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Completed

NCT Number: NCT00493792

X-3 Polyethylene Survival Outcomes Study

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.

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Key information

Conditions

Arthroplasty, Replacement, Knee Total Knee Replacement

Age range

21 year–85 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Mayo Clinic, Phoenix, Arizona, United States

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About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

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

Exclusion criteria

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

Treatment and study plan

X3 Polyethylene

Device

Highly cross-linked polyethylene (HXLPE).

Other names: X3

N2Vac Polyethylene

Device

Ultra-high-molecular-weight polyethylene (UHMWPE).

Other names: N2Vac

Primary outcomes

  1. Prosthesis Survivorship Free of Revision

    Time frame: From operation to 10 years post-operative

    The survival of prostheses free of revision 10 years post operation.

Secondary outcomes

  1. Prosthesis Survivorship Free of Reoperation

    Time frame: From operation to 10 years post-operative

    The survival of prostheses free of reoperation 10 years post operation.

  2. Prosthesis Survivorship Free of Complications

    Time frame: From operation to 10 years post-operative

    The survival of prostheses free of related complications (non-operative) 10 years post operation.

  3. Knee Society Score (KSS)

    Time frame: Pre-operative (baseline) and 10-years post-operative

    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.

  4. Knee Society Score (KSS): Function

    Time frame: Pre-operative (baseline) and 10-years post-operative

    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.

  5. 12-Item Short Form Health Survey (SF-12): Mental Health Score

    Time frame: Pre-operative (baseline) and 10-years post-operative

    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.

  6. 12-Item Short Form Health Survey (SF-12): Physical Health Score

    Time frame: Pre-operative (baseline) and 10-years post-operative

    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.

  7. Comparison of Radiographic Success/Failure Between Groups

    Time frame: 10 years post-operative

    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.

Sponsors and collaborators

Lead sponsor

Mayo Clinic

Other

Collaborators

  • Stryker Orthopaedics

Registry information

Official study title

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.

Important dates

Study start
2007
Primary completion
2023
Study completion
2023
First posted
Jun 28, 2007
Registry last updated
Nov 6, 2024

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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