A prospective, randomized, single-blinded clinical trial is proposed to compare a mobile-bearing total knee system with two types of fixed-bearing total knee systems in patients undergoing cemented total knee arthroplasty. The devices to be used are FDA approved: the Sigma Knee System (mobile-bearing), the Sigma, Pressfit Condylar posterior cruciate substituting (fixed-bearing) system with a metal backed tibial tray, and the Sigma press-fit condylar posterior cruciate substituting system (fixed bearing) with an all polyethylene tibial tray.
Eighty cases will be assigned to each arm of the study. Each patient will be assessed two months after surgery, one year after surgery, two years after surgery, five years after surgery, and every three to five years thereafter. The principal outcome measures will be the Knee Society Clinical rating scale and the SF-12. The result for these will be analyzed using students' t-test analysis, taking into account classification by demographic variables. Chi-square analysis will be used to compare the instance of mortality, revision surgery, deep vein thrombosis, pulmonary embolus, neurovascular complication, and infection. Other outcome measures incorporated in the Knee Society Clinical rating scale will undergo appropriate generalized linear regression for the type of outcome involved.
Primary Outcome Measures:
- The primary aim of the study is to compare the results of a mobile-bearing total knee system with a fixed-bearing total knee system in patients undergoing cemented total knee arthroplasty. [ Time Frame: 2 months; 1, 2 and 5 years ] [ Designated as safety issue: No ]
Enrollment: |
240 |
Study Start Date: |
January 2001 |
Estimated Primary Completion Date: |
January 2009 (Final data collection date for primary outcome measure) |
1: Active Comparator
80 patients receiving the Sigma Knee System (mobile-bearing knee with the P.S. polyethylene insert)
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Device: Sigma Knee System
Sigma Knee System (mobile-bearing knee with the P.S. polyethylene insert)
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2: Active Comparator
Sigma Pressfit Condylar Posterior Cruciate Substituting System with a metal back tilbial tray (fixed-bearing knee with the metal backed tray)
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Device: Sigma Pressfit Condylar Posterior Cruciate Substituting System
Sigma Pressfit Condylar Posterior Cruciate Substituting System with a metal back tilbial tray (fixed-bearing knee with the metal backed tray)
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3: Active Comparator
Sigma Pressfit Condylar Posterior Cruciate Substituting System (fixed bearing with an all polyethylene tray)
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Device: Sigma Pressfit Condylar Posterior Cruciate Substituting System all polyethylene tray
Sigma Pressfit Condylar Posterior Cruciate Substituting System (fixed bearing with an all polyethylene tray)
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Pain, weakness, instability, and progressive dysfunction are the hallmarks of arthritis of the knee. Total knee replacement may frequently be the only therapeutic intervention to provide adequate improvement in pain and function. Both fixed bearing and mobile bearing knees have a long track record of clinical success. Mobile bearing designs have theoretical advantages of decreased contact stresses on the tibial tray, decreased polyethylene wear, and improved range of motion relative to fixed bearing designs. These theoretical advantages may become especially important in the young patient who requires a knee arthroplasty. This study will attempt to see if there is a clinical difference in outcome between mobile bearing and fixed bearing knee arthroplasties in patients who require knee arthroplasty.