Politecnico di Torino

M. Terzini, E.M. Zanetti, A.L. Audenino, L. Gastaldi, S. Pastorelli, E. Panero, A. Sard and C. Bignardi

Dept. of Mechanical and Aerospace Engineering, Politecnico di Torino, Torino, Italy

Dept. of Engineering, University of Perugia, Perugia, Italy

Hand Surgery Division, AOU CTO, Torino, Italy

In this work, a multibody model consisting of bones and ligamentous structures is presented. A multibody model was created in ADAMS (MSC Software Corporation, Santa Ana, CA) by importing the CAD geometries of humerus, ulna and radio, pre-assembled in the extended position. Ligaments and intraosseous membrane were then modelled as non-linear springs thanks to the implementation of user define functions. Humerus-ulna, humerus-radio and ulna-radio contact forces were defined through an impact formulation describing the contact force as a function of the interpenetration between bodies and the interpenetration velocity. To validate the model the experimental maneuvers were recreated imposing an axial compression along the ulnar axis at 30°, 60° and 90° of flexion. A set of markers were placed on the medial side of the elbow joint to measure the joint gaps. Results were compared to the experimental outcomes. The high similarity between the model results and the experimental measurements suggests the capabilities of the multibody framework in the quantitative evaluation of anatomical and physiological parameters.