In vivo medial and lateral tibial loads during dynamic and high flexion activities
In vivo medial and lateral tibial loads during dynamic and high flexion activities
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DOI：
10.1002/jor.20362
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发表时间：
2007-05-01
影响因子：
2.8
通讯作者：
Fregly, Benjamin J.
中科院分区：
文献类型：
--
作者：
Zhao, Dong;Banks, Scott A.;Fregly, Benjamin J.
尽管全膝关节置换术的内侧和外侧间室之间的不对称载荷可能导致植入物松动和失效，但动态日常活动期间的体内贴靠力分布仍然未知。本研究报告了对线良好的膝关节植入物在各种活动中所经历的体内内侧和外侧接触力。从进行跑步机步态（手放在扶手上）、上/下步、弓步和跪姿活动的单膝关节置换患者中收集体内植入物运动和总轴向载荷数据。使用视频荧光透视测量体内运动，同时使用内固定胫骨部件收集体内轴向载荷。采用线性和非线性聚乙烯材料特性构建弹性基础接触模型，根据测得的运动学、总轴向载荷和压力中心计算内侧和外侧接触力。对于所有活动，预测的内侧和外侧接触力对选定的材料模型不敏感。内侧贴靠力占总贴靠力的百分比范围为：步态18 - 60，上/下步47 - 65，跪和弓步55 - 60。在运动周期中的最大载荷下，步态的内侧力为1.2 BW，上下步的内侧力为2.0 BW，而相应的外侧力分别为1.0和1.5 BW。在最终静态姿势的平均载荷下，膝关节内侧力为0.2 BW，弓步为0.9 BW，相应的外侧力分别为0.1和0.7 BW。对于该患者，在加载活动期间，55%内侧-45%外侧的恒定载荷分配将是这些测试条件的合理近似值。(c)2007骨科研究学会。
Though asymmetric loading between the medial and lateral compartments of total knee replacements may contribute to implant loosening and failure, the in vivo contact force distribution during dynamic daily activities remains unknown. This study reports in vivo medial and lateral contact forces experienced by a well-aligned knee implant for a variety of activities. In vivo implant motion and total axial load data were collected from a single knee replacement patient performing treadmill gait (hands resting on handlebars), step up/down, lunge, and kneel activities. In vivo motion was measured using video fluoroscopy, while in vivo axial loads were collected simultaneously using an instrumented tibial component. An elastic foundation contact model employing linear and nonlinear polyethylene material properties was constructed to calculate medial and lateral contact forces based on the measured kinematics, total axial loads, and centers of pressure. For all activities, the predicted medial and lateral contact forces were insensitive to the selected material model. The percentage of medial to total contact force ranged from 18 to 60 for gait, 47 to 65 for step up/down, and 55 to 60 for kneel and lunge. At maximum load during the motion cycle, medial force was 1.2 BW for gait and 2.0 BW for step up/down, while the corresponding lateral forces were 1.0 and 1.5 BW, respectively. At mean load in the final static pose, medial force was 0.2 BW for kneel and 0.9 BWforlunge, with corresponding lateral forces of 0.1 and 0.7 BW, respectively. For this patient, a constant load split of 55% medial-45% lateral duringloaded activity wouldbe a reasonable approximation for these test conditions. (c) 2007 Orthopaedic Research Society.