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

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ClinicalTrials.gov Identifier: NCT01882751
Recruitment Status : Completed
First Posted : June 20, 2013
Last Update Posted : September 20, 2017
Sponsor:
Information provided by (Responsible Party):
ConforMIS, Inc.

Brief Summary:

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.


Condition or disease Intervention/treatment
Complications; Arthroplasty Device: Conformis CR Total Knee Replacement Device: Off the Shelf

Detailed Description:
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.

Study Type : Observational
Actual Enrollment : 66 participants
Observational Model: Case-Control
Time Perspective: Prospective
Official Title: In Vivo Determination & Comparison of Knee Kinematics for Subjects Implanted With Either a Personalized ConforMIS or Traditional Knee Implant
Study Start Date : June 2013
Actual Primary Completion Date : July 2017
Actual Study Completion Date : August 2017

Group/Cohort Intervention/treatment
ConforMIS
Patients with ConforMIS implants
Device: Conformis CR Total Knee Replacement
iTotal CR by Conformis

Standard Total Knee Implant
Patients implanted with standard total knee implant
Device: Off the Shelf
A standard knee replacement not using ConforMIS' iFit technology




Primary Outcome Measures :
  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:

    1. Anterior/posterior medial and lateral condyle contact positions
    2. Axial rotation of the femoral component relative to the tibial component
    3. Condylar lift-off will be determined by measuring the distances from the medial and lateral condyles to the polyethylene insert surface
    4. 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:

    1. Anterior/posterior medial and lateral condyle contact positions
    2. Axial rotation of the femoral component relative to the tibial component
    3. Condylar lift-off will be determined by measuring the distances from the medial and lateral condyles to the polyethylene insert surface
    4. 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:

    1. Anterior/posterior medial and lateral condyle contact positions
    2. Axial rotation of the femoral component relative to the tibial component
    3. Condylar lift-off will be determined by measuring the distances from the medial and lateral condyles to the polyethylene insert surface
    4. 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:

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



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Ages Eligible for Study:   40 Years to 70 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
Patients who are at least 6 month post-op with a ConforMIS knee replacement or a standard total knee replacement who meets the inclusion/exclusion criteria
Criteria

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

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01882751


Locations
United States, Tennessee
Tennessee Orthopaedic Clinics
Knoxville, Tennessee, United States, 37923
University of Tennessee
Knoxville, Tennessee, United States, 37996
Sponsors and Collaborators
ConforMIS, Inc.
Investigators
Principal Investigator: Richard D Komistek, PhD Univeristy of Tennessee
Principal Investigator: Harold Cates, MD Tennessee Orthopaedic Clinics

Responsible Party: ConforMIS, Inc.
ClinicalTrials.gov Identifier: NCT01882751     History of Changes
Other Study ID Numbers: Komistek 2
First Posted: June 20, 2013    Key Record Dates
Last Update Posted: September 20, 2017
Last Verified: September 2017
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: Yes
Device Product Not Approved or Cleared by U.S. FDA: No
Pediatric Postmarket Surveillance of a Device Product: No
Product Manufactured in and Exported from the U.S.: Yes

Keywords provided by ConforMIS, Inc.:
kinematics
knee joint