Knee OsteoarthritisNCT02861794
Stability of Contemporary Knee Arthroplasty
A study testing Medacta International, GMK Sphere medially stabilized knee in people with Knee Osteoarthritis, run by Oslo University Hospital at 1 site in Norway.
Trial summary
Total joint replacement is an efficacious treatment for osteoarthritis of hips and knees. Both total knee replacement (TKR) and total hip replacements (THR) have excellent implant survivorship. However, patient satisfaction is lower in TKR than THR. Read more about this study
- Who is it for?
- Ages 50 to 75 years
- Conditions the study is for
- Knee Osteoarthritis
- What is being tested?
- Medacta International, GMK Sphere medially stabilized knee
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 44 participants
- Where
- 1 siteNorway
- Study dates
- 1 May 2016to 31 Dec 2024
- 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 50 to 75 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Patients with knee osteoarthritis
Who cannot join
- Preoperative severe deformity (Femoro-tibial angle < 175°or > 190°measured on a full-length leg image at weight bearing)
- Preoperative flexion contracture more than 15°
- Preoperative limited range of motion under anesthetics (less than 110°)
- Less than 50 or more than 75 years of age at the time of surgery
- Use of walking aids because of other musculoskeletal and neuromuscular problems
- Preoperative diagnosis other than osteoarthritis and avascular necrosis (e.g. rheumatoid arthritis, tumors)
Show all 11Show fewer
- Revision arthroplasty
- Obesity with BMI >35
- Impaired collateral ligaments
- Malposition of femoral and tibial implants (Internally rotated or more than 10° externally rotated implants will be excluded. The rotation of femoral implant is measured on postoperative CT images in reference to surgical epicondylar line. The rotation of tibial implant is determined according to Berger's measurement)
- Postoperative revision surgery due to deep wound infection
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Evaluation of Early Migration of Medially Stabilized Arthroplasty as a Predictor of Long Time Survivorship (Implant Design Study)
Total joint replacement is an efficacious treatment for osteoarthritis of hips and knees. Both total knee replacement (TKR) and total hip replacements (THR) have excellent implant survivorship. However, patient satisfaction is lower in TKR than THR. A possible cause of the discrepancy is the unnatural knee kinematics after TKR. Various implants designs have been developed to solve the problem. However, most of their designs are based on experimental data and little has been studied about their actual performance in vivo. In this study, the investigators will analyze the in vivo stability of the Global Medacta Knee Sphere (GMK Sphere) implant. Migration of the implants will be monitored with a high precision measuring method called Radiostereometric Analysis (RSA). The investigators assume the investigators study will contribute the development of more satisfying knee implants.
Read the detailed description
Worldwide the number of patients requiring treatment for osteoarthritis is increasing due to increasing obesity, an ageing population and a high demanding younger population. Learmonth describes hip arthroplasty as the "operation of the century" because patients are highly satisfied with pain relief and function after the procedure. Knee arthroplasties have in recent years also shown promising results and have surpassed hip arthroplasty in frequency in western countries. However, patient satisfaction is not as high. Reported problems are insufficient function and persistent pain. On the other hand, knee arthroplasties are increasingly implanted in younger and more active patients who require high function and quality of life. Improvement of knee implants is an urgent issue in the field of orthopaedic research.
Knee Kinematics and implant designs
A possible cause of lower function of replaced knees is the unnatural postoperative knee kinematics. Kinematics of replaced knees is closely related to their function. Studies show that replaced knees with excellent flexion angles have kinematic similarities to normal knees and malalignments of implants can cause postoperative pain.
Compared to hip joints which are simple ball-and socket joints, the kinematics of knee joints is more complex. The kinematics are a combination of a rolling and gliding motion of the femoral condyles and rotation of the tibia. Based on the kinematics of the normal knee joint, various attempts have been made on the design of knee implants to reconstruct normal kinematics after replacement surgery. All of these implants have satisfying survivorship, but unicondylar arthroplasty which retains both cruciate ligaments has the best clinical results with survivorship at 15 years 93%. In total knee replacement (TKR) the Anterior Cruciate Ligament (ACL) and possibly the Posterior Cruciate Ligament (PCL) are sacrified. When sacrificing the one or both of the cruciate ligaments, natural knee kinematics are affected. The function of the cruciate ligaments can be mimicked by different designs of the tibial insert.
