Design procedure and rules to configure lower limb prosthesis

Modular lower limb prosthesis is composed by custom-fit parts, such as the socket containing the residual limb, and standard components available on market, such as knee or foot. For both custom and standard parts the support offered by existing design tools is not efficient or integrated enough and, as a result, most prosthetists do not use computer-aided tools and still rely only on their personal expertise. This paper presents an approach to design and configure complete lower limb prosthesis for transfemoral and transtibial amputees, using patient’s digital data (e.g., residual limb model acquired by MRI) and specification sheets of components. The ultimate goal is to realise a virtual laboratory where the technicians can design lower limb prosthesis guided step by step by the system. We have identified key patient’s characteristics guiding the prosthetist during the four main steps of the production process: acquiring patient’s data, socket modelling, standard components selection and prosthesis assembly and check. The developed innovative framework integrates different tools to guide the technicians during each design task providing specific knowledge and rules. Thus, it allows a quicker and easier definition of the virtual prosthesis, on which virtual test could be performed (e.g., pressure distribution on residual limb, gait evaluation) in order to be able to realize the definitive prosthesis at the first attempt. The results have been evaluated and validated with the technical staff of a certified orthopaedic laboratory.