Research Of Personalized Prosthetic Socket Design Based On 3D Reconstruction

With the development of the economy and society,the requirements for the comfort of the socket are increasing.In order to make the amputation patient wear the socket more comfortable,reduce the damage to the residual limb,and accelerate the production cycle of the socket,it is very necessary to improve the design method of the prosthetic socket.The study of the biomechanical properties of the residual limb-accepting cavity interface not only directly affects the fit of the prosthesis,but also serves as the basis for optimal design of the socket structure.According to the CT image of the leg amputation patient,the geometric model of bone and soft tissue is obtained by three-dimensional reconstruction.The computer aided design of the socket is performed according to the modification principle.The finite element analysis method was used to study the distribution of normal stress and shear stress at the residual cavity-socket in the standing state.Then,according to the feedback guidance of the finite element results,the socket was iteratively designed and evaluated again,and finally the energy was obtained.A well-accepted cavity model that achieves functional transferability and safety comfort.The main contents and conclusions of the paper are as follows:(1)The CT scan data of the patient’s residual limb was imported into the medical image processing software Mimics for processing,and the geometric model of the femur,tibia and soft tissue of the residual limb was obtained through three-dimensional reconstruction of Geomagic and UG.(2)Through the use of computer-aided design technology,according to the different structural tolerance of the various parts of the residual limb as the modification principle,the forward cavity is designed for forward modeling.(3)The Mooney-Revlin superelastic model was used to define the material properties of soft tissue,and the distribution of normal and shear stress at the residual limb-socket was observed by finite element analysis.The use of superelastic materials to define the material properties of soft tissue can better simulate the nonlinear characteristics of the system and the large deformation of the contact surface of the residual limb,and improve the reliability of the finite element analysis results.(4)According to the feedback guidance of finite element results,the iterative design of the socket is carried out,and the interface stress of the socket and the residual limb after re-shaping is analyzed,and the stress distribution on the surface of the residual limb and the calculation result of the reference literature are basically obtained.Consistently,the stress values of the soft tissue of the residual limb were lower than the pain threshold,which met the design criteria.Finally,a receiver cavity model that achieves better functional transferability and safety comfort is obtained.(5)According to the results of human gait analysis,the distribution of normal stress at the interface of the residual limb-socket system during the gait cycle and the variation law under each phase are obtained by finite element analysis.In this paper,the inverse positive combination modeling method is used to iteratively design the socket,and the feedback guidance is based on the finite element results.Finally,the designed socket model can be quickly manufactured by 3D printing to obtain the socket entity,compared with the existing research.It is only through the forced displacement of the node in the finite element software to realize the modification of the socket,and it has direct clinical use value.The design and evaluation system for the calf prosthesis socket was established,and the digital technology and rehabilitation medical engineering were combined to effectively improve the production efficiency and quality of the prosthetic socket.