The most used knee implant in Norway, the NexGen Cruciate-retaining (CR) implant design, does not retain the ACL and does not mimic natural knee kinematics. The tibial insert of the medial pivot implant design (GMK Sphere) has a constrained medial ball in socket joint and at the same time allows lateral anterioposterior movement. This new design was developed by a group of dedicated researchers. The design intention is to resemble the function of the cruciate ligaments and at the same time allow for lateral anterioposterior movement (rollback).
Small alterations in implant design can influence the survival of implants. The final design of the GMK Sphere was introduced in 2012. New implants should be monitored and assessed in small, controlled trials with high precision measuring methods.
Analytical Method
RSA has been used in orthopedic research fields since 1970s. The original application of this method was for the evaluation of implant migration (i.e. fixation) and polyethylene wear of artificial joints using static X-ray pictures. Clinically relevant association between early migration of tibial implants detected by RSA and late revision for loosening has been reported. Also, attempts to measure in vivo polyethylene wear have been reported using RSA.
Purpose of this study
The aim of this study is to analyse the in vivo performance (e.g. stability) of a medially stabilized knee arthroplasty implant (Medacta International, GMK Sphere) using static RSA method over a period of 5 years. 2-year results have already been analysed and are inconclusive in regards to migration as the implant is apparently stable, but shows greater than anticipated movement. Mid-term follow-up (5-year) is therefore essential to evaluate migration of this implant. We therefore wish to obtain 5-year follow-ups of these patients.
Additionally, the investigators will analyse the wear in the ball and socket (medial) side of the tibiofemoral articulation.
30 patients will go through stability and wear testing with static RSA.
This study will contribute to the safety for patients with this new implant by providing basic knowledge of this knee arthroplasty and promoting further development of knee implant designs.
- Conditions
- Knee Osteoarthritis
- Being tested
- Medacta International, GMK Sphere medially stabilized knee
- Keywords
- Total Knee Arthroplasty (TKA), Total Knee Replacement (TKR), Kinematics, RSA, Knee arthroplasty, Implant stability, Migration, Wear, Medial pivot
- Medical subject headings
- Osteoarthritis, Knee
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Medacta International, GMK Sphere medially stabilized kneeProcedure or surgery
Total Knee Replacement
| Study group | Role | What they receive |
|---|---|---|
| GMK Sphere | Other | Patients receive a GMK Sphere Total Knee Replacement. Receives: Procedure: Medacta International, GMK Sphere medially stabilized knee |
What is being measured
The primary outcome is the main question the study is designed to answer.
Stability of the GMK Sphere prosthesis measured by Radiostereometric Analysis (RSA)
Stability of the implant is measured in mm after 5 years (Maximum Total Point Motion in mm, MTPM)
Measured: 5 years
Secondary outcomes (7)
Knee Society Score (KSS)
Patient reported outcome measures
Measured: 5 years
Forgotten Joint Score 12 (FJS-12)
Patient reported outcome measures
Measured: 5 years
Knee injury and Osteoarthritis Outcome Score (KOOS)
Patient reported outcome measures
Measured: 5 years
Range of motion (ROM)
Clinical measurement using goniometer
Measured: 5 years
Hip-knee-ankle angle (HKA-angle)
The axis of the lower extremity after knee arthroplasty
Measured: 5 years
CT-rotation of implants
Evaluation of tibia implant rotation using Berger's method
Measured: 5 years
Stability of the GMK Sphere prosthesis
Stability of the implant is measured in mm and degrees after 5 years using RSA (translation and rotasjon for x, y and z)
Measured: 5 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted10 Aug 2016 (estimated)
- Study start1 May 2016
- Primary completion31 Dec 2024
- Study completion31 Dec 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (28)Papers the sponsor has linked to this study.
- Other trials for Knee OsteoarthritisStudies of the same condition, open and under way.
- More trials run by Oslo University HospitalThe 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
- Not applicable
- Intervention model
- Single group
- Model description
- Prospective interventional single group cohort study of a cemented medial pivot knee implant, using the diagnostic method of RSA.
