X-3 Polyethylene Survival Outcomes Study

A Prospective, Randomized Study Comparing the Survival for X-3 Polyethylene to N2Vac Polyethylene When Used With the Triathlon Posterior Stabilized (PS) Total Knee System.

The goal of this clinical trial is to compare two types of polyethylene (Stryker Orthopaedics N2Vac and their X3 polyethylene) prostheses that are used in total knee replacements. The primary outcome will analyze whether or not prostheses require a revision surgery 10 years post knee replacement. Other outcomes such as reoperation rate, complications, radiographic results, and clinical outcomes will be collected.

It is hypothesized that X3 would perform equally well to N2Vac at 10 years.

Study Overview

• Status: Completed
• Conditions: Arthroplasty, Replacement, Knee; Total Knee Replacement
• Intervention / Treatment: Device: N2Vac Polyethylene; Device: X3 Polyethylene

Detailed Description

This is a prospective, randomized and blinded clinical trial. Participants will be assessed pre-operatively and post-operatively at three months and two, five, seven and ten years. The primary aim of the study is to compare the survivorship of two types of polyethylene (conventional N2Vac and highly cross-linked X3, both FDA approved via 510k clearance) used in a fixed-bearing total knee system in patients undergoing cemented total knee arthroplasty. Specifically, the primary endpoint will be the revision rate at ten years. These results will be measured through radiographs at each post-operative interval with an independent radiograph review being performed after all patients have reached 7 and 10 year follow-up. Secondary results will also be collected and will focus on disease-specific (Knee Society Scores), global (SF-12), and outcome measures. Radiographic results consisting of standing anteroposterior, lateral and Merchant views of the surgical knee will be recorded and analyzed. Completion of the initial investigation will occur at the 10-year interval after the last enrolled patient.

• Study Type: Interventional
• Enrollment (Actual): 518
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Arizona
    • Phoenix, Arizona, United States, 85054
      • Mayo Clinic
  • Florida
    • Jacksonville, Florida, United States, 32224
      • Mayo Clinic
  • Minnesota
    • Rochester, Minnesota, United States, 55905
      • Mayo Clinic

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 21 years to 85 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

INCLUSION CRITERIA:

1. Subjects willing to sign the informed consent.
2. Subjects able to comply with follow-up requirements including post-operative weight bearing restrictions and self-evaluations.
3. Male and non-pregnant female subjects ages 21-85 years of age at the time of surgery.
4. Subjects requiring a primary total knee replacement.
5. Subjects with a diagnosis of osteoarthritis (OA), traumatic arthritis (TA), or avascular necrosis (AVN).
6. Subjects with intact collateral ligaments as determined by the surgeon investigator.

EXCLUSION CRITERIA:

1. Subjects with inflammatory arthritis.
2. Subjects with a history of total or unicompartmental reconstruction of the affected joint.
3. Subjects that have had a high tibial osteotomy or femoral osteotomy.
4. Subjects with neuromuscular or neurosensory deficiency, which would limit the ability to assess the performance of the device.
5. Subjects with a systemic or metabolic disorder leading to progressive bone deterioration.
6. Subjects that are immunologically compromised, or receiving chronic steroids (>30 days).
7. Subjects bone stock is compromised by disease or infection that cannot provide adequate support and/or fixation to the prosthesis.
8. Subjects with knee fusion to the affected joint.
9. Subjects with an active or suspected latent infection in or about the knee joint.
10. Subjects that are prisoners.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Control; Stryker Orthopaedics N2Vac Polyethylene when used with a Triathlon Posterior Stabilized total knee system. This is a fixed- bearing knee intended for use in patients undergoing cemented total knee arthroplasty.	Device: N2Vac Polyethylene; Ultra-high-molecular-weight polyethylene (UHMWPE).; Other Names: N2Vac
Experimental: Treatment; Stryker Orthopaedics X3 Polyethylene when used with a Triathlon Posterior Stabilized total knee system. This is a fixed- bearing knee intended for use in patients undergoing cemented total knee arthroplasty.	Device: X3 Polyethylene; Highly cross-linked polyethylene (HXLPE).; Other Names: X3

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Prosthesis Survivorship Free of Revision	The survival of prostheses free of revision 10 years post operation.	From operation to 10 years post-operative

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Prosthesis Survivorship Free of Reoperation	The survival of prostheses free of reoperation 10 years post operation.	From operation to 10 years post-operative
Prosthesis Survivorship Free of Complications	The survival of prostheses free of related complications (non-operative) 10 years post operation.	From operation to 10 years post-operative
Knee Society Score (KSS)	The KSS evaluates pain, stability and range of motion. The scale ranges between scores of 0-100. The maximum score of 100 points is reached when there is no pain, with good alignment of the knee in extension, and at least 125° of range of motion, without any anteroposterior or mediolateral instability. Deductions are made for flexion contracture, loss of extension and poor alignment. Higher scores indicate better knee conditions, while lower scores indicate worse knee conditions.	Pre-operative (baseline) and 10-years post-operative
Knee Society Score (KSS): Function	The Function KSS evaluates the walking distance and the act of climbing and descending stairs. The scale ranges between 0-100. The maximum score of 100 points is attributed to the individual capable of walking unlimited distances without walking aids, and of climbing and descending stairs normally. Deductions are made for the use of canes, crutches or walking frame. Higher scores indicate better knee conditions, while lower scores indicate worse knee conditions.	Pre-operative (baseline) and 10-years post-operative
12-Item Short Form Health Survey (SF-12): Mental Health Score	The SF-12 questionnaire uses questions selected from the longer SF-36 Health Survey to measure patient wellness and quality of life. The scoring algorithm is calibrated so that an average healthy person would have a t-score of 50 points with a standard deviation of 10. Higher scores indicate better mental health.	Pre-operative (baseline) and 10-years post-operative
12-Item Short Form Health Survey (SF-12): Physical Health Score	The SF-12 questionnaire uses questions selected from the longer SF-36 Health Survey to measure patient wellness and quality of life. The scoring algorithm is calibrated so that an average healthy person would have a t-score of 50 points with a standard deviation of 10. Higher scores indicate better physical health.	Pre-operative (baseline) and 10-years post-operative
Comparison of Radiographic Success/Failure Between Groups	Radiographic review for success and or failure of the TKA prostheses at 10 years post-operation. A migrating or shifting prosthesis with or without the disappearance of radiolucent lines is considered a failure.	10 years post-operative

Collaborators and Investigators

• Sponsor: Mayo Clinic
• Collaborators: Stryker Orthopaedics
• Investigators: Principal Investigator: Matthew Abdel, MD, Mayo Clinic

Publications and helpful links

Helpful Links

• Mayo Clinic Clinical Trials

Study record dates

Study Major Dates

• Study Start: February 1, 2007
• Primary Completion (Actual): November 1, 2023
• Study Completion (Actual): November 1, 2023

Study Registration Dates

• First Submitted: June 26, 2007
• First Submitted That Met QC Criteria: June 26, 2007
• First Posted (Estimated): June 28, 2007

Study Record Updates

• Last Update Posted (Actual): November 6, 2024
• Last Update Submitted That Met QC Criteria: October 14, 2024
• Last Verified: October 1, 2024

More Information

Terms related to this study

• Other Study ID Numbers: 06-003093

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes