DOI

10.17077/etd.qlotk4el

Document Type

Thesis

Date of Degree

Spring 2017

Degree Name

MS (Master of Science)

Degree In

Biomedical Engineering

First Advisor

John J. Callaghan

First Committee Member

John J Callaghan

Second Committee Member

Nicole M Grosland

Third Committee Member

Jacob M Elkins

Fourth Committee Member

Donald D Anderson

Abstract

Obesity is a severe concern worldwide and its prevalence is expected to continue to increase. Linked to diabetes, kidney disease, heart disease, and high blood pressure among other things, obesity has been identified as the forthcoming, largest preventable cause of mortality. Osteoarthritis, surgical consequences, distribution of subcutaneous adipose tissue, and alteration of joint biomechanics have vast implications in total joint repair (TJR). Previous studies have linked obesity to increased forces through weight-bearing lower extremities, alterations in gait, and risk of implant failure. The objectives of this study were to (1) provide a tool to predict lower extremity dimensions and shape variations of subcutaneous adipose tissue, (2) identify the degree to which obesity influences shape variation of the osseous anatomy of the knee joint, and (3) lay a foundation to compare the knee contact force of obese patients in activities of daily living.

Long-leg EOS films were obtained, retrospectively over 5 years, from 232 patients that were being seen at the Adult Reconstruction Clinic at the University of Iowa. Using custom Matlab algorithms, measurements of soft tissue distribution and lower extremity osseous anatomy were obtained and analyzed. Additionally knee contact force measurements were obtained through motion capture analysis and modeling in Anybody Technology.

Males and females had similar lower extremity shapes, with females having greater knee circumferences than males. The variability of PPT and PTT tended to be greater in females and increased with increasing BMI. Although similar in the anteroposterior direction, males tended to have on average 12mm wider proximal tibias in the mediolateral direction. Clinical observations of increased post-operative complications trend with these findings. The future of research into biomechanics of obesity will rely heavily on anatomic models of the obese lower extremities, which until this work did not exist.

Public Abstract

Obesity is a severe concern worldwide and its prevalence is expected to further increase. Linked to chronic diseases, obesity has been identified as the soon to be largest preventable cause of mortality. Joint pain, surgical consequences, distribution of fat, and alteration of joint biomechanics have vast implications in total joint repair (TJR). Previous studies have linked obesity to increased forces throughout the legs, alterations in gait, and risk of joint replacement failure. The objective of this study was to construct an anatomical modelling library of obese lower extremities and develop a foundation for computation of obese modelling parameters defining activities of daily living.

Long-leg EOS radiograph films were obtained, retrospectively over 5 years, from 232 patients that were being seen at the Adult Reconstruction Clinic at the University of Iowa. Using custom software, measurements of fat distribution and leg boney anatomy were obtained and analyzed. Additionally knee contact force measurements were obtained through motion capture analysis and modeling in Anybody Technology.

Males and females had similar lower extremity shapes, with females having greater knee circumferences than males. The variability of PPT and PTT tended to be greater in females and increased with increasing BMI. Although similar in the anteroposterior direction, males tended to have on average 12mm wider proximal tibias in the mediolateral direction. Clinical observations of increased post-operative complications trend with these findings. The future of research into biomechanics of obesity will rely heavily on anatomic models of the obese lower extremities, which until this work did not exist.

Keywords

Biomechanics, Computational Modeling, Obesity, Total Joint Arthroplasty

Pages

xiii, 82 pages

Bibliography

Includes bibliographical references (pages 75-82).

Copyright

Copyright © 2017 Kevin James Simoens

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