Analysis of a below-knee patellar tendon-bearing prosthesis: a finite element study.
Analysis of a below-knee patellar tendon-bearing prosthesis: a finite element study.
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膝下髌腱支撑假体的分析：有限元研究。
DOI：
10.1682/jrrd.1991.07.0001
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发表时间：
1991
影响因子：
--
通讯作者：
Harry B. Skinner
中科院分区：
文献类型：
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作者：
Peter M. Quesada;Harry B. Skinner
在本研究中，构建了髌骨肌腱支承（PTB）设计的膝下假体的有限元（FE）模型，以及该模型的几种更改变体。在模型的脚跟处施加约1.5倍正常体重（984 N）的载荷，以模拟脚跟着地条件。然后对“基础”模型进行分析和迭代修改，直到开发出一个提供软组织弹性模量和窝位移之间一致性的模型。从该修订后的基础模型分析中获得的界面法向应力和剪切应力在窝/残端的远端前尖端处最高（分别约为961和463 KPa）。在近端，内侧和后侧发现较高的正常应力（72-78 KPa）。近端剪切应力最高的后方（79 KPa），虽然剪切应力内侧（51 KPa），外侧（43 KPa），也远远高于前方（10 KPa）。对改变后的模型进行有限元分析，以确定改变假体有限元模型对接受腔/残端界面应力的相对影响。分析结果表明，用弹性模量比修改后的基础模型低10倍的材料制造假体，可以使最大压力降低14%。最大压力大幅下降（71%）是由于使用了吸力插座而不是传统插座。残端长度的微小变化（2厘米）引起相对较大的压力变化（16%至18%）。
In this study, a finite element (FE) model of a below-knee prosthesis of patellar tendon-bearing (PTB) design, and several altered variations of the model have been constructed. A load of approximately 1.5 times normal body weight (984 N) was applied at the heel of the model to simulate heelstrike conditions. The "base" model was then analyzed and revised iteratively until a model which provided consistency between soft tissue elastic modulus and socket displacement was developed. The interface normal and shear stresses obtained from the analysis of this revised base model were highest (about 961, and 463 KPa, respectively) at the distal anterior tip of the socket/stump. Proximally, higher normal stresses (72-78 KPa) were found medially and posteriorly. Proximal shear stresses were highest posteriorly (79 KPa), although shear stresses medially (51 KPa), and laterally (43 KPa), were also much higher than anteriorly (10 KPa). FE analyses were performed on the altered models to determine the relative effects on socket/stump interface stresses of altering the FE model of the prosthesis. Results of the analysis indicate that fabricating the prosthesis from a material with an elastic modulus ten times lower than that of the revised base model can produce reductions in the maximum pressure of up to 14 percent. Large decreases in maximum pressures (71 percent) resulted from the use of a suction socket rather than a conventional socket. Small changes in stump length (2 cm) caused relatively large pressure changes (16 to 18 percent).