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CompletedNCT03041857Updated Sep 29, 2017

Understanding GMK Sphere Implant Tibiofemoral Kinematics by Means of Dynamic Videofluoroscopy

An observational study in Total Knee Arthroplasty and Tibiofemoral Kinematics, sponsored by Dr. Renate List. Completed at 1 site in Switzerland. Open to participants aged 40 Years to 100 Years. Per ClinicalTrials.gov, last updated 2017-09-29.

Sponsored by Dr. Renate List · Observational

Study type
Observational
Model
Case-control
Time perspective
Cross-sectional
Enrollment
30
Ages
40 Years to 100 Years
Sex
All
01

Study summary

The objective of this research project is to perform a comparative study on the in vivo kinematics of the GMK Sphere prosthesis in comparison to the conventional GMK PS Fixed Bearing TKA as well as to the GMK UC Mobile Bearing during level walking, stair descent and downhill walking by means of videofluoroscopy.

Read the detailed description

Total arthroplasty of the knee (TKA) aims to relieve patient pain and improve functionality of the joint. To maintain sufficient range of motion, but also not overload the surrounding soft tissue structures, reproduction of tibio-femoral kinematics of the healthy knee is thought to be beneficial. In previous studies, it has been shown that the medial condyle, described by the centre of the medial condylar sphere, does not move anterioposteriorly during progressing joint flexion, whereas the lateral condyle has been observed to translate in a posterior direction producing tibial internal rotation with flexion (Freeman and Pinskerova 2003, Pinskerova, Johal et al. 2004, Freeman and Pinskerova 2005). The GMK Sphere prosthesis is specifically designed to mimic the healthy kinematics with providing a medial pivot.

The objective of this research project is to perform a comparative study on the in vivo kinematics of the GMK Sphere prosthesis in comparison to the conventional GMK PS Fixed Bearing TKA as well as to the GMK UC Fixed Bearing. The study includes the simultaneous assessment of the 3D kinematics of the TKA by means of an automated moving fluoroscope and subsequent 2D/3D registration based on CAD models of the TKA, whole leg kinematics by means of skin markers and ground reaction forces during level walking, stair descent and downhill walking a 10° inclined slope. Precisely, the aim is to assess tibio-femoral kinematics in 8-10 TKA subjects implanted one or more years previously with the GMK Sphere prosthesis. In addition, 8-10 conventional GMK PS Fixed Bearing TKA subjects, as well as 8-10 GMK UC Mobile Bearing TKA subjects will be measured to provide a comparison against the GMK Sphere prosthesis kinematics.

02

Conditions studied

  • Total Knee Arthroplasty
  • Tibiofemoral Kinematics

Keywords

  • Videofluoroscopy
  • GMK Sphere
  • GMK PS Fixed Bearing
  • GMK UC Mobile Bearing
03

In context

Lead sponsor

Dr. Renate List is the lead sponsor of 3 studies on the registry; none are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
40 Years to 100 Years
Sexes eligible
All
Accepts healthy volunteers
No
Sampling method
Probability sample

Study population

Participants fulfilling all of the following inclusion criteria are eligible for the study. The presence of any one of the following exclusion criteria will lead to the exclusion of the participant.

Inclusion criteria

  • Female or male
  • Age: 40 to 100 years
  • Unilateral TKA
  • ≥ 1 years postoperatively
  • BMI ≤ 33
  • Good outcome, WOMAC between 0 to 28 (0-14 (Excellent), 15-28 (Good)) No pain subjects, VAS ≤ 2
  • Good health condition, adequate for test procedure

Exclusion criteria

Exclusion Criteria:

  • Other actual significant problem on lower extremities
  • Any other arthroplasty at the lower extremities
  • Subject incapable to understand and sign informed consent
  • Pregnancy at time of testing
  • Incapable of performing the motion tasks
  • Misaligned TKA (≥ ± 3° from mechanical axis)
05

Study design

Observational model
Case-control
Time perspective
Cross-sectional
Enrollment
30 participants (actual)
Patient registry
No

Groups and cohorts

  • GMK Sphere

    Subjects with a unilateral Medacta GMK Sphere TKA

    Radiation: Observational use of fluoroscopy

  • GMK PS

    Subjects with a unilateral Medacta GMK Primary PS Fixed Bearing TKA

    Radiation: Observational use of fluoroscopy

  • GMK UC

    Subjects with a unilateral Medacta GMK Primary UC Fixed Bearing TKA

    Radiation: Observational use of fluoroscopy

Interventions

  • RadiationObservational use of fluoroscopy
06

What researchers measure

Primary outcomes

  1. Comparison of the three-dimensional kinematics of the GMK Sphere Fixed Bearing TKA to the kinematics of the GMK Primary PS fixed bearing and GMK Primary UC Mobile Bearing TKA.

    With video-fluoroscopic assessment it is possible to directly measure the kinematics of the tibial and the femoral components in vivo during daily activities, such as level walking, downhill walking and stair descent. Thus, for the first time the present study provides in vivo assessed data of the 3D motion of the GMK Sphere System during daily activities. The knowledge of the in vivo kinematic behaviour of the GMK Sphere System compared to conventional GMK PS Fixed Bearing and GMK UC Mobile Bearing TKA leads to an improved understanding of the design principle. Observation of the kinematics in terms of range of motion, patterns of anterior-posterior motion of medial and lateral condyle points ("posterior femoral rollback") and tibio-femoral internal/external rotation.

    Time frame: 3 hours

07

Study locations

1 site
  • Institute for Biomechanics, ETH Zurich
    Zurich, 8093, Switzerland
08

References and documents

Individual participant data

Plan to share: No

No publications or documents are linked to this record.

09

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Sep 29, 2017, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT03041857
Lead sponsor
Dr. Renate List
Collaborators
Kantonsspital Winterthur KSW, Balgrist University Hospital
Responsible party
Dr. Renate List (Doctor of Sciences (Dr. sc. ETH), Institute for Biomechanics, ETH Zürich) — Sponsor-investigator
First posted
Feb 3, 2017
Start date
Dec 2013
Primary completion
Aug 2017
Completion
Sep 2017
Last update
Sep 29, 2017

Study contacts

Renate List, Dr.
principal investigator · Institute for Biomechanics, ETH Zurich

Oversight

Data monitoring committee
No
View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is completed, as verified in Sep 2017. You cannot join it, but the record below documents what was studied.

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