Date of Award

Summer 2017

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Mechanical & Aerospace Engineering

Committee Director

Stacie I. Ringleb

Committee Member

Sebastian Y. Bawab

Committee Member

Gene Hou

Abstract

Computational modeling of joints is used to investigate the effect of injuries, to plan surgeries, and to answer questions about joints that cannot be answered experimentally. Existing models of the ankle joint are moving toward being able to model specific patients, however, they do not include all of the anatomy (e.g., bones and/or ligaments) and have restrictive boundary conditions. These simplification in anatomy are made to minimize pre-processing and computation time. Because biomechanical modeling is increasingly focused on the implementation of patient specific cases, the effects of including more anatomical structures and determining how they affect the model results is necessary. Therefore, the purpose of this study was to develop a 3D Finite Element (FE) model of the ankle joint complex (i.e., tibia, fibula, talus, and calcaneus) with 13 major ligaments, and to determine how modeling the structure of the ligaments and the number of bone affected the contact stress in the talocrural joint (i.e., the joint between the tibia/fibula and the talus). A finite element model was developed in FEBio (FEBio, Salt Lake City, UT) from the CT data obtained from one cadaver. The model included bones, cartilage, and ligaments. Ligaments were modeled as tension-only linear springs, and applied for more than one spring for each of 13 major ligaments. Morphology of the spring was set as parallel or X configuration. The stress in the joint between the tibia and talus showed differences with the different number of bones. Especially, the stress of the three bone FE model was higher than ankle complex configuration with the same number of ligaments. The stresses were measured in Talocrural Joint 2 including tibia, talus, and 6 springs and Talocrural Joint 3 including tibia, talus, fibula, calcaneus, and 12 springs from 2.0541 MPa to 2.3077 MPa. The big difference between the models was the existence/non-existence of calcaneus. It demonstrates that the stress contour of Talocrural Joint 3 was had the most similar pattern with the Novel pressure data obtained from experiment.

ISBN

9780355407952

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