Mobile - Bearing Knee Study

• Sponsor: Encore Medical, L.P. (Industry)
• Overall Status: Completed
• CT.gov ID: NCT00765362
• Collaborator: (none)
• Enrollment: 419
• Locations: 8
• Arm: 1
• Duration (Months): 103
• Patients Per Site: 52.4
• Patients Per Site Per Month: 0.5

Study Details

Study Description

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

Study Design

• Study Type: Interventional
• 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: Jan 1, 2000
• Actual Primary Completion Date: Jun 1, 2008
• Actual Study Completion Date: Aug 1, 2008

Arms and Interventions

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 Names: MBK

Outcome Measures

Primary Outcome Measures

1. Knee Society Score Evaluation [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 [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. [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.

Eligibility Criteria

Criteria

• Ages Eligible for Study: 18 Years and Older
• 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

Locations

	Site	City	State	Country	Postal Code
1	Carl T. Hayden VA Hospital	Phoenix	Arizona	United States	85012
2	Orange Coast Memorial Medical Center	Fountain Valley	California	United States	92708
3	S.Florida VA Found. For Research & Education, Inc.	Miami	Florida	United States	33125
4	Great Lakes Orthopaedics	Garden City	Michigan	United States	48135
5		Hilton Head Island	South Carolina	United States	29926
6	Orthopedic Surgery Center and Sports Medicine	Edinburg	Texas	United States	78539
7	The Orthopedic Specialty Hospital	Murray	Utah	United States	84107
8		West Jordan	Utah	United States	84084

Sponsors and Collaborators

• Encore Medical, L.P.

Investigators

None specified.

Study Documents (Full-Text)

None provided.

More Information

Additional Information:

• Sponsor company home page

Publications

None provided.

• ClinicalTrials.gov Identifier: NCT00765362
• Other Study ID Numbers: Study 200
• First Posted: Oct 2, 2008
• Last Update Posted: May 11, 2011
• Last Verified: May 1, 2011

• Additional relevant MeSH terms: Arthritis; Necrosis

Study Results

Participant Flow

Arm/Group Title	Mobile Bearing Knee
Arm/Group Description	Subjects who meet the inclusion/exclusion criteria and are treated and receive the Mobile Bearing Knee. The Encore Mobile Bearing Knee is intended for subjects presenting for a primary cemented knee replacement suffering from inflammatory tissue disorders, osteoarthritis, post-traumatic arthritis, secondary arthritis, or avascular necrosis of the femoral condyles. This design is indicated for subjects who have adequate, as judged by the physician, collateral ligamentous stability to support the implant.
Period Title: Overall Study
STARTED	419
COMPLETED	282
NOT COMPLETED	137

Baseline Characteristics

Arm/Group Title	Mobile Bearing Knee
Arm/Group Description	Subjects who meet the inclusion/exclusion criteria and are treated and receive the Mobile Bearing Knee. The Encore Mobile Bearing Knee is intended for subjects presenting for a primary cemented knee replacement suffering from inflammatory tissue disorders, osteoarthritis, post-traumatic arthritis, secondary arthritis, or avascular necrosis of the femoral condyles. This design is indicated for subjects who have adequate, as judged by the physician, collateral ligamentous stability to support the implant.
Overall Participants	419
Age (Count of Participants)
<=18 years	0 0%
Between 18 and 65 years	181 43.2%
>=65 years	238 56.8%
Age (years) [Mean (Standard Deviation) ]
Mean (Standard Deviation) [years]	66.8 (10.2)
Sex: Female, Male (Count of Participants)
Female	229 54.7%
Male	190 45.3%
Region of Enrollment (participants) [Number]
United States	419 100%

Outcome Measures

1. Primary Outcome

Title	Knee Society Score Evaluation
Description	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).
Time Frame	2 year

Outcome Measure Data

Analysis Population Description

Out of the 282 subjects who completed the study, only 173 were analyzed due to either the 2 year visit being completed out of window or missing data.

