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Mobile - Bearing Knee Study

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00765362
Recruitment Status : Completed
First Posted : October 2, 2008
Results First Posted : April 19, 2011
Last Update Posted : May 11, 2011
Information provided by:
Encore Medical, L.P.

Brief Summary:
To evaluate the safety and efficacy of the Encore Mobile-Bearing Knee.

Condition or disease Intervention/treatment Phase
Inflammatory Tissue Disorder Osteoarthritis Avascular Necrosis Post-traumatic Arthritis Secondary Arthritis Device: Encore Mobile-Bearing Knee Phase 3

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 419 participants
Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Encore Mobile - Bearing Knee Study #200
Study Start Date : January 2000
Actual Primary Completion Date : June 2008
Actual Study Completion Date : August 2008

Arm Intervention/treatment
Experimental: 1
Subjects who are candidates for a total knee replacement and meet the inclusion/exclusion criteria of the study.
Device: Encore Mobile-Bearing Knee
Used for primary total knee replacement
Other Name: MBK

Primary Outcome Measures :
  1. Knee Society Score Evaluation [ Time Frame: 2 year ]
    The Knee Society Score includes a knee rating and function score. This evaluation covers the knee rating score with three main parameters of pain, stability and range of motion and that flexion contracture, extension lag and misalignment should be dealt with as deductions. Thus, 100 points will be obtained by a well-aligned knee with no pain, 125 degrees of motion, and negligible anteroposterior and mediolateral instability. 50 points are allotted for pain, 25 for stability, and 25 for range of motion. Grading for KS Score: Excellent (90-100), Good (80-90), Fair (70-79) and Poor (<70).

  2. Knee Society Function Score [ Time Frame: 2 year ]
    The patient function score considers only walking distance and stair climbing, with deductions for walking aids. The maximum function score is obtained by a patient who can walk an unlimited distance and go up and down stairs normally. Walking ability is expressed in blocks (approximately 100 meters). Stair climbing is considered normal if the patient can ascend and descend stairs without holding a railing. A score of > or = to 60 on the function score is considered success. Minimum score = 0, maximum score = 100 with the higher the score representing a better outcome.

  3. Knee Society Scores Used as Success/Failure Criteria. [ Time Frame: 2 year ]
    The maximum score for each of the sections is 100 points. A score of at least 80 points on the 2-year knee assessment score was defined as a success.

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Skeletal maturity
  • Less than 70 on preoperative Knee Society Score (Rating Score)
  • Sufficient bone stock, as judged by radiographs, to support primary knee implant
  • Patients with inflammatory tissue disorders, osteoarthritis, post-traumatic arthritis, secondary arthritis, or avascular necrosis of the femoral condyles
  • Patient is not pregnant
  • Primary total knee replacement
  • Sufficient collateral ligaments to support device, as judged by physician during stability testing (varus/valgus and flexion/extension)
  • Varus deformity <45 or valgus deformity <45 or fixed flexion deformity <90
  • Patient is likely to be available for evaluation for the duration of the study
  • Able and willing to sign the informed consent and follow study procedures

Exclusion Criteria:

  • Skeletal immaturity
  • Greater than or equal to 70 on preoperative Knee Society Score (Rating Scale)
  • Previous knee surgery that has adversely affected bone stock or prior total knee replacement
  • Post patellectomy
  • Patient is pregnant
  • Insufficient collateral ligaments, as judged by the physician
  • Neurological conditions that might hinder patient's ability to follow study procedures (i.e., any that restrict physical activities such as Parkinson's Disease, Multiple Sclerosis, previous stroke which affects lower extremity).
  • Varus deformity >45 or valgus deformity >45 or fixed flexion deformity >90.
  • Mental conditions that may interfere with ability to give an informed consent or willingness to fulfill the study requirements (i.e., severe mental retardation such that the patient cannot understand the informed consent process, global dementia, prior strokes that interfere the with patient's cognitive abilities, senile dementia, and Alzheimer's Disease).
  • Prisoners
  • Conditions that place excessive demand on the implant (i.e. Charcot's joints, muscle deficiencies, refusal to modify postoperative physical activities, skeletal immaturity).

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 identifier (NCT number): NCT00765362

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United States, Arizona
Carl T. Hayden VA Hospital
Phoenix, Arizona, United States, 85012
United States, California
Orange Coast Memorial Medical Center
Fountain Valley, California, United States, 92708
United States, Florida
S.Florida VA Found. For Research & Education, Inc.
Miami, Florida, United States, 33125
United States, Michigan
Great Lakes Orthopaedics
Garden City, Michigan, United States, 48135
United States, South Carolina
Hilton Head Island, South Carolina, United States, 29926
United States, Texas
Orthopedic Surgery Center and Sports Medicine
Edinburg, Texas, United States, 78539
United States, Utah
The Orthopedic Specialty Hospital
Murray, Utah, United States, 84107
West Jordan, Utah, United States, 84084
Sponsors and Collaborators
Encore Medical, L.P.
Additional Information:
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Responsible Party: Jane M. Jacob Ph.D., DJO Surgical Identifier: NCT00765362    
Other Study ID Numbers: Study 200
First Posted: October 2, 2008    Key Record Dates
Results First Posted: April 19, 2011
Last Update Posted: May 11, 2011
Last Verified: May 2011
Additional relevant MeSH terms:
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Joint Diseases
Musculoskeletal Diseases
Pathologic Processes