OsteoarthritisNCT00175136
A Comparison of the Design of Tibia Stems in Cemented Total Knee Arthroplasty - Wedge Stem Versus I-beam Stem.
A study testing Maxim TKA in people with Osteoarthritis, run by University of Aarhus at 1 site in Denmark.
Trial summary
The purpose of this study is to compare the early migration and periprosthetic bone changes of two cemented total knee arthroplasties with different tibial stem design. Only the tibial prostheses plateau varies in that one is an wedge-shaped stem and the other is a I-shaped stem. Read more about this study
- Who is it for?
- Ages 70 years and older
- Conditions the study is for
- Osteoarthritis
- What is being tested?
- Maxim TKA
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 54 participants
- Where
- 1 siteDenmark
- Study dates
- Jan 2005to Oct 2009
- 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 70 years and older
- All sexes
- No healthy volunteers
- Older adult
Who may be able to join
- Patients with one- or double-sided primary knee arthrosis.
- Patients with a sufficient bone quality for implantation of knee prosthesis.
- Informed and written patient consent.
Who cannot join
- Patients with neuromuscular or vascular diseases in the affected leg.
- Patients who peroperatively are estimated unsuitable for knee arthroplasty e.g. due to bone cysts or dilution of the bone mass.
- Patients who use non-steroid anti-inflammatory drugs (NSAID) and cannot refrain from taking them postoperatively (this includes COX-2-inhibitors).
- Patients with osteoporosis estimated from the preoperative x-ray or former diagnosis of osteoporosis.
- Patients with knee arthrosis following fracture sequelae.
- Women, who are pregnant or are at risk of getting pregnant throughout the 2 year follow-up.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: A Comparison of the Design of Tibia Stems - Wedge Stem Versus I-beam Stem. A Prospective Randomized Migration- and Bone Density Study on Primary Cemented Knee Implants.
The purpose of this study is to compare the early migration and periprosthetic bone changes of two cemented total knee arthroplasties with different tibial stem design. Only the tibial prostheses plateau varies in that one is an wedge-shaped stem and the other is a I-shaped stem.
Read the detailed description
Around 4% of total knee arthroplasties (TKA) are revised 15 years after the primary operation, most due to loosening of the implant. About 70 % TKA are fixed with bone cement and in general the results after total knee arthroplasty are excellent and with the existing technique about 95% well functioning prostheses can be expected 10 years post surgery. The most serious late complication to surgery is aseptic loosening of the implants; and this remains one of the main courses of failure of both uncemented and cemented total knee implants.
Implant design, method of fixation and the bone mass density has a large influence on implant stability. Fixation of the tibia base plates in total knee arthroplasty can be obtained by different designs of anchorage in the tibia e.g. central round stems, fins and pegs. The smaller the tibia stem; the lesser amount of bone is lost at implantation and following revisions rendering probable a time gain before secondary arthrodesis is necessary. The tibia stem cannot be to tiny either because it has to be able to resist the load of shearing forces naturally presented by the knee kinetics.
In this project we are using modularly tibia components with a central wedge- and I-beam shaped stem respectively. Both type of prosthesis are consolidated in the bone by bone cement applied under the base-plate while the stem is fixed press-fit (without cement) in the proximal tibia.
The purpose of this study is to compare the early migration of two cemented total knee implants with different tibial stem design by RSA (radio stereophotogrammetric analysis). Furthermore, we will make research into the periprosthetic bone and it's changes after surgery using DEXA. Finally the extend of the expected micromovements between the polyethylene liner and the metal backing of the titanium plateau will be compared and taken into account with the results.
Tibia wedge stems are exposed to the greatest load test by shearing forces while block stems are bearing the greater load with compression and some scientists therefore speculate that block-designs are better than wedge-designs. This project is set up to explain the theoretical speculations about design and implant survival. The durability of the implants have been tested in account of fatigue and durability in a 80-20 test and they're both able to resist 4-6 times bodyweight. Furthermore, the polyethylene is produced by direct compression molding making it very resistant to wear.
