First approach to unilateral transfemoral amputees' contact mechanics

Abstract

The stresses in the hip area have great importance because of their relationship to the health of the joint. Finite element models can predict contact between cartilages, however, contact patterns in unilateral transfemoral amputees have not yet been found in literature. We thus want to present an initial approach in the contact mechanics of the hip joint of these amputees. From an existing database, three transfemoral amputees who use prostheses were chosen. Their respective hips and femur were obtained from tomography, and so as their cartilages from their respective articular surfaces. Finite element models were created per patient and static bipedestation was analyzed. At the beginning of contact between cartilages, contact stresses were determined. The results showed that the stresses of the amputated side were higher than that of the non-amputated, in terms of average and peak contact stress. These were located in the anterior and superior zones, respectively.

Los esfuerzos en la cadera son de gran importancia debido a su relación con la salud articular. Modelos de elementos finitos pueden predecir el contacto entre cartílagos, sin embargo, modelos de contacto en amputados transfemorales unilaterales, no han sido encontrados aún en la literatura. Se quiere presentar un acercamiento inicial en la mecánica de contacto de la articulación coxofemoral de dichos pacientes. De una base de datos existente, se eligieron tres amputados transfemorales usuarios de prótesis; se obtuvieron sus respectivas caderas y fémures a partir de tomografía, y los cartílagos de las respectivas superficies articulares. Se crearon modelos por elementos finitos por paciente y se analizó la bipedestación estática. Se determinaron los esfuerzos al inicio del contacto articular, observando resultados mayores para el lado amputado, tanto para los esfuerzos promedio como para los esfuerzos máximos de contacto; y estos se encontraron en la zona anterior y superior respectivamente.