Condition category
Musculoskeletal Diseases
Date applied
06/03/2012
Date assigned
21/03/2012
Last edited
16/08/2013
Prospective/Retrospective
Prospectively registered
Overall trial status
Completed
Recruitment status
No longer recruiting

Plain English Summary

Background and study aims
A total hip replacement (THR) is used in the treatment of severe and debilitating arthritis of the hip; the natural, arthritic ball and socket joint is removed and replaced with an artificial prosthesis, or implant.
A THR implant (also known as prosthesis) comes in four pieces; a stem, a head, a liner and a cup. These all fit together; the head and the liner form the ball and socket part of the joint. The head sits on the stem, and the liner fits in the cup. The stem sits inside the thigh-bone (femur) and the cup sits in the pelvic bone. It is important in THR that the stem and the cup are well fixed in place and do not move within the bone. This type of movement, referred to as migration, is linked with early to mid-term failure of the implant, and can require re-operation.
The orthopaedic manufacturer De Puy developed a stem called the 'Corail', which has been shown to have minimal migration, and is the most commonly used implant in THR. It has two versions, one with a collar and one without. It is not known whether the presence of the collar helps prevent excessive migration.
This has led to the development of the 'Polar' stem by the orthopaedic manufacturer Smith & Nephew, which is similar in design to the Corail, but has not been directly compared in performance to the Corail.
The first aim of this study is to assess the relative migration of the Polar and the Corail stems over a 2-year period in THR to see whether the Polar performs comparably or even better than the Corail. The second aim is the comparison of migration of the cementless R3 cup with a well-established cementless comparison by using radiostereometric analysis (RSA). This trial has been designed to document the migration of the implants over 2 years via x-ray analysis and clinical outcomes.

Who can participate?
Participants will be recruited from one NHS institution, and will be male or female adults, aged between 50-75 years, who have a diagnosis of debilitating hip arthritis and require THR.

What does the study involve?
The study will involve radiostereometric analysis (RSA) x-ray, which is a widely used method of measuring implant movements. It involves the insertion of 1-mm spherical tantalum markers around the prosthesis and x-rays being taken at intervals to show any change in relative position. These metallic markers are easy to identify on x-rays, do not cause a reaction in the body and have no known side-effects. Subjects will undergo THR with one of three possible hip arthroplasty stems: the Corail collared stem, the Corail collarless stem or the Polar stem, and the tantalum markers will be inserted at the time of surgery. RSA is then used as part of routine follow-up after the operation, to measure any migration of the stem.

What are the possible benefits and risks of participating?
The benefits may include identifying a superior prosthesis in terms of migration, resumption of high levels of function and overall patient satisfaction. There are risks associated with THR surgery. However, all implants used in the study have the CE mark, and are used routinely in many hospitals by many surgeons. There are no additional risks associated with participating in this study in comparison to an identical patient receiving an identical THR. The tantalum metallic markers do not cause a reaction in the body and have no known side-effects. There are no extra burdens associated with the study, as patients will return for clinical and RSA follow-up at 6 weeks, 6 months, 1 and 2 years after the operation, identical to those patients who are not in the study.

Where is the study run from?
University College Hospital NHS Foundation Trust (UK).

When is study starting and how long is it expected to run for?
It is anticipated to begin July 2012 and run until July 2015.

Who is funding the study?
The study is part funded by Smith and Nephew Orthopaedic, who developed the Polar THR.

Who is the main contact?
Professor Fares Haddad, c/o Fiona Felix, Trauma & Orthopaedics, G/F 250 Euston Road, London NW1 2PG

Trial website

Contact information

Type

Scientific

Primary contact

Prof Fares Haddad

ORCID ID

Contact details

Trauma & Orthopaedics
Ground Floor 250 Euston Road
London
NW1 2PG
United Kingdom

Additional identifiers

EudraCT number

ClinicalTrials.gov number

Protocol/serial number

N/A

Study information

Scientific title

A prospective, randomised, single centre clinical study comparing cementless Polar stem and the cementless Corail stem in total hip replacement

Acronym

Study hypothesis

The null hypothesis is that there is no difference in migration rates of the Corail or Polar stems at 2 years.

