Estudo da remodelação óssea no úmero após uma artroplastia do ombro

Carlos Miguel Fernandes Quental

Key information

Authors:

Carlos Miguel Fernandes Quental (Carlos Quental)

Supervisors:

Paulo Rui Alves Fernandes (Paulo Rui Alves Fernandes); João Orlando Marques Gameiro Folgado (João Orlando Marques Gameiro Folgado)

Published in

11/04/2008

Abstract

In this work computational models are developed to analyze bone remodelling of the humerus after a shoulder arthroplasty using either a cemented or press-fit stem. Bone is modelled as a porous material, characterized by its local density. The bone remodelling model is based on a global optimization criterion by the minimization of a function which takes into account both structural stiffness and the metabolic cost related with bone maintenance, by the use of a biomechanical parameter k that varies with different biological factors. The most suitable value for the biomechanical parameter k is chosen based on the analysis of three-dimensional models of the humerus without the implant, in order to achieve the one which best reproduces its real morphology. This way, not only the most appropriate value for k is defined, but also the model is validated, showing its ability to reproduce with high similarity the real morphology of bone. After the determination of the biomechanical parameter k, the bone remodelling model was applied to three-dimensional models of the implanted humerus, starting with the same density distribution as the obtained previously with the model of the humerus without the implant, being thus closer to reality. The results obtained, in general, do not show significant changes of the bone mass, which leads to the conclusion that stress shielding and the resulting bone remodelling do not play a major role in the failure of shoulder prosthesis.