- Masking
- None (open label)
- Enrolment
- 44 participants (actual)
Sponsor and investigators
- Lead sponsor
- Oslo University Hospital
- Sponsor type
- University, hospital or other
- Collaborators
- Helse More and Romsdal Trust, Medacta International SA
- Responsible party
- Principal investigator, Stephan M Rohrl, Oslo University Hospital
- Investigators
- Stephan Maximillian Røhrl, MD, PhD, Study director, Center for Implant and Radiostereometric Research Oslo (CIRRO)Frank-David Oehrn, MD, Principal investigator, Kristiansund Hospital, Helse More and Romsdal TrustLars Harald William Engseth, MD, PhD, Principal investigator, Center for Implant and Radiostereometric Research Oslo (CIRRO)
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02861794
- Sponsor's protocol ID
- 424444-1
- Status last verified
- Nov 2025
- First submitted
- 28 Apr 2016
- Last updated
- 25 Nov 2025
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Kurtz S, Ong K, Lau E, Mowat F, Halpern M. Projections of primary and revision hip and knee arthroplasty in the United States from 2005 to 2030. J Bone Joint Surg Am. 2007 Apr;89(4):780-5. doi: 10.2106/JBJS.F.00222.
PubMed 17403800Kurtz SM, Lau E, Ong K, Zhao K, Kelly M, Bozic KJ. Future young patient demand for primary and revision joint replacement: national projections from 2010 to 2030. Clin Orthop Relat Res. 2009 Oct;467(10):2606-12. doi: 10.1007/s11999-009-0834-6. Epub 2009 Apr 10.
PubMed 19360453Learmonth ID, Young C, Rorabeck C. The operation of the century: total hip replacement. Lancet. 2007 Oct 27;370(9597):1508-19. doi: 10.1016/S0140-6736(07)60457-7.
PubMed 17964352Dieppe P, Lim K, Lohmander S. Who should have knee joint replacement surgery for osteoarthritis? Int J Rheum Dis. 2011 May;14(2):175-80. doi: 10.1111/j.1756-185X.2011.01611.x.
PubMed 21518317Carr AJ, Robertsson O, Graves S, Price AJ, Arden NK, Judge A, Beard DJ. Knee replacement. Lancet. 2012 Apr 7;379(9823):1331-40. doi: 10.1016/S0140-6736(11)60752-6. Epub 2012 Mar 6.
PubMed 22398175Hawker GA, Badley EM, Borkhoff CM, Croxford R, Davis AM, Dunn S, Gignac MA, Jaglal SB, Kreder HJ, Sale JE. Which patients are most likely to benefit from total joint arthroplasty? Arthritis Rheum. 2013 May;65(5):1243-52. doi: 10.1002/art.37901.
PubMed 23459843Wylde V, Jeffery A, Dieppe P, Gooberman-Hill R. The assessment of persistent pain after joint replacement. Osteoarthritis Cartilage. 2012 Feb;20(2):102-5. doi: 10.1016/j.joca.2011.11.011. Epub 2011 Nov 30.
PubMed 22178464Ravi B, Croxford R, Reichmann WM, Losina E, Katz JN, Hawker GA. The changing demographics of total joint arthroplasty recipients in the United States and Ontario from 2001 to 2007. Best Pract Res Clin Rheumatol. 2012 Oct;26(5):637-47. doi: 10.1016/j.berh.2012.07.014.
PubMed 23218428Ibrahim T, Bloch B, Esler CN, Abrams KR, Harper WM. Temporal trends in primary total hip and knee arthroplasty surgery: results from a UK regional joint register, 1991-2004. Ann R Coll Surg Engl. 2010 Apr;92(3):231-5. doi: 10.1308/003588410X12628812458572. Epub 2010 Mar 10.
PubMed 20223054Watanabe T, Ishizuki M, Muneta T, Banks SA. Knee kinematics in anterior cruciate ligament-substituting arthroplasty with or without the posterior cruciate ligament. J Arthroplasty. 2013 Apr;28(4):548-52. doi: 10.1016/j.arth.2012.06.030. Epub 2012 Oct 31.
PubMed 23122654Bell SW, Young P, Drury C, Smith J, Anthony I, Jones B, Blyth M, McLean A. Component rotational alignment in unexplained painful primary total knee arthroplasty. Knee. 2014 Jan;21(1):272-7. doi: 10.1016/j.knee.2012.09.011. Epub 2012 Nov 7.
