Understanding GMK Sphere Implant Tibiofemoral Kinematics by Means of Dynamic Videofluoroscopy

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.

Study Overview

• Status: Completed
• Conditions: Total Knee Arthroplasty; Tibiofemoral Kinematics
• Intervention / Treatment: Radiation: Observational use of fluoroscopy

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.

• Study Type: Observational
• Enrollment (Actual): 30

Contacts and Locations

Study Locations

• Switzerland
  • Zurich, Switzerland, 8093
    • Institute for Biomechanics, ETH Zürich

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 38 years to 98 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• 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.

Description

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:

• 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)

Study Plan

How is the study designed?

Design Details

• Observational Models: Case-Control
• Time Perspectives: Cross-Sectional

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
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

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	3 hours

Collaborators and Investigators

• Sponsor: Dr. Renate List
• Collaborators: Balgrist University Hospital; Kantonsspital Winterthur KSW
• Investigators: Principal Investigator: Renate List, Dr., Institute for Biomechanics, ETH Zürich

Study record dates

Study Major Dates

• Study Start (Actual): December 1, 2013
• Primary Completion (Actual): August 1, 2017
• Study Completion (Actual): September 1, 2017

Study Registration Dates

• First Submitted: March 4, 2016
• First Submitted That Met QC Criteria: February 1, 2017
• First Posted (Estimate): February 3, 2017

Study Record Updates

• Last Update Posted (Actual): September 29, 2017
• Last Update Submitted That Met QC Criteria: September 28, 2017
• Last Verified: September 1, 2017

More Information

Terms related to this study

• Keywords: GMK Sphere; Videofluoroscopy; GMK PS Fixed Bearing; GMK UC Mobile Bearing
• Other Study ID Numbers: MedactaGMKSphere

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No