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Trial registered on ANZCTR


Registration number
ACTRN12615000263594
Ethics application status
Approved
Date submitted
13/01/2015
Date registered
20/03/2015
Date last updated
27/05/2019
Date data sharing statement initially provided
27/05/2019
Type of registration
Prospectively registered

Titles & IDs
Public title
Bone Density Analysis of Rigid vs Elastic Uncemented Acetabular Cups in Patients with Symptomatic Arthritis of the Hip.
Scientific title
DEXA Analysis of Conventional Rigid vs. Elastic Uncemented Acetabular Cups in Patients with Symptomatic Arthritis of the Hip.
Secondary ID [1] 285801 0
Nil known
Universal Trial Number (UTN)
U1111-1164-9901
Trial acronym
DEXA Rigid vs. Elastic Study
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Symptomatic arthritis of hip 293694 0
Condition category
Condition code
Musculoskeletal 293995 293995 0 0
Osteoarthritis
Surgery 294635 294635 0 0
Other surgery

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
RM Pressfit Acetabular Cup. The cup is a cementless monoblock press-fit acetabular cup and it is manufactured from UHMWPE, which is stabilised with Vitamin E. The outer surface of the polyethylene is coated with titanium particles for bony in-growth.
This device has no metal shell, and is designed to be flexible in the acetabular bone, unlike a conventional uncemented acetabular cup.
A standard total hip replacement will be performed to implant the device, according to the individual surgeons normal practice.
Intervention code [1] 290775 0
Treatment: Devices
Intervention code [2] 291274 0
Treatment: Surgery
Comparator / control treatment
Rigid Uncemented Acetabular Cup. The cup is a conventional uncemented acetabular cup with a metal shell and polyethylene liner.
A standard total hip replacement will be performed to implant the device, according to the individual surgeons normal practice.
Control group
Active

Outcomes
Primary outcome [1] 293783 0
To investigate the acetabular bone stock when using a RM Pressfit Cup compared with a conventional rigid uncemented acetabular cup as assessed by DEXA analysis.

Timepoint [1] 293783 0
2 years
Secondary outcome [1] 311821 0
To investigate the acetabular bone stock when using a RM Pressfit Cup compared with a conventional rigid uncemented acetabular cup as assessed by DEXA analysis.
Timepoint [1] 311821 0
5 years
Secondary outcome [2] 311822 0
To examine whether the RM Pressfit Vitamys Cup performs as well as conventional acetabular cups with regards to function using the Oxford Hip Score. Average scores will be compared between the RM Pressfit Cup group and the comparison group.
Timepoint [2] 311822 0
5 years
Secondary outcome [3] 313502 0
To examine whether the RM Pressfit Vitamys Cup performs as well as conventional acetabular cups with regards to quality-of-life using the Short Form 36 (SF-36) and the Assessment of Quality of Life (AQoL-6D). Average scores for each assessment will be compared between the RM Pressfit Cup group and the comparison group.
Timepoint [3] 313502 0
5 years

Eligibility
Key inclusion criteria
1. Patients with symptomatic arthritis who are candidates for a primary total hip replacement with an uncemented or cemented femoral stem as determined jointly by the surgeon and the patient.
2. Patients suitable for an uncemented acetabular component
3. Patients who understand the conditions of the study and are willing to participate for the length of the prescribed follow-up
Minimum age
18 Years
Maximum age
70 Years
Gender
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
1. Patients who have had previous contralateral hip replacement surgery
2. Pregnant women or those seeking to become pregnant
3. Patients with a history of active infection
4. Patients with conditions or medications associated with osteoporosis or osteopenia ie: bisphosphonates, Protos, steroids and previous acetabular surgery on the affected side.
5. Patients who have severe arthritis of contralateral hip

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)
Patients who conform to the inclusion/exclusion criteria will be invited to join the study. If they agree, then a consent form will be signed and the treatment group will be randomised via central randomisation software. The patient will not be informed of which study group they have been assigned to prior to surgery.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Permuted block randomisation of equal allocations to each group.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s


Intervention assignment
Parallel
Other design features
Participants are randomised between the two study groups to receive either the test or control devices. Recruitment and randomisation continue until the sample size is complete.
Phase
Not Applicable
Type of endpoint(s)
Safety/efficacy
Statistical methods / analysis
The study has adequate power to determine if the bone density behind the Elastic Cup is maintained compared with the control group.
To estimate the sample group size the following parameters
were set:
1. Level of significance: a or p=0.05, 2 sided
2. Power level: 95%

Using a sample size formula to calculate the average for two groups; the sample size was calculated at 58 patients. This means that 58 patients per group are required to detect a 20% difference with a 95% confidence.