To evaluate both the implant-bone micromotions and the polyethylene-implant micromovements metal markers have been placed on the implant prior to surgery and furthermore into the tibial bone and into the tibial polyethylene intra-operatively allowing us to evaluate stereo x-rays by a photogrammetric computer analyses called RSA at the Orthopaedic Center, Aarhus University Hospital. Follow-up stereo x-rays will be scheduled for 1 week, 3 months, 6 month, 1 years and 2 years post-surgery. Periprostetic bone density will be evaluated at 1 week, 1 year and 2 years upon inclusion at the Orthopaedic Center, Aarhus University Hospital.
- Conditions
- Osteoarthritis
- Being tested
- Maxim TKA
- Keywords
- RSA, DEXA, Gonarthrosis, Knee Arthroplasty, Micromotion of polyethylen liner, Stem arthroplasty design
- Medical subject headings
- Osteoarthritis, Osteoarthritis, Knee
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Maxim TKADevice
Also called Biomet Merck: Maxim TKA
Operation with Total Knee Arthroplasty and either an I-beam stem or a wedge stem of the tibial component.
| Study group | Role | What they receive |
|---|---|---|
| I-beam | Active comparator | I-beam stem design of tibial component for Total Knee Arthroplasty. Receives: Device: Maxim TKA |
| wedge | Active comparator | Wedge stem design of tibial component for Total Knee Arthroplasty. Receives: Device: Maxim TKA |
What is being measured
The primary outcome is the main question the study is designed to answer.
Tibial component migration evaluated by RSA.
Measured: post-operative, three months, six months, one year, two years
Periprosthetic bone changes evaluated by DEXA.
Measured: post-operative, one year, two years
Secondary outcomes (1)
Micromotion of the modular polyethylene liner in both type prostheses evaluated by RSA.
Measured: post-operative, three months, six months, one year, two years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Sep 2005 (estimated)
- Study startJan 2005
- Primary completionOct 2009
- Study completionOct 2009
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for OsteoarthritisStudies of the same condition, open and under way.
- More trials run by University of AarhusThe sponsor's other registered studies.
- 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
- Participant
- Enrolment
- 54 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Aarhus
- Sponsor type
- University, hospital or other
- Collaborators
- Aarhus University Hospital
- Responsible party
- Sponsor
- Investigators
- Kjeld Søballe, MD, Prof., Principal investigator, Orthopaedic Center, Aarhus University Hospital, Tage-Hansens Gade 2, 8000 Aarhus C, Denmark.
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00175136
- Sponsor's protocol ID
- 20030239
- Status last verified
- Oct 2010
- First submitted
- 10 Sep 2005
- Last updated
- 4 Jan 2023
- Results posted
- No
- Data monitoring committee
- No
Study at a glance
From the registry record, last updated by the sponsor on 4 Jan 2023. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Comparison of the Design of Tibia Stems - Wedge Stem Versus I-beam Stem. A Prospective Randomized Migration- and Bone Density Study on Primary Cemented Knee Implants.
- ClinicalTrials.gov ID
- NCT00175136
- Acronym / sponsor ID
- 20030239
- Conditions
- Osteoarthritis
- Keywords
- RSA, DEXA, Gonarthrosis, Knee Arthroplasty, Micromotion of polyethylen liner, Stem arthroplasty design
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 54 participants (actual)
- Lead sponsor
- University of AarhusUniversity, hospital or other
- Collaborators
- Aarhus University Hospital
- Study start
- Jan 2005
- Primary completion
- Oct 2009 (actual)
- Study completion
- Oct 2009 (actual)
- First posted
- 15 Sep 2005 (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.
The purpose of this study is to compare the early migration and periprosthetic bone changes of two cemented total knee arthroplasties with different tibial stem design. Only the tibial prostheses plateau varies in that one is an wedge-shaped stem and the other is a I-shaped stem.
Detailed description
Around 4% of total knee arthroplasties (TKA) are revised 15 years after the primary operation, most due to loosening of the implant. About 70 % TKA are fixed with bone cement and in general the results after total knee arthroplasty are excellent and with the existing technique about 95% well functioning prostheses can be expected 10 years post surgery. The most serious late complication to surgery is aseptic loosening of the implants; and this remains one of the main courses of failure of both uncemented and cemented total knee implants.
