dislocation using patient identifiers.
Timepoint [4] 389461 0
Within 1 year post-operatively
Secondary outcome [5] 389462 0
Costs: if DMC is found to be superior to conventional THA, the cost-effectiveness will be analysed. The cost-effectiveness of DMC versus CTHA will be analysed using trial data in a separate manuscript to the DISTINCT trial. Direct costs to the hospital for each procedure will be determined from hospital financial records.
Timepoint [5] 389462 0
Assessed at 1, 2 and 5 years post-operatively.

Eligibility
Key inclusion criteria
1. Displaced femoral neck fracture suitable for conventional THA (e.g. no pre-existing deformity requiring custom or non-standard protheses)
2. Aged 50 years or older
3. Patient meets Australia New Zealand Hip Fracture Guidelines for management of a
displaced intracapsular hip fracture with a total hip replacement:
4. Able to walk independently out of doors with no more than use of a stick prior to the
fracture
5. Not cognitively impaired
6. Medically fit for anaesthesia and the procedure
Minimum age
50 Years
Maximum age
No limit
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
1. Dementia or other significant cognitive impairment
2. Resident of a permanent residential aged care facility
3. Pathological fracture due to tumour

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation is not concealed.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Each site will be randomised with a 1:1 allocation with a computer-generated random sequence. Simple randomisation will be used (no use of blocks, no stratification). The allocation will refer to the first intervention.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?



The people analysing the results/data
Intervention assignment
Other
Other design features
Cluster-randomised crossover trial
Sites will not be blinded to group allocation. Patients will be informed of a study comparing two different but common types of THA used for fractured neck of femur.
The statistical analysis will be blinded. The Writing Committee will be blinded and will prepare two separate manuscripts based on the possible group allocations.
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
The analysis for the primary aim will test between-group difference in the proportion of cases sustaining a dislocation of the affected hip within one year post-operatively.
The primary analysis will use cluster summary methods. These methods estimate the treatment effect using cluster level differences and have been shown to be appropriate for cluster randomised crossover trials with rare outcomes and the intracluster and interperiod correlation coefficients expected in this trial. Multiple imputation will be used to account for missing outcome data, using auxiliary variables gathered from routine Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) data (including age, sex, baseline health, pain and function, diagnosis and surgical factors).
Secondary analyses will be performed for the primary outcome, to test for differences in treatment effect between subgroups of patients: surgical approach, ASA grade, BMI grade and gender.
The analysis method will be the same as the primary outcome and will include an interaction term between subgroup and treatment group.
Secondary analyses will include an analysis of all-cause revision, revision for dislocation, and other complications (death, re-operation and readmission rates). Cluster summary methods will be used for all secondary analyses.
If DMC are found to be superior to conventional THA, a cost effectiveness analysis of DMC compared to conventional THA will be performed from a health system perspective, calculating the cost per dislocation saved. The only difference in input costs will be the difference in implant costs, as all other care costs will be equal.

Recruitment
Recruitment status
Recruiting
Date of first participant enrolment
Anticipated
1/02/2021
Actual
1/02/2021
Date of last participant enrolment
Anticipated
1/02/2023
Actual
Date of last data collection
Anticipated
1/02/2028
Actual
Sample size
Target
1536
Accrual to date
1145
Final
Recruitment in Australia
Recruitment state(s)
ACT,NSW,QLD,SA,TAS,WA,VIC

Funding & Sponsors
Funding source category [1] 307347 0
Charities/Societies/Foundations
Name [1] 307347 0
Australian Orthopaedic Association National Joint Replacement Registry
Country [1] 307347 0
Australia
Primary sponsor type
Charities/Societies/Foundations
Name
Australian Orthopaedic Association
Address
Level 26, 201 Kent St, Sydney NSW 2000
Country
Australia
Secondary sponsor category [1] 307986 0
None
Name [1] 307986 0
Address [1] 307986 0
Country [1] 307986 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 307434 0
Sydney Local Health District Ethics Review Committee (RPAH Zone)
Ethics committee address [1] 307434 0
Research Ethics and Governance Office
55 Missenden Rd
Royal Prince Alfred Hospital
CAMPERDOWN NSW 2050
Ethics committee country [1] 307434 0
Australia
Date submitted for ethics approval [1] 307434 0
29/02/2020
Approval date [1] 307434 0
28/05/2020
Ethics approval number [1] 307434 0
X20-0162 & 2020/ETH00680

Summary
Brief summary
Fractured neck of femur (FNF) is a common condition, affecting 25,000 Australians per annum. Total hip arthroplasty (THA), which involves replacing the ball and socket of the hip joint, is the current standard of care for fractured neck of femur in community-dwelling patients with minimal co-morbidities. However, despite superior pain and functional scores compared to the alternative treatment, partial hip replacement (hemiarthroplasty), THA exposes patients to an increased risk of prosthesis dislocation. Prosthesis dislocation involves separation of the prosthetic head and acetabular cup, and may require a patient to undergo revision THA, a procedure associated with increased costs and morbidity. Dual mobility cups (DMC) are an alternative THA design in common use in Australia, and are hypothesised to reduce the risk of dislocation. This trial will compare the outcomes of conventional THA versus DMCs in the FNF population.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 107222 0
Prof Ian A. Harris
Address 107222 0
Whitlam Orthopaedic Research Centre
Level 2, Ingham Institute, 1 Campbell St, Liverpool NSW, 2170
Country 107222 0
Australia
Phone 107222 0
+61 410698284
Fax 107222 0
Email 107222 0
[email protected]
Contact person for public queries
Name 107223 0
Tamara Hooper
Address 107223 0
SAHMRI
North Terrace
ADELAIDE SA 5000
Country 107223 0
Australia
Phone 107223 0
+61 8 8128 4598
Fax 107223 0
Email 107223 0
[email protected]
Contact person for scientific queries
Name 107224 0
Ian A. Harris
Address 107224 0
Whitlam Orthopaedic Research Centre
Level 2, Ingham Institute, 1 Campbell St, Liverpool NSW, 2170
Country 107224 0
Australia
Phone 107224 0
+61 410698284
Fax 107224 0
Email 107224 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
Yes
What data in particular will be shared?
Primary and secondary outcomes
When will data be available (start and end dates)?
Following dissemination of the results in a peer-reviewed journal (expected publication 2025).
There is no end date planned for availability of data.
Available to whom?
Researchers who make a written request to the Chief Investigator (IAH) for the purposes of collaborative analysis of trial data.
Available for what types of analyses?
Individual patient data meta-analyses
How or where can data be obtained?
Access subject to approval by Chief Investigator (IAH). Ian A. Harris can be contacted at [email protected].


What supporting documents are/will be available?

Doc. No.TypeCitationLinkEmailOther DetailsAttachment
9922Study protocol    381041-(Uploaded-03-12-2020-08-16-47)-Study-related document.pdf



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
SourceTitleYear of PublicationDOI
EmbaseDual mobility versus conventional total hip arthroplasty in femoral neck fractures (DISTINCT): protocol for a registry-nested, open-label, cluster-randomised crossover trial.2022https://dx.doi.org/10.1136/bmjopen-2022-064478
N.B. These documents automatically identified may not have been verified by the study sponsor.