Advance® Medial Pivot人工膝関節の運動解析

In Vivo Fluoroscopic Analysis of the Advance® Medial Pivot Arthroplasty

　Advance^® Medial Pivot人工膝関節は，medial pivot運動および正常膝のkinematicsの再現を目指している．今回は，この人工関節における荷重時の運動解析を行った．対象は変形性関節症8例8膝とし，階段昇降動作を行わせ，イメージマッチング法による3次元画像解析システムを使用し計測した．回旋においては全例にmedial pivot patternを認め，本機種の特徴であるmedial pivot motionの再現という観点からは目的を果たしていると考えられた．

　The Advance^® Medial Pivot total knee design features the ability to achieve normal medial pivot motion by creating a unique ball-in-socket interface on the medial side. The purpose of the current study was to analyze the weight-bearing kinematics of the Advance^® Medial Pivot knee implant. In vivo kinematics were measured for 8 clinically successful total knee arthroplasties during a stair-climbing activity using lateral fluoroscopy and shape matching techniques. All 8 patients were diagnosed as having primary osteoarthritis of the knee. The mean follow-up period was 14 months. All patients showed similar medial pivot motions with minimal movement of the medial condyle during a stair-climbing activity. The lateral condyle was gradually translated posteriorly by 20 degrees. These data suggest that the Advance^® Medial Pivot total knee arthroplasty shows medial pivot motion during a stair-climbing activity.