Implant design, method of fixation and the bone mass density has a large influence on implant stability. Fixation of the tibia base plates in total knee arthroplasty can be obtained by different designs of anchorage in the tibia e.g. central round stems, fins and pegs. The smaller the tibia stem; the lesser amount of bone is lost at implantation and following revisions rendering probable a time gain before secondary arthrodesis is necessary. The tibia stem cannot be to tiny either because it has to be able to resist the load of shearing forces naturally presented by the knee kinetics.
In this project we are using modularly tibia components with a central wedge- and I-beam shaped stem respectively. Both type of prosthesis are consolidated in the bone by bone cement applied under the base-plate while the stem is fixed press-fit (without cement) in the proximal tibia.
The purpose of this study is to compare the early migration of two cemented total knee implants with different tibial stem design by RSA (radio stereophotogrammetric analysis). Furthermore, we will make research into the periprosthetic bone and it's changes after surgery using DEXA. Finally the extend of the expected micromovements between the polyethylene liner and the metal backing of the titanium plateau will be compared and taken into account with the results.
Tibia wedge stems are exposed to the greatest load test by shearing forces while block stems are bearing the greater load with compression and some scientists therefore speculate that block-designs are better than wedge-designs. This project is set up to explain the theoretical speculations about design and implant survival. The durability of the implants have been tested in account of fatigue and durability in a 80-20 test and they're both able to resist 4-6 times bodyweight. Furthermore, the polyethylene is produced by direct compression molding making it very resistant to wear.
To evaluate both the implant-bone micromotions and the polyethylene-implant micromovements metal markers have been placed on the implant prior to surgery and furthermore into the tibial bone and into the tibial polyethylene intra-operatively allowing us to evaluate stereo x-rays by a photogrammetric computer analyses called RSA at the Orthopaedic Center, Aarhus University Hospital. Follow-up stereo x-rays will be scheduled for 1 week, 3 months, 6 month, 1 years and 2 years post-surgery. Periprostetic bone density will be evaluated at 1 week, 1 year and 2 years upon inclusion at the Orthopaedic Center, Aarhus University Hospital.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (participant)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| I-beam | Active comparator | Device: Maxim TKAI-beam stem design of tibial component for Total Knee Arthroplasty. |
| wedge | Active comparator | Device: Maxim TKAWedge stem design of tibial component for Total Knee Arthroplasty. |
Who may qualify
- Ages
- 70 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Older adult
Key inclusion criteria (3 listed)
- Patients with one- or double-sided primary knee arthrosis.
- Patients with a sufficient bone quality for implantation of knee prosthesis.
- Informed and written patient consent.
Key exclusion criteria (6 listed)
- Patients with neuromuscular or vascular diseases in the affected leg.
- Patients who peroperatively are estimated unsuitable for knee arthroplasty e.g. due to bone cysts or dilution of the bone mass.
- Patients who use non-steroid anti-inflammatory drugs (NSAID) and cannot refrain from taking them postoperatively (this includes COX-2-inhibitors).
- Patients with osteoporosis estimated from the preoperative x-ray or former diagnosis of osteoporosis.
- Patients with knee arthrosis following fracture sequelae.
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 |
|---|---|---|
| Maxim TKAAlso: Biomet Merck: Maxim TKAOperation with Total Knee Arthroplasty and either an I-beam stem or a wedge stem of the tibial component. | Device | I-beam, wedge |
Primary outcome
Tibial component migration evaluated by RSA.
Time frame: post-operative, three months, six months, one year, two years
Periprosthetic bone changes evaluated by DEXA.
Time frame: post-operative, one year, two years
1 secondary outcome
Micromotion of the modular polyethylene liner in both type prostheses evaluated by RSA.
Time frame: post-operative, three months, six months, one year, two years
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 4 Jan 2023.
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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.
Kjeld Søballe, MD, Prof. principal investigator
Orthopaedic Center, Aarhus University Hospital, Tage-Hansens Gade 2, 8000 Aarhus C, Denmark.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Maxim TKA in people with Osteoarthritis, run by University of Aarhus at 1 site in Denmark.
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 3 inclusion and 6 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: finished, as of the sponsor's last update on 4 Jan 2023. 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 Denmark. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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?
Tibial component migration evaluated by RSA. (time frame: post-operative, three months, six months, one year, two years). The study lists 2 primary outcomes in all. 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 4 Jan 2023.