DOI

10.17077/etd.qmxgsc4j

Document Type

Thesis

Date of Degree

Fall 2017

Access Restrictions

Access restricted until 01/31/2019

Degree Name

MS (Master of Science)

Degree In

Biomedical Engineering

First Advisor

Jessica E. Goetz

First Committee Member

Donald D Anderson

Second Committee Member

Nicole M Grosland

Third Committee Member

David G Wilder

Fourth Committee Member

Michael C Willey

Abstract

Acetabular dysplasia, a deformity characterized by the presence of a shallow acetabulum inadequately covering the femoral head, alters force transfer through a joint, causing early-onset hip pain and degeneration. Dysplasia is often treated surgically with a periacetabular osteotomy (PAO), which permits multiplanar acetabular reorientation to stabilize the joint and alleviate pain. PAO alters joint mechanics, including contact stress, which can be assessed via computational methods.

This work sought to enhance a discrete element analysis (DEA) model for assessment of the dysplastic hip. The primary focus was on understanding how the gait parameters used to load a DEA model affect the computed contact stress. Several additional studies focused on understanding specific anatomic and demographic factors contributing to the contact stress evaluation were also performed.

Implementation of a dysplastic gait pattern to load the DEA models resulted in more cases with improved contact stress and clinical measures after PAO, which concurred with clinical findings. Patient demographics and acetabular and femoral geometry all affected the computed contact stress distributions, emphasizing the importance of proper cohort categorization prior to interpretation of DEA-calculated contact stress. These results indicate that accurate modeling of the particular deformity in this cohort likely requires evaluation of both functional and anatomic differences.

These studies improve the ability to realistically model and characterize dysplastic hip contact mechanics. DEA is a valuable tool for assessing contact stress in dysplastic joints, which has the potential to improve patient outcomes by guiding clinicians in non-operative treatment, pre-operative PAO planning, and evaluating intraoperative success.

Keywords

Contact Stress, Discrete Element Analysis, Dysplasia, Gait, Hip, Periacetabular Osteotomy

Pages

xii, 102 pages

Bibliography

Includes bibliographical references (pages 96-102).

Copyright

Copyright © 2017 Holly Dominique Thomas

Available for download on Thursday, January 31, 2019

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