Design of the prosthetic socket and the finite element analysis of the interfacial stress / 中国组织工程研究

ABSTRACT

BACKGROUND: Biomechanical properties of the residual limb-socket interface not only have a direct impact on the fit of the prosthesis, but also the basis for optimal design of the socket structure. Combining digital design technology with rehabilitation medical engineering will effectively improve the efficiency and quality of the prosthesis socket. OBJECTIVE; The reverse-positive combined modeling method was used to design a custom-made socket model for patients with calf amputation to evaluate the interfaciai stress between the residual limb and the socket. The socket was iteratively designed. The optimized model was produced by three-dimensional printing to improve traditional hand-made socket methods. METHODS: Two patients with calf amputation were selected (Volunteers of the Inner Mongolia Honorary Military Rehabilitation Center). According to the CT scan image of the patient’s residual limb, Mimics was used for image processing, and then Geomagic and UG were used to obtain the geometric model of the residual limb. Through the use of the computer-aided design software Fusion360, the socket was forward modeled according to the different tolerances of the tissue structure of the various parts of the residual limb. The Mooney-Revlin superelastic model was used to define the material properties of the soft tissue, and the finite element analysis of the residual limb-socket interface stress was performed. The iterative design of the socket was carried out according to the feedback of the results, and the acceptance socket model after re-modification was evaluated. Three-dimensional printing produced a socket, which received experimental measurements. RESULTS AND CONCLUSION: (1) The stress of the interface between the socket and the residual limb after iterative design was analyzed, and the stress values of the residual limbs were lower than the pain threshold, which met the design standard and could achieve functional transferability and safety comfort. (2) Two patients wearing three-dimensional printing made the socket adaptability and stability, and the walking symmetry was significantly improved compared with the hand-made socket, meeting the biomechanical requirements of the residual limb. (3) A complete design, evaluation and manufacturing system for the prosthetic lumen was established.