Osteoarthritis, KneeNCT02482493
All Polyethylene Versus Metal Backed Tibial Components in Knee Replacement
A study testing Sigma PFC in people with Osteoarthritis, Knee, run by Maidstone & Tunbridge Wells NHS Trust at 1 site in United Kingdom.
Trial summary
Total knee arthroplasty (TKA) is one of the most commonly performed orthopaedic procedures. Approximately 84,000 knee replacement procedures were recorded in the UK in 2012. The main goal of TKA is to relieve the disabling pain of arthritic disease. Read more about this study
- Who is it for?
- Ages 75 years and olderHealthy volunteers can take part
- Conditions the study is for
- Osteoarthritis, Knee
- What is being tested?
- Sigma PFC
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 88 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- Jan 2017to Jul 2027
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 75 years and older
- All sexes
- Healthy volunteers accepted
- Older adult
Who may be able to join
- Patients suitable for simple cemented primary knee arthroplasty
- Patients presenting with osteoarthritis of the knee
- Patients with inflammatory arthropathy, requiring total knee arthroplasty
- Patients must be ambulatory at time of preoperative assessment clinic
- Patients must be able to understand instructions and be willing to return for follow up
- Patients aged 75 years or over at the time of surgery
Who cannot join
- Previous knee surgery (except arthroscopic / open meniscectomy)
- Patients with significant medical co-morbidity
- Disorders causing abnormal gait or significant pain
- Patients unable to consent
- Severe visual impairment
Trial locations and contacts
1 site in 1 country.
United Kingdom1 site
Trauma & Orthopaedic Dept, Tunbridge Wells Hospital
Pembury, Kent, TN2 4QJ
About this study
Official title: A Prospective Randomised Control Trial to Compare Clinical and Radiological Outcomes of the Press-Fit Condylar All-Polyethylene Tibial Component With Metal-Backed Tibial Component Implant, in Patients Aged 75 Years or Over
Total knee arthroplasty (TKA) is one of the most commonly performed orthopaedic procedures. Approximately 84,000 knee replacement procedures were recorded in the UK in 2012. The main goal of TKA is to relieve the disabling pain of arthritic disease.
Patient satisfaction following TKA is related to quick recovery and return to daily activities. This can be dependent on the design of the implant used in the knee. Improvements in implant design and surgical technique mean many modern designs offer implant survival rates beyond 10 - 15 years.
Read more
As cost pressure increases in the NHS the unit cost of implants is now being scrutinised, particularly with regard to cost effectiveness. The Press-Fit Condylar (PFC) Sigma implant can be used with either a conventional metal backed or alternatively an all polyethylene tibial component (part fitted to the shin bone), the latter considerably cheaper to manufacture. Four small prospective randomised trials and one large regional registry study with long follow up support the safe use of all polyethylene tibial components in TKA. The investigators will therefore undertake a prospective randomised controlled trial comparing the results of all polyethylene tibial components with those of conventional metal backed tibial components in patients aged 75 or over, comparing both clinical outcome and radiological survivorship.
The type of knee replacement used for each patient (metal-backed or polyethylene) will be chosen at random once a patient has agreed to take part in the study.
Data will be collected by means of follow-up appointments and questionnaires and clinical tests both before the operation 1 year, 2 years and 5 years postoperatively. This will allow us to see how both types of knee replacement perform over time and if one performs better than the other in terms of patients movement, pain and functional activities.
Read the detailed description
Summary of design and methodology.
When a patient who is appropriate for the study is added to the waiting list for a Total Knee replacement they will be given (or if missed, posted) an information sheet about the study. This will allow patients several weeks to read the information and telephone the Orthopaedic research department, if they wish, with any questions they may have.
The Patients will then come to preassessment clinic as usual. At this point the study will be explained again in person, the patient will be given time to ask questions and will be asked if they wish to consent to participating.
If the patient consents to taking part they will complete preoperative measures and questionnaires There are 3 questionnaires on how the patient is functioning. 2 are completed by the patient and 1 with the help of the Researcher
The questionnaires are:
Oxford Knee Score American Knee Society Score (AKSS) Medical Outcomes Study Short Form-36 Health Survey (MOS SF-36) All questionnaires will be performed preoperatively, 1 year, 2 years and 5 years postoperatively.
