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.
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
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
518
Highly cross-linked polyethylene (HXLPE).
Ultra-high-molecular-weight polyethylene (UHMWPE).
Mayo Clinic
Phoenix, Arizona, United States
Mayo Clinic
Jacksonville, Florida, United States
Mayo Clinic
Rochester, Minnesota, United States
Prosthesis Survivorship Free of Revision
The survival of prostheses free of revision 10 years post operation.
Time frame: From operation to 10 years post-operative
Prosthesis Survivorship Free of Reoperation
The survival of prostheses free of reoperation 10 years post operation.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: Pre-operative (baseline) and 10-years post-operative
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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.
Time frame: 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.
Time frame: 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.
Time frame: 10 years post-operative