Understanding GMK Sphere Implant Tibiofemoral Kinematics by Means of Dynamic Videofluoroscopy

Dr. Renate List

Status: Completed

Conditions: Tibiofemoral Kinematics; Total Knee Arthroplasty

Treatments: Radiation: Observational use of fluoroscopy

Study type: Observational

Funder types: Other

Identifiers

NCT03041857

MedactaGMKSphere

Details and patient eligibility

About

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.

Full 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.

Enrollment: 30 patients

Sex: All

Ages: 40 to 100 years old

Volunteers: No Healthy Volunteers

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)

Trial design

30 participants in 3 patient groups

GMK Sphere

Description:

Subjects with a unilateral Medacta GMK Sphere TKA

Treatment:

Radiation: Observational use of fluoroscopy

GMK PS

Description:

Subjects with a unilateral Medacta GMK Primary PS Fixed Bearing TKA

Treatment:

Radiation: Observational use of fluoroscopy

GMK UC

Description:

Subjects with a unilateral Medacta GMK Primary UC Fixed Bearing TKA

Treatment:

Radiation: Observational use of fluoroscopy