Document Type

Dissertation

Date of Degree

Spring 2013

Degree Name

PhD (Doctor of Philosophy)

Degree In

Biomedical Engineering

First Advisor

Thomas D. Brown

Abstract

Total hip arthroplasty (THA) is the treatment of choice to relieve joint pain and loss of mobility as a result of advanced stage osteoarthritis or other hip pathologies. Despite their general success, THAs do fail, with revision rates estimated near 5% per year. Instability, defined as the complete subluxation (dislocation) of the femoral head from the acetabular socket - which usually occurs due to implant impingement - has recently supplanted wear-induced osteolytic aseptic loosening as the leading cause of failure in THA. Soft tissue integrity has long been recognized as influencing joint stability, and therefore there has been great interest recently in improving soft tissue restoration following THA. However, there is little quantitative information related to the degree of soft tissue repair necessary to restore joint stability. Additionally, impingement events, besides their role in prelude to frank dislocation, hold potential to damage new-generation hard-on-hard bearings, due to the relatively unforgiving nature of the materials and designs. Despite the largely biomechanical nature of these impingement-related complications, they remain under-investigated relative to their burden of morbidity. In addition to impingement, failure modalities unique to hard-on-hard bearings merit careful biomechanical scrutiny. This includes investigation of catastrophic fracture in ceramic-on-ceramic bearings, as well as analysis of patient, implant and surgical variables associated with increased wear and adverse soft tissue engagement potential for metal-on-metal implants. Toward the goal of improving current biomechanical understanding of failure modalities in THA and to provide an objective basis for orthopaedic surgeons to choose the most favorable implants and to identify optimal intraoperative parameters which minimize failure propensity, a novel, anatomically-grounded finite element model was developed, and used to perform multiple parametric finite element investigations of these failure modes.

Keywords

Biomechanics, Total hip arthroplasty

Pages

xxiii, 197 pages

Bibliography

Includes bibliographical references (pages 176-197).

Comments

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Copyright

Copyright 2013 Jacob Matthias Elkins

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