Arm/Group Title	Mobile Bearing Knee
Arm/Group Description	Subjects who meet the inclusion/exclusion criteria and are treated and receive the Mobile Bearing Knee. The Encore Mobile Bearing Knee is intended for subjects presenting for a primary cemented knee replacement suffering from inflammatory tissue disorders, osteoarthritis, post-traumatic arthritis, secondary arthritis, or avascular necrosis of the femoral condyles. This design is indicated for subjects who have adequate, as judged by the physician, collateral ligamentous stability to support the implant.
Measure Participants	173
Mean (Standard Deviation) [Average Knee Rating Score]	93.1 (9.9)

2. Primary Outcome

Title	Knee Society Function Score
Description	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.
Time Frame	2 year

Outcome Measure Data

Analysis Population Description

Out of the 282 subjects who completed the study, only 173 were analyzed due to either the 2 year visit being completed out of window or missing data.

Arm/Group Title	Mobile Bearing Knee
Arm/Group Description	Subjects who meet the inclusion/exclusion criteria and are treated and receive the Mobile Bearing Knee. The Encore Mobile Bearing Knee is intended for subjects presenting for a primary cemented knee replacement suffering from inflammatory tissue disorders, osteoarthritis, post-traumatic arthritis, secondary arthritis, or avascular necrosis of the femoral condyles. This design is indicated for subjects who have adequate, as judged by the physician, collateral ligamentous stability to support the implant.
Measure Participants	173
Mean (Standard Deviation) [Average Knee Function Score]	89.0 (15.6)

3. Primary Outcome

Title	Knee Society Scores Used as Success/Failure Criteria.
Description	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.
Time Frame	2 year

Outcome Measure Data

Analysis Population Description

Out of the 282 subjects who completed the study, only 173 were analyzed due to either the 2 year visit being completed out of window or missing data.

Arm/Group Title	Mobile Bearing Knee
Arm/Group Description	Subjects who meet the inclusion/exclusion criteria and are treated and receive the Mobile Bearing Knee. The Encore Mobile Bearing Knee is intended for subjects presenting for a primary cemented knee replacement suffering from inflammatory tissue disorders, osteoarthritis, post-traumatic arthritis, secondary arthritis, or avascular necrosis of the femoral condyles. This design is indicated for subjects who have adequate, as judged by the physician, collateral ligamentous stability to support the implant.
Measure Participants	173
Knee Society Score Success	91 21.7%
Knee Function Score Success	84 20%

Adverse Events

Time Frame	Adverse events were collected from the date of surgery through the 2 year visit.
Arm/Group Title	Mobile Bearing Knee
Arm/Group Description	Subjects who meet the inclusion/exclusion criteria and are treated and receive the Mobile Bearing Knee. The Encore Mobile Bearing Knee is intended for subjects presenting for a primary cemented knee replacement suffering from inflammatory tissue disorders, osteoarthritis, post-traumatic arthritis, secondary arthritis, or avascular necrosis of the femoral condyles. This design is indicated for subjects who have adequate, as judged by the physician, collateral ligamentous stability to support the implant.
All Cause Mortality
	Mobile Bearing Knee
	Affected / at Risk (%)	# Events
Total	/ (NaN)
Serious Adverse Events
	Mobile Bearing Knee
	Affected / at Risk (%)	# Events
Total	0/419 (0%)
Other (Not Including Serious) Adverse Events
	Mobile Bearing Knee
	Affected / at Risk (%)	# Events
Total	281/419 (67.1%)
Blood and lymphatic system disorders
Edema	13/419 (3.1%)	13
Cardiac disorders
Heart Complications	10/419 (2.4%)	10
Immune system disorders
Cancer	10/419 (2.4%)	10
Infections and infestations
Infections	16/419 (3.8%)	16
Injury, poisoning and procedural complications
Knee device clicking	9/419 (2.1%)	9
Musculoskeletal and connective tissue disorders
Arthrofibrosis	12/419 (2.9%)	13
Degenerative Arthritis	8/419 (1.9%)	9
Fracture	8/419 (1.9%)	8
Musculoskeletal pain	203/419 (48.4%)	328
Nervous system disorders
Neurological disorder and numbness	11/419 (2.6%)	11
Vascular disorders
Swelling	19/419 (4.5%)	20

Limitations/Caveats

[Not Specified]

More Information

Certain Agreements

Principal Investigators are NOT employed by the organization sponsoring the study.

The only disclosure restriction on the PI is that the sponsor can review results communications prior to public release and can embargo communications regarding trial results for a period that is less than or equal to 60 days. The sponsor cannot require changes to the communication and cannot extend the embargo.