A Study to Compare the NexGen CR and CR-Flex Knee Implants

Study Overview
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Brief Summary
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The purpose of this study is to test for significant differences in functional outcomes, specifically pre-operative ROM and post-operative ROM obtained by using a NexGen CR versus a NexGen CR-Flex knee implant. Specifically, it is predicted that an increase in post-operative range of motion will be experienced by patients treated with the NexGen CR-Flex knee implant.

Detailed Description
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This study will compare the clinical results of the NexGen CR femoral component with the higher flexion potential of the NexGen CR-Flex femoral component in all patients with degenerative joint disease that require total knee arthroplasty. The primary variable of interest is post-operative range of motion achieved with the two devices, which are implanted with slightly different surgical techniques in patients who may also be subjected to different rehabilitation programs depending on the device they are assigned.

Official Title
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Prospective Randomized Multicenter Study of NexGen CR-Flex Knee

Conditions
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Total Knee Arthroplasty, Osteoarthritis

Intervention / Treatment
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* Device: NexGen CR-Flex Fixed Bearing Knee
* Device: NexGen CR Knee


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age, 21-80 years Sex, Male and Females will be included BMI less than or equal to 39 Stable Health, the patient would be able to undergo surgery and participate in a follow-up program based on physical examination and medical history. Patient is willing and able to cooperate in follow-up therapy. Patient exhibits pre-operative radiographic evidenced of joint degeneration consistent with TKA that cannot be treated in non-operative fashion. Patient has stable and functional posterior cruciate and collateral ligaments. Patient has potential to perform higher than average range of motion activities. Operative side range of motion flexion greater than or equal to 120 degrees. Severe knee pain and disability due to degenerative joint disease. Patient or patient's legal representative has signed the Informed Consent form. Exclusion Criteria: Previous history of infection in the affected joint. Previously failed knee endoprosthesis of any kind. Charcot joint disease or other severe neurosensory deficits. Previous patellectomy Patient is skeletally immature. Grossly insufficient femoral or tibial bone stock. Patient is pregnant. Varus or valgus deformity greater than 20 degrees. Fixed flexion deformity greater than 15 degrees. Previous high tibial osteotomy. Previous femoral osteotomy. Patient is a poor compliance risk, currently treated for ethanol or drug abuse, physical or mental handicap, etc. Loss of musculature or absence of musculoligamentous supporting structures required for adequate soft tissue balance.

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: 1<br>Study arm will consist of patients that are treated with the NexGen CR-Flex Fixed Bearing Knee. | Device: NexGen CR-Flex Fixed Bearing Knee<br>* NexGen CR-Flex Fixed Bearing femoral component<br>* Other names: CR-Flex Knee;|
| Active Comparator: 2<br>Study arm will consist of patients that are treated with the NexGen CR Knee. | Device: NexGen CR Knee<br>* NexGen Complete Knee Solution Cruciate Retaining femoral component<br>* Other names: CR Knee;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Postoperative Range of Motion (ROM) | The subject will have the operative joint's range of motion/movement assessed through a series of exercises and bends. The assessor will measure how far the joint bends/moves in each direction by degrees. The measurements are taken at each visit interval and recorded. | 24 Months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Return to Function (RtF) Via Knee Scoiety Score (Modified) | Scores were calculated from responses on a modified Knee Society Score by the enrolled subjects for the stated visit intervals. Grading for the Knee Society Score is based on a scale from 0-100 and results are estabalished follows: 80-100 = Excellent; 70-79 = Good; 60-69 = Fair; and Below 60 = Poor. | 24 Months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Total Knee Arthroplasty, Osteoarthritis, Knee