Ethics approval

Not provided at time of registration

Study design

Prospective randomised single centre clinical study

Primary study design

Interventional

Secondary study design

Randomised controlled trial

Trial setting

Hospitals

Trial type

Treatment

Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet

Condition

Hip osteoarthritis, total hip replacement

Intervention

The 75 patients recruited to the study will be randomly allocated to one of 3 groups:
1. Polar stem + R3 cup
2. Corail collarless + Pinnacle cup
3. Corail collared + Pinnacle cup

Each patient will have a 1:3 chance of receiving either the Polar stem and R3 cup, the Coral collarless stem and Pinnacle cup or the Corail collared stem and Pinnacle cup; they will not be aware of the prosthesis they have received until the end of the study. Although it is possible to randomise and blind the prosthesis to the patient and the Researcher gathering outcome data, it is not possible to blind the surgeon on the day of surgery.

Surgery will be performed and routine post-operative care provided, which includes rehabilitation and safe discharge from hospital. Each particicpant, regardless of each treatment arm, will receive identical care. A post-operative Radiostereometric Analysis (RSA) xray will be performed prior to discharge, and each participant will then be seen at 6 weeks, 6 months, 1 and 2 years post-op for RSA images and clinical follow-up.

Intervention type

Other

Phase

Not Applicable

Drug names

Primary outcome measures

Comparison of migration of the cementless Polar stem (Smith & Nephew Orthopaedics) with a well established cementless collarless and collared comparison stem (Corail, DePuy Orthopedics) in THR, by using RSA.

Secondary outcome measures

1. Comparison of migration of the cementless R3 cup (Smith & Nephew Orthopaedics) with a well established cementless comparison (Pinnacle, DePuy Orthopedics) by using RSA.
2. Documenting the performance of the Polar and Corail implants in the clinical setting over two years post-operatively, using information on infection and complication rates and specific Health Related Quality of Life (HRQoL) outcome / satisfaction scores to see whether there is any difference in performance.

Overall trial start date

01/07/2012

Overall trial end date

01/07/2015

Reason abandoned

Eligibility

Participant inclusion criteria

1. The surgeon and the patient must agree that total hip replacement (THR) is necessary
2. The patient must be fit for THR in the opinion of the surgeon and the interdisciplinary team
3. The indication for THR must be primary osteoarthritis, avascular necrosis, femoral neck fracture, or hip dysplasia
4. Patients requiring primary arthroplasty
5. Patients must be aged between 50 – 75 years at the time of surgery
6. Both male and female
7. The patient must be capable of giving informed consent and express a willingness to comply with the post-operative review program
8. The patient must be a permanent resident in an area accessible to the study site

Participant type

Patient

Age group

Adult

Gender

Both

Target number of participants

75

Participant exclusion criteria

1. Post-traumatic OA (proximal femur fracture)
2. Post-infection in respective joint
3. Prior osteotomy of the affected hip
4. Patients under treatment for osteoporosis (with bisphosphonate)
5. OA patients diagnosed Charnley Classification
6. Patients requiring cortisone medication
7. Patients whose body mass index is higher than 35
8. Patients already participating in the RSA hip study.
9. The individual is unable or unwilling to sign the patient informed consent specific to this study
10. Previous THR on contra-lateral side
11. Patients requiring revision arthroplasty

Recruitment start date

01/07/2012

Recruitment end date

01/07/2015

Locations

Countries of recruitment

United Kingdom

Trial participating centre

Trauma & Orthopaedics
London
NW1 2PG
United Kingdom

Sponsor information

Organisation

Joint UCL / UCLH / Royal Free Biomedical Research Unit (UK)

Sponsor details

Ground Floor
Rosenheim Wing
25 Grafton Way
London
WC1E 6DB
United Kingdom

Sponsor type

Research council

Website

Funders

Funder type

Industry

Funder name

Smith & Nephew Orthopaedics (UK)

Alternative name(s)

Funding Body Type

Funding Body Subtype

Location

Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Results - basic reporting

Publication summary

Publication citations

Additional files

Editorial Notes