内骨架一体化小腿假肢的生物力学研究

Biomechanical Research on Endo-skeletal Trans-tibial Monolimb

一体化假肢是以聚合物为材料从接受腔到假腿一体成型的新型下肢假肢 ,它比传统型假肢更经济、美观、轻便 ,具有较大的应用前景。目前的相关研究主要集中在设计与制作及少量的临床研究方面。由于一体化假肢与传统型假肢在结构上的差异 ,有必要对其进行应力分析。本研究的目的是开展内骨架一体化假肢的生物力学研究 ,本研究基于内骨架一体化小腿假肢的真实几何构型 ,建立三维有限元模型 ,计算该模型在模拟HeelOff步态时相的载荷作用下的应力分布 ;在保持该模型的几何形状不变的情况下 ,建立了三个不同壁面厚度的一体化小腿假肢的有限元模型 ,分析壁面厚度对一体化小腿假肢应力分布的影响 ;通过分别赋予模型四种不同高分子聚合物的材料力学特性值 ,分析不同材料的一体化假肢的应力分布特点 ;分别对模型施加与正常步态的五个典型时相对应的载荷 ,分析一体化小腿假肢在各步态时相的应力分布特点。本研究结果对一体化假肢设计有指导价值。

Monolimb is a new type of lower-limb prostheses made of polymerie materals, in which the socket and prosthetic shank are integrative. Compared with traditional prosthesis, monolimb is more economical, good-looking and portable, so it indicates a potential application in the future. So far the related research mainly focused on the fabrication, CAD/CAM, or clinical test. Because of the structural difference between monolimb and traditional prosthesis, biomechanical research on trans-tibial monolimb is necessary and helpful. In this article, a 3D FE model based on real geometry shape of an endoskeletal trans-tibial monolimb was established. The stress distribution was obtained under the load corresponding to the subphase of stance of Heel Off. Keeping the same geometrical shape, 3D FE models of transtibial monolimbs with different wall thickness are established. The influence of wall thickness on the stress distribution was analyzed. The influence of mechanical property of four kinds polymerie materiels on stress distribution was studied. Also the stress distributions were given under the loads of five typical subphases of stance respectively. The results and conclusions in this article are expected to be valuable for improving the design of monolimb.