MODELO COMPUTACIONAL DA ARTICULAÇÃO GLENOUMERAL

Resumo

The development of the shoulder model was based on the information acquired from clinical
exams of a subject and from the literature data. The forces acting on the joint are the arm weight, the
muscle forces, the reaction forces due to the muscle wrapping and the joint reaction force. The amplitude
of these forces were obtained from a mathematical approach in which the objective is the determination
of the lowest forces that the muscles should exert to stabilize the glenohumeral joint. These forces were
then applied on the FE model on Abaqus. The analysis was performed in static positions of 0°, 30°, 60°,
90° and 120° of abduction with the arm in 90° of external rotation. The joint reaction force magnitude
increases up to 690 N at 90o of abduction and decreases at 120o, showing the same trend observed in
other studies. The muscle forces are consistent with the information found in the literature, where there
is a high activation of the subscapularis, possibly due to the absence of the passive stabilizers, and the
deltoid. The articular contact center is initially located in the central region of the glenoid cartilage and
moves in the superior-anterior direction up to 60o of abduction, moving then to the central-anterior
region. The maximum contact pressure is observed at the 60o of abduction and the translation of the
humeral head remains within a sphere with a diameter equal to 3.1 mm, whose center coincides with the
center of the articular surface of the glenoid cartilage.