PubMed 23140906Smith PN, Refshauge KM, Scarvell JM. Development of the concepts of knee kinematics. Arch Phys Med Rehabil. 2003 Dec;84(12):1895-902. doi: 10.1016/s0003-9993(03)00281-8.
PubMed 14669200Chalidis BE, Sachinis NP, Papadopoulos P, Petsatodis E, Christodoulou AG, Petsatodis G. Long-term results of posterior-cruciate-retaining Genesis I total knee arthroplasty. J Orthop Sci. 2011 Nov;16(6):726-31. doi: 10.1007/s00776-011-0152-1. Epub 2011 Sep 10.
PubMed 21909722Font-Rodriguez DE, Scuderi GR, Insall JN. Survivorship of cemented total knee arthroplasty. Clin Orthop Relat Res. 1997 Dec;(345):79-86.
PubMed 9418624Sabouret P, Lavoie F, Cloutier JM. Total knee replacement with retention of both cruciate ligaments: a 22-year follow-up study. Bone Joint J. 2013 Jul;95-B(7):917-22. doi: 10.1302/0301-620X.95B7.30904.
PubMed 23814243
Study at a glance
From the registry record, last updated by the sponsor on 25 Nov 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluation of Early Migration of Medially Stabilized Arthroplasty as a Predictor of Long Time Survivorship (Implant Design Study)
- ClinicalTrials.gov ID
- NCT02861794
- Acronym / sponsor ID
- 424444-1
- Conditions
- Knee Osteoarthritis
- Keywords
- Total Knee Arthroplasty (TKA), Total Knee Replacement (TKR), Kinematics, RSA, Knee arthroplasty, Implant stability, Migration, Wear
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 44 participants (actual)
- Lead sponsor
- Oslo University HospitalUniversity, hospital or other
- Collaborators
- Helse More and Romsdal Trust, Medacta International SA
- Study start
- 1 May 2016 (actual)
- Primary completion
- 31 Dec 2024 (actual)
- Study completion
- 31 Dec 2024 (actual)
- First posted
- 10 Aug 2016 (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 joint replacement is an efficacious treatment for osteoarthritis of hips and knees. Both total knee replacement (TKR) and total hip replacements (THR) have excellent implant survivorship. However, patient satisfaction is lower in TKR than THR. A possible cause of the discrepancy is the unnatural knee kinematics after TKR. Various implants designs have been developed to solve the problem. However, most of their designs are based on experimental data and little has been studied about their actual performance in vivo. In this study, the investigators will analyze the in vivo stability of the Global Medacta Knee Sphere (GMK Sphere) implant. Migration of the implants will be monitored with a high precision measuring method called Radiostereometric Analysis (RSA). The investigators assume the investigators study will contribute the development of more satisfying knee implants.
Detailed description
Worldwide the number of patients requiring treatment for osteoarthritis is increasing due to increasing obesity, an ageing population and a high demanding younger population. Learmonth describes hip arthroplasty as the "operation of the century" because patients are highly satisfied with pain relief and function after the procedure. Knee arthroplasties have in recent years also shown promising results and have surpassed hip arthroplasty in frequency in western countries. However, patient satisfaction is not as high. Reported problems are insufficient function and persistent pain. On the other hand, knee arthroplasties are increasingly implanted in younger and more active patients who require high function and quality of life. Improvement of knee implants is an urgent issue in the field of orthopaedic research.
Knee Kinematics and implant designs
A possible cause of lower function of replaced knees is the unnatural postoperative knee kinematics. Kinematics of replaced knees is closely related to their function. Studies show that replaced knees with excellent flexion angles have kinematic similarities to normal knees and malalignments of implants can cause postoperative pain.
Compared to hip joints which are simple ball-and socket joints, the kinematics of knee joints is more complex. The kinematics are a combination of a rolling and gliding motion of the femoral condyles and rotation of the tibia. Based on the kinematics of the normal knee joint, various attempts have been made on the design of knee implants to reconstruct normal kinematics after replacement surgery. All of these implants have satisfying survivorship, but unicondylar arthroplasty which retains both cruciate ligaments has the best clinical results with survivorship at 15 years 93%. In total knee replacement (TKR) the Anterior Cruciate Ligament (ACL) and possibly the Posterior Cruciate Ligament (PCL) are sacrified. When sacrificing the one or both of the cruciate ligaments, natural knee kinematics are affected. The function of the cruciate ligaments can be mimicked by different designs of the tibial insert.