Allowing for a 25% withdrawal or loss to follow-up this will give 72 patients per group.

Recruitment
Recruitment status
Withdrawn
Reason for early stopping/withdrawal
Other reasons/comments
Other reasons
Surgeons decided not to proceed
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
VIC
Recruitment hospital [1] 3242 0
Epworth Richmond - Richmond
Recruitment postcode(s) [1] 9024 0
3121 - Richmond

Funding & Sponsors
Funding source category [1] 290376 0
Commercial sector/Industry
Name [1] 290376 0
Mathys Orthopaedics Pty Ltd
Address [1] 290376 0
Unit 6
15–17 Chaplin Drive
Lane Cove West
NSW 2066
Country [1] 290376 0
Australia
Primary sponsor type
Commercial sector/Industry
Name
Mathys Orthopaedics Pty Ltd
Address
Unit 6
15–17 Chaplin Drive
Lane Cove West
NSW 2066
Country
Australia
Secondary sponsor category [1] 289102 0
None
Name [1] 289102 0
Address [1] 289102 0
Country [1] 289102 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 292080 0
Epworth HealthCare Human Research Ethics Committee
Ethics committee address [1] 292080 0
89 Bridge Road
Richmond
VIC 3121
Ethics committee country [1] 292080 0
Australia
Date submitted for ethics approval [1] 292080 0
10/10/2012
Approval date [1] 292080 0
28/11/2012
Ethics approval number [1] 292080 0
56512
Ethics committee name [2] 292081 0
St John of God Health Care Ethics Commitee
Ethics committee address [2] 292081 0
12 Salvado Road
Subiaco
WA 6008
Ethics committee country [2] 292081 0
Australia
Date submitted for ethics approval [2] 292081 0
Approval date [2] 292081 0
10/10/2012
Ethics approval number [2] 292081 0
571

Summary
Brief summary
This clinical study is a prospective, randomised, multi-centre study that will enrol 144 patients over a 12-month recruitment period between three surgeons and three centres.
The objective of the study is to investigate if the Mathys RM Pressfit Cementless Cup maintains acetabular bone stock by reducing the effects of stress shielding when compared with a conventional rigid cementless acetabular cup. This study also aims to demonstrate safety, and equivalent clinical outcomes to standard care.
The RM Pressfit Cementless cup is designed to have a modulus of elasticity that is similar to bone, and therefore it may be possible to transfer physiological loads through the cup and prevent the bone behind the cup from resorbing due to stress shielding.
The control group for this study will be a standard hip replacement with a conventional rigid cementless acetabular cup.
Standard, functional parameters will be assessed pre-operatively, and post-operatively at 6 weeks, 6 months, 12 months, 2 years and 5 years.
Antero-posterior and lateral radiographs will be analysed at 6 weeks, 1 year and 5 years to assess femoral stem and acetabular cup orientation. DEXA (measures bone density) scans will be assessed pre-operatively at 6 weeks, 6 months, 12 months, 2 years and 5 years to measure acetabular bone density, with the aim of showing preservation of bone behind the RM Pressfit Cup when compared to a conventional rigid cup.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 53330 0
Prof Richard de Steiger
Address 53330 0
Orthopaedic Surgeon
26 Erin Street
Richmond
VIC 3121
Country 53330 0
Australia
Phone 53330 0
+61 3 9429 5580
Fax 53330 0
Email 53330 0
richard.desteiger@epworth.org.au
Contact person for public queries
Name 53331 0
Dr Jenny Burke
Address 53331 0
NeoSurgical Pty Ltd
17 Macarthur Avenue
Pagewood
NSW 2035
Country 53331 0
Australia
Phone 53331 0
+61 0488 240471
Fax 53331 0
Email 53331 0
jennyburke@neosurgical.com.au
Contact person for scientific queries
Name 53332 0
Dr Jenny Burke
Address 53332 0
NeoSurgical Pty Ltd
17 Macarthur Avenue
Pagewood
NSW 2035
Country 53332 0
Australia
Phone 53332 0
+61 0488 240471
Fax 53332 0
Email 53332 0
jennyburke@neosurgical.com.au

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
Study is not proceeding, therefore no data.
What supporting documents are/will be available?
No other documents available
Summary results
No Results