Six weeks postoperatively the patient will attend a follow-up clinic. This is standard for all patients undergoing knee replacement surgery at the Tunbridge Wells Hospital. Routine wound checks and postoperative care will take place and any patient's concerns dealt with. At this point the patient will be booked in for another routine follow up appointment 3 months postoperatively. No study data will be collected at these visits besides adverse events or lost to follow-up where appropriate.
At one year post-operatively the patient will be asked to attend for an appointment. The knee will be assessed clinical and same series of clinician and patient questionnaires completed. A series of x-rays will also be taken to allow the position of the implant to be recorded. Measurements will be taken to be taken from the x-rays Similarly the patient will be invited to attend a further 2 appointments at 2 year and 5 years post-operatively. At these appointments the questionnaires will be repeated along with the x-rays.
Should the patient wish to withdraw at any point they are free to do so and will not then be contacted for any subsequent appointments unless they are due routine clinical appointments .
Any patient undergoing total knee replacement and not in the study will attend routine 6 week and 3 month and one year follow-up appointments, as routine but will be discharged when appropriate and will not be subject to long term follow-up.
- Conditions
- Osteoarthritis, Knee
- Being tested
- Sigma PFC
- Medical subject headings
- Osteoarthritis, Knee
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Sigma PFCDevice
patients will receive either an all polyethylene tibial component or a metal- backed component
| Study group | Role | What they receive |
|---|---|---|
| All-polyethylene Tibial component | Active comparator | Sigma PFC All polyethylene Tibial component will be implanted Receives: Device: Sigma PFC |
| Metal Backed Tibial component | Active comparator | Sigma PFC metal-backed tibial component will be implanted Receives: Device: Sigma PFC |
What is being measured
The primary outcome is the main question the study is designed to answer.
American Knee Society Score
Measured: 5 year outcomes
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Jun 2015 (estimated)
- Study startJan 2017
- Primary completionJul 2027 (estimated)
- Study completionJul 2027 (estimated)
Why it stopped: initially stopped recruitment in COVID pandemic, now different prosthesis being use in the Sponsor NHS Trust, unlikely study will restart.
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Osteoarthritis, KneeStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 88 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Maidstone & Tunbridge Wells NHS Trust
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Helen Samuel, Maidstone & Tunbridge Wells NHS Trust
- Investigators
- Paul Gibb, Principal investigator, Maidstone and Tunbridge Wells NHS trust
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02482493
- Sponsor's protocol ID
- 14/01/282 version 1.3
- Status last verified
- Jul 2026
- First submitted
- 17 Jun 2015
- Last updated
- 29 Jul 2026
- Results posted
- No
- Data monitoring committee
- No
Study at a glance
From the registry record, last updated by the sponsor on 29 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Prospective Randomised Control Trial to Compare Clinical and Radiological Outcomes of the Press-Fit Condylar All-Polyethylene Tibial Component With Metal-Backed Tibial Component Implant, in Patients Aged 75 Years or Over
- ClinicalTrials.gov ID
- NCT02482493
- Acronym / sponsor ID
- 14/01/282 version 1.3
- Conditions
- Osteoarthritis, Knee
- Study type
- Interventional
- Recruitment status
- SuspendedReason stopped: initially stopped recruitment in COVID pandemic, now different prosthesis being use in the Sponsor NHS Trust, unlikely study will restart.
- Enrolment
- 88 participants (estimated)
- Lead sponsor
- Maidstone & Tunbridge Wells NHS TrustUniversity, hospital or other
- Study start
- Jan 2017 (actual)
- Primary completion
- Jul 2027 (estimated)
- Study completion
- Jul 2027 (estimated)
- First posted
- 26 Jun 2015 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Total knee arthroplasty (TKA) is one of the most commonly performed orthopaedic procedures. Approximately 84,000 knee replacement procedures were recorded in the UK in 2012. The main goal of TKA is to relieve the disabling pain of arthritic disease.
Patient satisfaction following TKA is related to quick recovery and return to daily activities. This can be dependent on the design of the implant used in the knee. Improvements in implant design and surgical technique mean many modern designs offer implant survival rates beyond 10 - 15 years.