The most used knee implant in Norway, the NexGen Cruciate-retaining (CR) implant design, does not retain the ACL and does not mimic natural knee kinematics. The tibial insert of the medial pivot implant design (GMK Sphere) has a constrained medial ball in socket joint and at the same time allows lateral anterioposterior movement. This new design was developed by a group of dedicated researchers. The design intention is to resemble the function of the cruciate ligaments and at the same time allow for lateral anterioposterior movement (rollback).
Small alterations in implant design can influence the survival of implants. The final design of the GMK Sphere was introduced in 2012. New implants should be monitored and assessed in small, controlled trials with high precision measuring methods.
Analytical Method
RSA has been used in orthopedic research fields since 1970s. The original application of this method was for the evaluation of implant migration (i.e. fixation) and polyethylene wear of artificial joints using static X-ray pictures. Clinically relevant association between early migration of tibial implants detected by RSA and late revision for loosening has been reported. Also, attempts to measure in vivo polyethylene wear have been reported using RSA.
Purpose of this study
The aim of this study is to analyse the in vivo performance (e.g. stability) of a medially stabilized knee arthroplasty implant (Medacta International, GMK Sphere) using static RSA method over a period of 5 years. 2-year results have already been analysed and are inconclusive in regards to migration as the implant is apparently stable, but shows greater than anticipated movement. Mid-term follow-up (5-year) is therefore essential to evaluate migration of this implant. We therefore wish to obtain 5-year follow-ups of these patients.
Additionally, the investigators will analyse the wear in the ball and socket (medial) side of the tibiofemoral articulation.
30 patients will go through stability and wear testing with static RSA.
This study will contribute to the safety for patients with this new implant by providing basic knowledge of this knee arthroplasty and promoting further development of knee implant designs.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- Prospective interventional single group cohort study of a cemented medial pivot knee implant, using the diagnostic method of RSA.
| Arm | Type | Receives |
|---|---|---|
| GMK Sphere | Other | Procedure: Medacta International, GMK Sphere medially stabilized kneePatients receive a GMK Sphere Total Knee Replacement. |
Who may qualify
- Ages
- 50 to 75 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (1 listed)
- Patients with knee osteoarthritis
Key exclusion criteria (11 listed)
- Preoperative severe deformity (Femoro-tibial angle < 175°or > 190°measured on a full-length leg image at weight bearing)
- Preoperative flexion contracture more than 15°
- Preoperative limited range of motion under anesthetics (less than 110°)
- Less than 50 or more than 75 years of age at the time of surgery
- Use of walking aids because of other musculoskeletal and neuromuscular problems
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 |
|---|---|---|
| Medacta International, GMK Sphere medially stabilized kneeTotal Knee Replacement | Procedure or surgery | GMK Sphere |
Primary outcome
Stability of the GMK Sphere prosthesis measured by Radiostereometric Analysis (RSA)
Time frame: 5 years
Stability of the implant is measured in mm after 5 years (Maximum Total Point Motion in mm, MTPM)
7 secondary outcomes
Knee Society Score (KSS)
Time frame: 5 years
Forgotten Joint Score 12 (FJS-12)
Time frame: 5 years
Knee injury and Osteoarthritis Outcome Score (KOOS)
Time frame: 5 years
Range of motion (ROM)
Time frame: 5 years
Hip-knee-ankle angle (HKA-angle)
Time frame: 5 years
CT-rotation of implants
Time frame: 5 years
Stability of the GMK Sphere prosthesis
Time frame: 5 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 25 Nov 2025.
- Background: PubMed 17403800Kurtz S, Ong K, Lau E, Mowat F, Halpern M. Projections of primary and revision hip and knee arthroplasty in the United States from 2005 to 2030. J Bone Joint Surg Am. 2007 Apr;89(4):780-5. doi: 10.2106/JBJS.F.00222.
