Knee implant showdown: which design stays put?
NCT ID NCT04358575
First seen Jun 26, 2026 · Last updated Jun 26, 2026
Summary
This study looked at two different designs of knee replacement implants in 60 people with arthritis. The goal was to see how much each implant moved inside the bone over two years using a special X-ray technique called RSA. The findings could help surgeons pick the better implant for long-term stability.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- Triathlon CS Knee System (all-polyethylene tibial component vs. metal-backed modular component)
- What this could lead to
- If successful, this could help doctors choose which knee implant design lasts longer and moves less, improving long-term outcomes for arthritis patients.
- What could go wrong
- This is a small, completed study with only 60 participants, so results may not apply to everyone. It measures implant movement, not directly patient pain or function.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
-
Not a phased trial
Phase numbers describe drug development. The registry uses this when they do not apply, as it does for trials of devices, procedures or behaviour changes, and for observational studies.
- Participants
-
60 people
The number who actually took part.
- Started
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Feb 2014
- Finished
-
Apr 2025
- Lead sponsor
-
Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
-
40 to 75 years
- Sex
-
Anyone
- Healthy volunteers
-
Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
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Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
1\. The subject is morbidly obese, defined as Body Mass Index (BMI) of \> 40. 2. Patient has a flexion contracture of 15° and more. 3. Patient has a varus/valgus contracture of 15° and more. 4. Patients with a pre-operative knee score of \>70. 5. The subject has a history of total or unicompartmental reconstruction of the affected joint. 6. The subject will be operated bilaterally. 7. Patients who had a Total Hip Arthroplasty (THA) on contralateral and/or ipsilateral side within the last year that is considered to have an unsatisfactory outcome (Patients with contralateral and/or ipsilateral THA \> 1 year ago with good outcome can be included in the study). 8. Patients who had a Total Knee Arthroplasty (TKA) on contralateral side within the last 6 months that is considered to have an unsatisfactory outcome. (Patients with contralateral TKA \> 6 months ago with good outcome can be included in the study). 9. The subject has an active or suspected latent infection in or about the knee joint. 10. Osteomyelitis 11. Sepsis 12. Patient who is expected to need lower limb joint replacement for another joint within one year. 13. The subject has a neuromuscular or neurosensory deficiency, which would limit the ability to assess the performance of the device. 14. The subject has a systemic or metabolic disorder leading to progressive bone deterioration. 15. The subject is immunologically suppressed or receiving steroids in excess of normal physiological requirements. 16. The subject's bone stock in compromised by disease or infection which cannot provide adequate support and/or fixation to the prosthesis. 17. The subject has had a knee fusion to the affected joint. 18. Female patients planning a pregnancy during the course of the study. 19. The patient is unable or unwilling to sign the Informed Consent specific to this study
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
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