Abstract

FLORES RENTERIA, Miguel Ángel  and  AYALA RUIZ, Álvaro. Efectos en la Remodelación Ósea Debido a la Aplicación de Tornillos en Fémur Proximal. Ingenier. mecáni. tecnolog. desarroll [online]. 2012, vol.4, n.2, pp.43-50. ISSN 1665-7381.

The current work describes the alterations that a trabecular bone structure of the proximal femur suffers when long screws are used for fixation, this based in the strain energy density theory. The bone remodeling process initiate with the stimuli generated through the mechanicals loads applied to the bone, this fact determines the change in the bone bulk density and therefore the modulus of elasticity change; this supposes a strength magnitude increment or decrement giving as a result osseointegration or reabsorption respectively in the trabecular bone. A computing tool has been developed using Phyton language and it has been integrated to Abaqus 6.9^®Software. The numerical procedure results let estimate the strength variation and its influence in the bone density final state before and after the screw fixation in the thigh bone, the density patterns obtained let identify quantitatively the zones where the bone-screw interface gets diminished, predicting the density patterns reported in clinical practice, which are only qualitative, furthermore, it is determined that the loss of density during a hundred weeks period is about 45% around the screw, this causes micro-movements generation which results in the screw's fixation loss. Based on the results it is determined that the main factors that affect long screw fixation in thigh bone are: The screw structural stiffness, the diameter, the height and the pitch of the screw thread.

Keywords : Bone remodeling; osseo integration; density patterns; finite element.

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