- Background: PubMed 19360453Kurtz SM, Lau E, Ong K, Zhao K, Kelly M, Bozic KJ. Future young patient demand for primary and revision joint replacement: national projections from 2010 to 2030. Clin Orthop Relat Res. 2009 Oct;467(10):2606-12. doi: 10.1007/s11999-009-0834-6. Epub 2009 Apr 10.
- Background: PubMed 17964352Learmonth ID, Young C, Rorabeck C. The operation of the century: total hip replacement. Lancet. 2007 Oct 27;370(9597):1508-19. doi: 10.1016/S0140-6736(07)60457-7.
- Background: PubMed 21518317Dieppe P, Lim K, Lohmander S. Who should have knee joint replacement surgery for osteoarthritis? Int J Rheum Dis. 2011 May;14(2):175-80. doi: 10.1111/j.1756-185X.2011.01611.x.
- Background: PubMed 22398175Carr AJ, Robertsson O, Graves S, Price AJ, Arden NK, Judge A, Beard DJ. Knee replacement. Lancet. 2012 Apr 7;379(9823):1331-40. doi: 10.1016/S0140-6736(11)60752-6. Epub 2012 Mar 6.
- Background: PubMed 23459843Hawker GA, Badley EM, Borkhoff CM, Croxford R, Davis AM, Dunn S, Gignac MA, Jaglal SB, Kreder HJ, Sale JE. Which patients are most likely to benefit from total joint arthroplasty? Arthritis Rheum. 2013 May;65(5):1243-52. doi: 10.1002/art.37901.
- Background: PubMed 22178464Wylde V, Jeffery A, Dieppe P, Gooberman-Hill R. The assessment of persistent pain after joint replacement. Osteoarthritis Cartilage. 2012 Feb;20(2):102-5. doi: 10.1016/j.joca.2011.11.011. Epub 2011 Nov 30.
- Background: PubMed 23218428Ravi B, Croxford R, Reichmann WM, Losina E, Katz JN, Hawker GA. The changing demographics of total joint arthroplasty recipients in the United States and Ontario from 2001 to 2007. Best Pract Res Clin Rheumatol. 2012 Oct;26(5):637-47. doi: 10.1016/j.berh.2012.07.014.
- Background: PubMed 20223054Ibrahim T, Bloch B, Esler CN, Abrams KR, Harper WM. Temporal trends in primary total hip and knee arthroplasty surgery: results from a UK regional joint register, 1991-2004. Ann R Coll Surg Engl. 2010 Apr;92(3):231-5. doi: 10.1308/003588410X12628812458572. Epub 2010 Mar 10.
- Background: PubMed 23122654Watanabe T, Ishizuki M, Muneta T, Banks SA. Knee kinematics in anterior cruciate ligament-substituting arthroplasty with or without the posterior cruciate ligament. J Arthroplasty. 2013 Apr;28(4):548-52. doi: 10.1016/j.arth.2012.06.030. Epub 2012 Oct 31.
- Background: PubMed 23140906Bell SW, Young P, Drury C, Smith J, Anthony I, Jones B, Blyth M, McLean A. Component rotational alignment in unexplained painful primary total knee arthroplasty. Knee. 2014 Jan;21(1):272-7. doi: 10.1016/j.knee.2012.09.011. Epub 2012 Nov 7.
- Background: PubMed 14669200Smith PN, Refshauge KM, Scarvell JM. Development of the concepts of knee kinematics. Arch Phys Med Rehabil. 2003 Dec;84(12):1895-902. doi: 10.1016/s0003-9993(03)00281-8.
- Individual participant dataSharing planned: No
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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.
Stephan Maximillian Røhrl, MD, PhD study director
Center for Implant and Radiostereometric Research Oslo (CIRRO)
Frank-David Oehrn, MD principal investigator
Kristiansund Hospital, Helse More and Romsdal Trust
Lars Harald William Engseth, MD, PhD principal investigator
Center for Implant and Radiostereometric Research Oslo (CIRRO)
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Medacta International, GMK Sphere medially stabilized knee in people with Knee Osteoarthritis, run by Oslo University Hospital at 1 site in Norway.
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 1 inclusion and 11 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 25 Nov 2025. 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 Norway. 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?
Stability of the GMK Sphere prosthesis measured by Radiostereometric Analysis (RSA) (time frame: 5 years). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT02861794, which also lists 28 linked publications.
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 25 Nov 2025.