X-3 Polyethylene Survival Outcomes Study

Not Applicable

Completed

Conditions: Arthroplasty, Replacement, Knee
Total Knee Replacement

Interventions: Device: N2Vac Polyethylene
Device: Stryker X3 Crosslink Polyethylene

Registration Number: NCT00493792

Lead Sponsor: Mayo Clinic

Brief Summary: 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.

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.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 518

Inclusion Criteria

Not provided

Exclusion Criteria

Not provided

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Control	N2Vac Polyethylene	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.
Treatment	Stryker X3 Crosslink Polyethylene	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.

Primary Outcome Measures

Name	Time	Method
Prosthesis Survivorship Free of Revision	From operation to 10 years post-operative	The survival of prostheses free of revision 10 years post operation.

Secondary Outcome Measures

Name	Time	Method
Prosthesis Survivorship Free of Reoperation	From operation to 10 years post-operative	The survival of prostheses free of reoperation 10 years post operation.
Prosthesis Survivorship Free of Complications	From operation to 10 years post-operative	The survival of prostheses free of related complications (non-operative) 10 years post operation.
Knee Society Score (KSS)	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.
Knee Society Score (KSS): Function	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.
12-Item Short Form Health Survey (SF-12): Mental Health Score	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.
12-Item Short Form Health Survey (SF-12): Physical Health Score	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.
Comparison of Radiographic Success/Failure Between Groups	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.