An interventional study of TKA in Knee Osteoarthritis, sponsored by Helse Møre og Romsdal HF. Active, not recruiting at 1 site in Norway. Open to participants aged 50 Years to 75 Years. Per ClinicalTrials.gov, last updated 2026-08-17.
Sponsored by Helse Møre og Romsdal HF · Not applicable, Interventional, and Treatment
The goal of this randomized controlled trial is to analyze the stability of a cementless Total Knee Arthroplasty (TKA) over time and compare it to a well-documented implant in patients with knee osteoarthritis. The main aim is to answer if there is a difference in stability over time as a measure of long time survivorship in these 2 implants.
50 participants will be randomly allocated to receive either the Triathlon Tritanium (Stryker) or the Global Medacta Knee Sphere (GMK Sphere, Medacta) 3D printed cementless TKAs.
Total joint replacement is an efficacious treatment for osteoarthritis of hips and knees. Both TKA and Total Hip Artrhoplasties (THA) have excellent implant survivorship. However, patients' satisfaction is lower in TKA than THA. A possible cause of the discrepancy is the unnatural knee kinematics after TKA. Various implants designs have been developed to solve the problem. The most common fixation mode is cemented TKA with good survival up to 15 years. However, newer series in younger patients also have shown lasting survival with cementless implants (Nilsson KG, Prudhon JL). Among various different designs, the medially stabilized total knee, which are designed to reproduce natural knee kinematics with a medial ball-in-socked design, is a promising implant design (No authors listed). Dynamically the medial pivot knee performs more naturally (Bragonzoni L,Petersen ET) compared to other designs. Most data for this design is available only for the cemented version. Up to now there is no safety study performed that confirms the stability over time for this implant with cementless fixation.
In this study, the investigators will therefore analyze the in vivo stability of an uncemented TKA with a medially stabilized design, and compare it with a well-documented comparable implant. In order to do this, the investigators will use the CT based micromotion analysis (Broden C, Broden C). This study will contribute to the understanding of fixation and lead to safety to the patient.
3,302 studies on the registry are indexed under Osteoarthritis, Knee; 608 are open to participants now.
This study's enrollment of 50 is below the median of 70 across 2,731 interventional studies indexed under Osteoarthritis, Knee.
Browse Osteoarthritis, Knee studies →Helse Møre og Romsdal HF is the lead sponsor of 24 studies on the registry; 7 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
Cementless Triathlon Tritanium 3D printed TKA
Procedure: TKA
GMK Sphere cementless 3D printed TKA
Procedure: TKA
Total knee artroplasty with medial parapatellar incision and mechanical alignment without navigation
CTMA Maximum Total Translation
The highest total translation on the implant at each time point
Time frame: Up to 2 years
CTMA Maximum Total Translation
The highest total translation on the implant at each time point
Time frame: Up to 5 years
CTMA Total rotation
Center of mass and peripheral points (degrees)
Time frame: Up to 2 years
CTMA Total rotation
Center of mass and peripheral points (degrees)
Time frame: Up to 5 years
CTMA Total translation
Center of mass and peripheral points (millimeters)
Time frame: Up to 2 years
CTMA Total translation
Center of mass and peripheral points (millimeters)
Time frame: Up to 5 years
The Forgotten Joint Score (FJS)
Patient Reported Outcome Measure PROMs). 12 item likert scale with scores from 0-4 (0=never, 4= allways). Mean value is multiplied with 25 and the subtracted from 100. Maximum score i 100 (excellent), minimum score is 0 (worse).
Time frame: Up to 2 years
The Forgotten Joint Score (FJS)
Patient Reported Outcome Measure PROMs). 12 item likert scale with scores from 0-4 (0=never, 4= allways). Mean value is multiplied with 25 and the subtracted from 100. Maximum score i 100 (excellent), minimum score is 0 (worse).
Time frame: Up to 5 years
The Knee injury and Osteoarthritis Outcome Score (KOOS)
Patient Reported Outcome Measure (PROMs). KOOS consists of 5 subscales; Pain, other Symptoms, Activites of Daily Living (ADL), Sport and Recreation Function (Sport/Rec) and knee-related Quality of Life (QOL). The previous week is the time period considered when answering the questions. Standardized answer options are given (5 Likert boxes) and each question is assigned a score from 0 to 4. A normalized score (100 indicating no symptoms and 0 indicating extreme symptoms) is calculated for each subscale
Time frame: Up to 2 years
The Knee injury and Osteoarthritis Outcome Score (KOOS)
Patient Reported Outcome Measure (PROMs). KOOS consists of 5 subscales; Pain, other Symptoms, Activites of Daily Living (ADL), Sport and Recreation Function (Sport/Rec) and knee-related Quality of Life (QOL). The previous week is the time period considered when answering the questions. Standardized answer options are given (5 Likert boxes) and each question is assigned a score from 0 to 4. A normalized score (100 indicating no symptoms and 0 indicating extreme symptoms) is calculated for each subscale
Time frame: Up to 5 years
Range of motion
From full extension to full flexion (degrees)
Time frame: Up to 2 years
Range of motion
From full extension to full flexion (degrees)
Time frame: Up to 5 years
HKA
Hip knee ankle angle measured on X-ray (degrees). Deviation from 0 is either varus (-) or valgus (+)
Time frame: Up to 2 years
HKA
Hip knee ankle angle measured on X-ray (degrees). Deviation from 0 is either varus (-) or valgus (+)
Time frame: Up to 5 years
BMI
Body mass index (kg/m2)
Time frame: Preoperative
Operation time
Time used in minutes from skin incision to wound closure.
Time frame: Intraoperative
Axial alignment of the tibia
Measured by Bergers method (degrees internal or extarnal rotation)
Time frame: Up to 1 week postoperative
Plan to share: Yes — Individual participant data that underlie the results reported in this article, after deidentification
Supporting information: Study protocol, Sap, Csr
This study is active, not recruiting, as verified in Aug 2026. You cannot join it, but the record below documents what was studied.
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Helse Møre og Romsdal HF