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OpenTrials
Completed

NCT Number: NCT01882751

In Vivo Comparison of Knee Kinematics for Subjects Implanted With Either a ConforMIS or Traditional Knee Implant

A better understanding of knee joint kinematics is important to explain the premature polyethylene wear failures within total knee arthroplasties (TKAs) and to help design a prosthesis that most closely approximates the normal knee. Previously, most experimental studies of knee kinematics have involved cadaveric, in vitro analyses, or have not tested the knee in a weight-bearing mode. Others have used exoskeletal linkages and skin markers that permit error due to undesired motions between markers and the underlying bone. More recently, fluoroscopy has been used to assess in vivo kinematics for subjects having a TKA.

ConforMIS has attempted to follow a clearly different path than the major orthopaedic companies. They have chosen to offer patients a personalized knee implant based off of each patient's femoral and tibial bone geometry. The hypothesis is that these subjects will experience a more normal-like kinematic pattern, eliminating paradoxical anterior sliding during weight-bearing knee flexion. Therefore, the objective for this study is to analyze the in vivo kinematics for 25 patients implanted with a personalized ConforMIS TKA and 25 patients implanted with a traditional TKA design to determine if there are any kinematic differences between these TKA designs.

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Key information

Conditions

Complications; Arthroplasty

Age range

40 year–70 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Tennessee Orthopaedic Clinics, Knoxville, Tennessee, United States

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About this study

Each subject will be asked to perform five activities in one continuous sequence: (1) stand up from a chair, (2) walk up stairs, (3) walk down stairs, (4) level walking, and (5) a deep knee bend. Subjects will be video recorded from the waist down while performing the activities. The speed level of each trial will be based on the comfort level of the patient. The fluoroscopic images will be stored digitally for subsequent analysis on secure servers and workstations at the University of Tennessee.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • At least 6 months post-op
  • Between 40-70 years of age
  • Body weight of less than 250lbs
  • TKA patients will be judged clinically successful with an American Knee Society score of greater than 90
  • Must have post-op passive flexion of 100 degrees with no ligamentous laxity or pain
  • Participants must be able to walk on level ground without aids and ascend/descend stairs without assistance.
  • Subjects will either a ConforMIS™ TKA or a traditional TKA manufactured by any other orthopaedic company.
  • Patients must be between 160cm (5'3) and 193cm (6'4) tall.

Exclusion criteria

  • Subjects not willing to sign the Informed Consent and HIPAA forms to participate in the study
  • BMI >40
  • Pregnant females
  • Surgical procedures conducted within the past 6 months other than TKA
  • Subjects from the physician's list who do not meet study requirements
  • Unwilling or unable to comply with study requirements
  • Participation in another clinical study which would confound results

Treatment and study plan

Conformis CR Total Knee Replacement

Device

iTotal CR by Conformis

Off the Shelf

Device

A standard knee replacement not using ConforMIS' iFit technology

Primary outcomes

  1. Kinematic Patterns during gait

    Time frame: at least 6 months post surgery

    There are multiple parameters captured by fluoroscopy that will be assessed during these 4 activities including:

    • Anterior/posterior medial and lateral condyle contact positions
    • Axial rotation of the femoral component relative to the tibial component
    • Condylar lift-off will be determined by measuring the distances from the medial and lateral condyles to the polyethylene insert surface
    • Weight-bearing range-of-motion.

  2. Kinematic patterns during deep knee bend

    Time frame: at least 6 months post surgery

    There are multiple parameters captured by fluoroscopy that will be assessed during these 4 activities including:

    • Anterior/posterior medial and lateral condyle contact positions
    • Axial rotation of the femoral component relative to the tibial component
    • Condylar lift-off will be determined by measuring the distances from the medial and lateral condyles to the polyethylene insert surface
    • Weight-bearing range-of-motion.

  3. Kinematics patterns during going up and down stairs

    Time frame: at least 6 months post surgery

    There are multiple parameters captured by fluoroscopy that will be assessed during these 4 activities including:

    • Anterior/posterior medial and lateral condyle contact positions
    • Axial rotation of the femoral component relative to the tibial component
    • Condylar lift-off will be determined by measuring the distances from the medial and lateral condyles to the polyethylene insert surface
    • Weight-bearing range-of-motion.

  4. Kinematics patterns during getting up from chair

    Time frame: at least 6 months post surgery

    There are multiple parameters captured by fluoroscopy that will be assessed during these 4 activities including:

    • Anterior/posterior medial and lateral condyle contact positions
    • Axial rotation of the femoral component relative to the tibial component
    • Condylar lift-off will be determined by measuring the distances from the medial and lateral condyles to the polyethylene insert surface
    • Weight-bearing range-of-motion.

Sponsors and collaborators

Lead sponsor

Restor3D

Industry

Registry information

Official study title

In Vivo Determination & Comparison of Knee Kinematics for Subjects Implanted With Either a Personalized ConforMIS or Traditional Knee Implant

Important dates

Study start
2013
Primary completion
2017
Study completion
2017
First posted
Jun 20, 2013
Registry last updated
Oct 25, 2023

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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