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Mobile - Bearing Knee Study

This study has been completed.
Information provided by:
Encore Medical, L.P. Identifier:
First received: September 30, 2008
Last updated: May 10, 2011
Last verified: May 2011
To evaluate the safety and efficacy of the Encore Mobile-Bearing Knee.

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

Study Type: Interventional
Study Design: Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Encore Mobile - Bearing Knee Study #200

Further study details as provided by Encore Medical, L.P.:

Primary Outcome Measures:
  • 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).

  • 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.

  • 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.

Enrollment: 419
Study Start Date: January 2000
Study Completion Date: August 2008
Primary Completion Date: June 2008 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
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


Ages Eligible for Study:   18 Years and older   (Adult, Senior)
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).
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT00765362

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.
  More Information

Additional Information:
Responsible Party: Jane M. Jacob Ph.D., DJO Surgical Identifier: NCT00765362     History of Changes
Other Study ID Numbers: Study 200
Study First Received: September 30, 2008
Results First Received: June 16, 2010
Last Updated: May 10, 2011

Additional relevant MeSH terms:
Joint Diseases
Musculoskeletal Diseases
Rheumatic Diseases
Pathologic Processes processed this record on August 22, 2017