A new sequential approach to the modelling of human diarthrodial joints

The basic role played by models of the diarthrodial joints in surgery, in pre-surgical planning and in prosthesis design has been widely stressed in the literature. Different approaches have been proposed in order to highlight the role of the main anatomical structures of the joint. Most models are based on in vivo measurements which, however, are difficult to perform. This paper presents a sequential procedure based on three steps for the modelling of a joint. At each step a more and more complicated model of the joint is provided. Starting with a limited number of the passive anatomical structures of the joint (ligaments, for instance), all the structures, both passive and active (muscles), are incorporated in the final model step by step. This procedure makes it possible to progressively gain a deeper understanding of each structure of the joint. Examples of application to the knee and ankle joints are finally reported, which show the potential of the sequential procedure proposed in this paper.