Medacta GMK Sphere® vs. Medacta GMK PS Post-Market Outcomes Study

Study Overview
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Brief Summary
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The study is a prospective, randomized comparison of total knee arthroplasty with the Medacta GMK Sphere® knee compared to the Medacta GMK PS knee, with comparison to data from previous trials of similar study design.

Official Title
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Medacta GMK Sphere® Medial-Pivot, Cruciate Substituting vs. Medacta GMK PS Posterior Stabilized Kne vs. OMNI Apex Knee Ultracongruent vs. Triathlon® Posterior Stabilized & Cruciate Substituting Outcomes Study

Conditions
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Osteoarthritis, Osteoarthritis, Knee, Joint Disease

Intervention / Treatment
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* Device: Medacta GMK Sphere® Medial-Pivot Knee Prosthesis
* Device: Medacta GMK PS Posterior Stabilized Knee Prosthesis


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients willing to sign the Informed Consent. Patients able to comply with follow-up requirements including postoperative weight bearing restrictions and self-evaluations. Male and non-pregnant female patients ages 21 - 80 years of age at the time of surgery. Patients requiring a primary total knee replacement. Patients with a diagnosis of osteoarthritis (OA), traumatic arthritis (TA), or avascular necrosis (AVN). Patients with intact collateral ligaments. Exclusion Criteria: Patients with inflammatory arthritis. Patients that are morbidly obese, body mass index (BMI) > 40. Patients with a history of total or unicompartmental reconstruction of the affected joint. Patients with neuromuscular or neurosensory deficiency, which would limit the ability to assess the performance of the device. Patients with a systemic or metabolic disorder leading to progressive bone deterioration. Patients that are immunologically compromised, or receiving chronic steroids (>30 days), excluding inhalers. Patients bone stock is compromised by disease or infection, which cannot provide adequate support and/or fixation to the prosthesis. Patients with knee fusion to the affected joint. Patients with an active or suspected latent infection in or about the knee joint. Patients whose surgery will utilize computer-assisted surgical navigation (CAOS) techniques. Patients whose surgery will utilize minimally invasive surgical techniques. Patients that are prisoners.

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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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

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


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Medacta GMK Sphere® Medial-Pivot Knee Prosthesis<br> | Device: Medacta GMK Sphere® Medial-Pivot Knee Prosthesis<br> <br> |
| Other: Medacta GMK PS Posterior Stabilized Knee Prosthesis<br> | Device: Medacta GMK PS Posterior Stabilized Knee Prosthesis<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Forgotten Joint Score (FJS) | The average Forgotten Joint Score (FJS) of those patients receiving the Medacta GMK Sphere® knee prosthesis will be compared with the average FJS of those receiving the Medacta GMK PS knee prosthesis. The FJS total score range is 0-100, with higher scores indicating a higher degree of forgetting the artificial joint, that is, a lower degree of awareness. | Change from baseline at 2 years and 5 years post-operative | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Total Knee Society Score (KSS) | Clinical outcomes will be evaluated via the Knee Society Score (KSS). The KSS is subdivided into a Knee Assessment score which rates only the knee joint itself, and a Functional Assessment score which rates the subject's ability to walk and climb stairs. Both scores range from 0-100, with a higher score indicating a better outcome. | Pre-operative, 6 weeks, 6 months, 1, 2, 3, 4, and 5 years post-operative | 
| Lower Extremity Activity Scale (LEAS) | Clinical outcomes will be evaluated via the Lower Extremity Activity Scale (LEAS). The LEAS scale range is 1-18, with a higher value indicating a higher level of activity. | Pre-operative, 6 weeks, 6 months, 1, 2, 3, 4, and 5 years post-operative | 
| Radiographic Analysis | Radiographs will be assessed for radiolucency, migration and subsidence. An AP Longstanding view will be obtained pre-operatively, and at 6 weeks and 1 year post-operatively to determine degree of Varus or Valgus. | Pre-operative, 6 weeks, 6 months, 1, 2, 3, 4, and 5 years post-operative |