As cost pressure increases in the NHS the unit cost of implants is now being scrutinised, particularly with regard to cost effectiveness. The Press-Fit Condylar (PFC) Sigma implant can be used with either a conventional metal backed or alternatively an all polyethylene tibial component (part fitted to the shin bone), the latter considerably cheaper to manufacture. Four small prospective randomised trials and one large regional registry study with long follow up support the safe use of all polyethylene tibial components in TKA. The investigators will therefore undertake a prospective randomised controlled trial comparing the results of all polyethylene tibial components with those of conventional metal backed tibial components in patients aged 75 or over, comparing both clinical outcome and radiological survivorship.
The type of knee replacement used for each patient (metal-backed or polyethylene) will be chosen at random once a patient has agreed to take part in the study.
Data will be collected by means of follow-up appointments and questionnaires and clinical tests both before the operation 1 year, 2 years and 5 years postoperatively. This will allow us to see how both types of knee replacement perform over time and if one performs better than the other in terms of patients movement, pain and functional activities.
Detailed description
Summary of design and methodology.
When a patient who is appropriate for the study is added to the waiting list for a Total Knee replacement they will be given (or if missed, posted) an information sheet about the study. This will allow patients several weeks to read the information and telephone the Orthopaedic research department, if they wish, with any questions they may have.
The Patients will then come to preassessment clinic as usual. At this point the study will be explained again in person, the patient will be given time to ask questions and will be asked if they wish to consent to participating.
If the patient consents to taking part they will complete preoperative measures and questionnaires There are 3 questionnaires on how the patient is functioning. 2 are completed by the patient and 1 with the help of the Researcher
The questionnaires are:
Oxford Knee Score American Knee Society Score (AKSS) Medical Outcomes Study Short Form-36 Health Survey (MOS SF-36) All questionnaires will be performed preoperatively, 1 year, 2 years and 5 years postoperatively.
Six weeks postoperatively the patient will attend a follow-up clinic. This is standard for all patients undergoing knee replacement surgery at the Tunbridge Wells Hospital. Routine wound checks and postoperative care will take place and any patient's concerns dealt with. At this point the patient will be booked in for another routine follow up appointment 3 months postoperatively. No study data will be collected at these visits besides adverse events or lost to follow-up where appropriate.
At one year post-operatively the patient will be asked to attend for an appointment. The knee will be assessed clinical and same series of clinician and patient questionnaires completed. A series of x-rays will also be taken to allow the position of the implant to be recorded. Measurements will be taken to be taken from the x-rays Similarly the patient will be invited to attend a further 2 appointments at 2 year and 5 years post-operatively. At these appointments the questionnaires will be repeated along with the x-rays.
Should the patient wish to withdraw at any point they are free to do so and will not then be contacted for any subsequent appointments unless they are due routine clinical appointments .
Any patient undergoing total knee replacement and not in the study will attend routine 6 week and 3 month and one year follow-up appointments, as routine but will be discharged when appropriate and will not be subject to long term follow-up.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| All-polyethylene Tibial component | Active comparator | Device: Sigma PFCSigma PFC All polyethylene Tibial component will be implanted |
| Metal Backed Tibial component | Active comparator | Device: Sigma PFCSigma PFC metal-backed tibial component will be implanted |
Who may qualify
- Ages
- 75 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Older adult
Key inclusion criteria (6 listed)
- Patients suitable for simple cemented primary knee arthroplasty
- Patients presenting with osteoarthritis of the knee
- Patients with inflammatory arthropathy, requiring total knee arthroplasty
- Patients must be ambulatory at time of preoperative assessment clinic
- Patients must be able to understand instructions and be willing to return for follow up
Key exclusion criteria (5 listed)
- Previous knee surgery (except arthroscopic / open meniscectomy)
- Patients with significant medical co-morbidity
- Disorders causing abnormal gait or significant pain
- Patients unable to consent
- Severe visual impairment
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Sigma PFCpatients will receive either an all polyethylene tibial component or a metal- backed component | Device | All-polyethylene Tibial component, Metal Backed Tibial component |
Primary outcome
American Knee Society Score
Time frame: 5 year outcomes
Results and safety
Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 29 Jul 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Paul Gibb principal investigator
Maidstone and Tunbridge Wells NHS trust
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Sigma PFC in people with Osteoarthritis, Knee, run by Maidstone & Tunbridge Wells NHS Trust at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: paused, as of the sponsor's last update on 29 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Results are not available in the source record.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
American Knee Society Score (time frame: 5 year outcomes). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 29 Jul 2026; AzTrials last refreshed its copy on 6 Nov 2026.