摘要
Abstract
Objective To analyze the influence of material properties of liners on pressure distribution between residual limb and socket during the stance phase, which provides reference for the fitting scheme of liners for trans-femoral prosthesis. Methods CT images of stump and socket were obtained with computer tomography technology,and 3D models were obtained with information science and engineering methods,such as socket, liner, amputation, bones. Then we adjusted the models according to the changes of hip joint in stance phase, obtained the assemble model of phases of initial contact, loading response, mid-stance, terminal stance,pre-swing. We analyzed the assemble models with nonlinear finite element methods according to the measured results of ground reaction force and the changes of hip joint through Motion and Kistler. On this basis,we simulated the influence of material properties of the liners on the equivalent stress and the maximum shear stress distribution between stump and socket. Results With different liner elastic modulus,the maximum equivalent stress and shear stress of stump appeared in the medial residual limb and in the position of the residual limb corresponding to the edge of socket in phases of initial contact,loading response,mid-stance, and terminal stance. The maximum equivalent stress and shear stress of stump appeared in the medial residual limb,in the position of the residual limb corresponding to the edge of socket and around the ischium in phase of pre-swing. When the elastic modulus of the silicone liner changed at the range of 0.98 MPa to 2.70 MPa, the equivalent stress was in the range of 13.85 kPa to 23.55 kPa,and the shear stress was in the range of 7.82 kPa to 13.46 kPa in phase of pre-swing, while the other phases were basically the same. Conclusions The mechanical properties of silicon liners affect the pressure distribution of the interface between residual limb and socket,the maximum equivalent stress and shear stress of stump vary greatly during the pre-swing period. We should pay more attention to the process of prosthesis fitting.关键词
大腿假肢/应力分布/硅胶套/步态/有限元分析Key words
trans-femoral prosthesis/pressure distribution/silicone liner/gait/finite element analysis分类
医药卫生
