The mechanobiology of diaphyseal secondary bone healing [Elektronische Ressource] / vorgelegt von Devakara Rao Epari

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• Publié par: technische_universitat_berlin
• Publié le: 01 janvier 2006
• Nombre de lectures: 13
• Langue: English
• Poids de l'ouvrage: 4 Mo

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THE MECHANOBIOLOGY OF DIAPHYSEAL SECONDARY
BONE HEALING







vorgelegt von
Devakara Rao Epari B.E., M.Biomed.E
aus Australien




Von der Fakultät V – Verkehrs- und Maschinensysteme
der Technischen Universität Berlin
zur Erlangung des akademischen Grades

Doktor der Ingenieurwissenschaften
– Dr.-Ing. –




genehmigte Dissertation





Promotionsausschuss:
Vorsitzender: Prof. Dr. med. Wolfgang Friesdorf
Berichter: Prof. Dr.-Ing. Georg N. Duda
Berichter: Prof. Dr.-Ing. Marc Kraft





Tag der wissenschaftlichen Aussprache: 28. März 2006



Berlin 2006
D83
iTo my beloved and devoted parents, Margaret and Sankararao
















"Live as if you were to die tomorrow. Learn as if you were to live forever."
Mohandas K. Gandhi (1869 - 1948)
ii
Preface
The present thesis arose from my activities as a research assistant at the
Musculoskeletal Research Centre Berlin – Centre for Musculoskeletal Surgery
(Director: Prof. Dr. med. N. P. Haas), Charité - Universitätsmedizin Berlin, which is a
joint institution of the Free University and the Humboldt-University of Berlin.
This work would not have been possible without the support and vision of Prof. Dr.
Ing. Georg N. Duda. His advice has been invaluable to me and his perpetual drive for
perfection has encouraged me to continually set higher standards for myself which has
added considerably to the quality of this thesis.
I would like thank Prof. Dr. Ing. Marc Kraft for reviewing and supporting my thesis,
his comments were most helpful in focusing the work.
My thanks must also go to my first mentor, A/Prof. William Walsh, for passing on his
enthusiasm for orthopaedic research and for giving me my first research opportunities
in his laboratory in Sydney, Australia.
I gratefully acknowledge the contributions of our lab veterinarian Dr. Hanna Schell
who was responsible for surgery and care of the animals. In addition, our discussions
on the biology of healing were most stimulating. Also, my thanks go to Dr. Jean-
Pierre Kassi and Mr Jan-Eric Hoffmann for their work in developing and testing the
external fixation devices. I am grateful to my engineering colleagues Dr. Markus
Heller and Dr. Mark Thompson for providing critical review and constructive
discussion. I would also like to thank my fellow lab colleagues who have contributed
to creating a pleasant and friendly working atmosphere.
Thanks must go to the AO Foundation (Switzerland) for their financial support.
To my close friend and colleague Dr. William Taylor, I am particularly grateful for all
his assistance, since the day I arrived in Berlin. His mateship has made an at times
daunting relocation overseas so much easier.
Finally, words can not express my gratitude to my parents. For their hard work and
sacrifice that has given me this opportunity I am deeply indebted. They believed in
and encouraged me always and have in no small way contributed to who I am today.
In spite of the huge distance separating us, my family remains very close to my heart.
iiiTable of Contents

















Preface..........................................................................................................................iii
Table of Contents ........................................................................................................iv
Summary....................................................................................................................viii
Zusammenfassung........................................................................................................x
1 Introduction..........................................................................................................1
1.1 Background....................................................................................................2
1.2 Problem3
1.3 Goals..............................................................................................................3
1.4 Hypothesis......................................................................................................3
1.5 Outline of Thesis............................................................................................4
2 Healing of Diaphyseal Fractures ........................................................................7
2.1 Basic Anatomy of Diaphyseal Bone ..............................................................8
2.2 Fracture Healing.............................................................................................9
2.2.1 General...................................................................................................9
2.2.2 Secondary Bone Healing......................................................................10
2.3 Fracture Treatments.....................................................................................13
2.3.1 Splinting...............................................................................................13
2.3.2 Interfragmentary Compression............................................................14
2.4 Complications in Fracture Healing ..............................................................15
2.5 Mechanics and Bone Healing15
2.5.1 Influence of Mechanics on Bone Healing............................................15
2.5.2 Mechano-biology of Bone Healing......................................................18
iv
3 Morphology of Bone Healing ............................................................................25
3.1 Introduction..................................................................................................26
3.2 Materials and Methods.................................................................................28
3.2.1 External Fixators..................................................................................28
3.2.2 Animals................................................................................................30
3.2.3 Surgical Procedure...............................................................................30
3.2.4 Radiological and Clinical Observations...............................................31
3.2.5 In vivo Monitoring of Fixation Stability..............................................31
3.2.6 Biomechanical Testing – Torsional Moment and Stiffness.................32
3.2.7 Moment of Inertia................................................................................33
3.2.8 Histologic and Histomorphometric Analysis.......................................34
3.2.9 Statistical Analyses..............................................................................34
3.3 Results..........................................................................................................35
3.3.1 Radiological and Clinical Results........................................................35
3.3.2 Mechanical Testing of Explanted Tibia...............................................35
3.3.3 Moment of Inertia37
3.3.4 Qualitative Histology...........................................................................38
3.3.5 Quantitative Histomorphometry..........................................................42
3.4 Discussion....................................................................................................45
3.5 Conclusion...................................................................................................49
4 Mechanical Conditions during Bone Healing..................................................51
4.1 Introduction..................................................................................................52
4.2 Methods........................................................................................................55
4.2.1 Influence of Interfragmentary Movement............................................55
4.2.2 Influence of Hard Callus Maturation ...................................................57
4.3 Results..........................................................................................................61
4.3.1 Influence of Interfragmentary Movement61
4.3.2 Influence of Hard Callus Maturation67
4.3.3 Analysis of In Vivo Experimental Conditions.....................................69
4.4 Discussion....................................................................................................71
4.4.1 Influence of Interfragmentary Movements ..........................................71
4.4.2 Influence of Hard Callus Maturation ...................................................75
4.5 Conclusion...................................................................................................79


v5 Mechano-biology of Bone Healing....................................................................81
5.1 Summary of Findings...................................................................................82
5.2 Consequences for Mechano-biology............................................................83