Condition category
Musculoskeletal Diseases
Date applied
22/09/2014
Date assigned
26/11/2014
Last edited
07/09/2015
Prospective/Retrospective
Retrospectively registered
Overall trial status
Ongoing
Recruitment status
No longer recruiting

Plain English Summary

Background and study aims
Metal-backed total knee replacements are the most commonly used total knee replacements all over the world. However, knee replacements with all-polyethylene tibial components remain an attractive alternative as they are cheaper and avoid problems such as the knee joint mechanism locking and some wear and tear issues. Here, we want to compare two types of total knee replacements – the Triathlon PS Knee System with all-polyethylene tibial components and the Triathlon PS Knee System with metal-backed modular tibial components.

Who can participate?
Adults aged 40 to 75 who need a total knee replacement.

What does the study involve?
Participants are randomly allocated to one of two groups. Those in group 1 receive the all-polyethylene tibial components for their total knee replacement. Those in group 2 receive the metal-backed modular tibial components for their total knee replacement. The two types of knee replacements are then compared using RSA (radiostereometric analysis) X rays. This is a special technique that takes two X-rays of the joint from different angles at the same time. This creates a 3D image that can be viewed. During surgery, tiny beads are placed in the bone that will surround the knee replacement. These beads are then used to check the positioning of the knee replacement and whether that changes over time. Each patient taking part in the study is invited to a number of follow up visits – one before being discharged from hospital, one 3 months after surgery, and then at 1, 2, 5, 7 and 10 years after surgery. During these visits, they are asked to complete questionnaires about their health, their activities and their knee. RSA X-rays are also taken.

What are the possible benefits and risks of participating?
The study will help increase knowledge of the two knee replacement systems used in the study.

Where is the study run?
Hässleholms sjukhus, Hässleholm (Sweden)

When is the study starting and how long is it expected to run for?
October 2014 to December 2025.

Who is funding the study?
Stryker SA (Switzerland)

Who is the main contact?
Christina Silver
christina.silver@stryker.com

Trial website

Contact information

Type

Scientific

Primary contact

Dr Sören Toksvig-Larsen

ORCID ID

Contact details

Department of Orthopaedics Hässleholm-Kristianstad-Ystad
Hässleholm Hospital
Hässleholm
281 38
Sweden

Type

Public

Additional contact

Mrs Christina Silver

ORCID ID

Contact details

Stryker SA
Krusegatan 19
Malmö
202 14
Sweden
+46 (0)709 928119
christina.silver@stryker.com

Additional identifiers

EudraCT number

ClinicalTrials.gov number

Protocol/serial number

K-S-046

Study information

Scientific title

Migration and survival of all-polyethylene tibial components compared to the metal-backed modular components of the Triathlon PS Total Knee System. A RSA study

Acronym

N/A

Study hypothesis

1. The primary objective is the assessment of prosthetic migration results after two years with the Triathlon PS Knee System with all-polyethylene tibial components compared to the Triathlon PS Knee System with metal-backed modular components by means of Roentgen Stereophotogrammetry.
2. The secondary objective will be the prediction of the long-term survival based on the two-year migration patterns combined with clinical factors and radiographic aspects. In order to identify other clinical parameters besides the fixation of the prosthesis components, clinical scores and radiographic aspects will be correlated with the RSA outcome.

07/09/2015: Updated recruitment end date from 31/12/2025 to 30/04/2015.

Ethics approval

The Regional Ethical Review Board in Lund, Sweden, 02/09/2014, ref. Dnr 2014/513

Study design

Single-center randomized controlled trial

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 to request a patient information sheet

Condition

Osteoarthritis

Intervention

Patients are informed and screened pre-operative. Patients that comply with the inclusion/exclusion criteria and who give their consent for participation will be given a study ID. After signing Informed Consent, the patients will be randomized in one of the two groups, the day before surgery. The patient will receive either the all-polyethylene tibial component or the metal backed modular tibial component for their Triathlon PS total knee. The principal investigator and the participating surgeons may dissent from the randomization scheme based on intra-operative findings. This patient will be excluded from the study. Follow-up visits are performed at the following time points: prior to discharge, 3 months, 1, 2, 5, 7 and 10 years after surgery. During these visits clinical evaluation and x-rays are done, any adverse events are monitored (if applicable) and the KOOS, EQ-5D and FJS questionnaires are completed by the patient.

Intervention type

Device

Phase

Drug names

Primary outcome measures

The primary outcome measure will be prosthetic migration after two years of the Triathlon PS Knee System with all-polyethylene tibial components and the Triathlon PS Knee System with metal backed modular components by means of Roentgen Stereophotogrammetry.
It is hypothesized that there will be no difference between groups. The difference in migration between components must not exceed 0.3 mm for translations and 0.25° for the rotations to determine equivalence

Secondary outcome measures

The secondary outcome measure will be long-term survival based on the two-year migration patterns combined with clinical factors and radiographic aspects. In order to identify other clinical parameters besides the fixation of the prosthesis components, clinical scores and radiographic aspects will be correlated with the RSA outcome. The 10 years results will be used to verify the predicted long-term survival results.

Overall trial start date

10/09/2014

Overall trial end date

31/12/2025

Reason abandoned

Eligibility

Participant inclusion criteria

1. Patient is able to understand the meaning of the study and is willing to sign the EC approved, study specific Informed Patient Consent Form
2. Patients with a pre-operative knee score of < 70
3. Patients scheduled to undergo primary total knee replacement with any of the following indication
3.1. Painful and disabled knee joint resulting from osteoarthritis
3.2. One or more compartments are involved
4. No indication for Triathlon PS
5. Need to obtain pain relief and improve function
6. Ability and willingness to follow instructions, including control of weight and activity level, and to return for follow-up evaluations
7. A good nutritional state of the patient
8. The subject is a male or non-pregnant female between 40 and 75 years of age

Participant type

Patient

Age group

Adult

Gender

Both

Target number of participants

60

Participant exclusion criteria

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

Recruitment start date

10/09/2014

Recruitment end date

30/04/2015

Locations

Countries of recruitment

Sweden

Trial participating centre

Department of Orthopaedics Hässleholm-Kristianstad-Ystad
Hässleholm Hospital
Hässleholm
281 38
Sweden

Sponsor information

Organisation

Stryker SA

Sponsor details

Cité-Centre
Grand-Rue 92
Montreux
1820
Switzerland

Sponsor type

Industry

Website

Funders

Funder type

Industry

Funder name

Stryker SA (Switzerland)

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