Imaging and Treatment of Chronic Midportion Achilles - RePub

196 Pages·2010·2.34 MB·English

Imaging and Treatment of Chronic
Midportion Achilles Tendinopathy
Robert-Jan de Vos
ISBN: 978-90-8559-053-8
Cover by: Robert-Jan de Vos, Evelien Kerkhof and Remko Verhagen
Layout and printing: Optima Grafische Communicatie, Rotterdam, the Netherlands
© R.J. de Vos, the Netherlands, 2010. All rights reserved. No part of this thesis may be
reproduced or transmitted in any form or by any means, without prior written permis-
sion by the author
Imaging and Treatment of Chronic Midportion
Achilles Tendinopathy
Beeldvorming en behandeling van chronische midportion
Achilles tendinopathie
Proefschrift
ter verkrijging van de graad van doctor aan de
Erasmus Universiteit Rotterdam
op gezag van de
rector magnificus
Prof.dr. H.G. Schmidt
en volgens het besluit van het College voor Promoties
De openbare verdediging zal plaatsvinden op
woensdag 22 September 2010 om 15.30 uur
Door
Robert Johannes de Vos
Geboren te Gouda
PRoMoTIeCoMMIssIe
Promotoren
Prof.dr.ir. H. Weinans
Prof.dr. J.A.N. Verhaar
overige leden
Prof.dr. B.W. Koes
Prof.dr. R.L. Diercks
Prof.dr. C.N. van Dijk
Copromotoren
dr. J.L. Tol
dr. H.T.M. van Schie
Contents
Chapter 1 General Introduction 7
Chapter 2 Interobserver reliability of neovascularisation score using Power 23
Doppler ultrasonography in midportion Achilles tendinopathy
Chapter 3 The value of Power Doppler ultrasonography in Achilles 35
tendinopathy – a prospective study
Chapter 4 Ultrasonographic Tissue Characterisation of human Achilles 49
tendons: quantification of tendon structure through a novel
non-invasive approach
Chapter 5 Tendon structure is not related to clinical outcome following 63
eccentric exercises in chronic midportion Achilles tendinopathy
Chapter 6 Effects of platelet-rich plasma on ultrasonographic findings in 79
chronic midportion Achilles tendinopathy
Chapter 7 The additional value of a night splint to eccentric exercises 95
in chronic midportion Achilles tendinopathy – a randomised
controlled trial
Chapter 8 Autologous growth factor injections in chronic tendinopathy – 111
a systematic review
Chapter 9 Platelet-rich plasma injection for chronic Achilles tendinopathy – 129
a randomised controlled trial
Chapter 10 General Discussion 145
Chapter 11 Summary 161
Appendices Nederlandse samenvatting 171
Dankwoord 179
Curriculum Vitae 183
PhD Portfolio Summary 185
List of publications 189
VISA-A questionnaire 193

Chapter 1
General Introduction

General Introduction 9
PRefACe
According to the Greek mythology Achilles, the legendary warrior from Iliad, was in-
vulnerable except for his heel. Since he died due to an arrow that pierced his Achilles
tendon, the “Achilles’ heel” symbolises a person’s principal weakness. Nowadays, weak-
ness of the Achilles tendon is increasingly gaining attention to medical specialists.
Achilles tendon disorders are a common entity in middle-aged active people, but
can also affect the sedentary individuals.1-3 With increasing sports participation in the
general population, the number of overuse injuries has increased.1 Tendon disorders
comprise 30-50% of all sports-related injuries 3 and there is a lifetime risk of 52% in elite
long-distance runners of suffering from an Achilles tendon injury.4 Despite the high
prevalence there is still a lack of knowledge about the aetiology and pathogenesis of
these injuries.
The terminology used to describe chronic tendon disorders has changed in the past
few decades.5 For many years this condition was persistently defined as “tendinitis”, de-
noting an inflammation of the tendon. Several authors proposed abandoning this term,
as there were no signs of inflammation in chronic painful tendons analysed after biopsy
or with microdialysis.5-8 To redress this confusing terminology, the term “tendinopathy”
was introduced to describe the clinical condition. Histopathological studies showed
that tendinopathy is frequently characterised by degeneration of the tendon tissue, also
referred to as “tendinosis”.7 The term tendinosis is based on histopathological character-
istics and should only be used after histopathological confirmation.3 The treatment of
tendinopathy has been challenging in sports medicine and orthopaedics and therefore
it is becoming a major problem in this field. Below an overview will be given on several
aspects of chronic Achilles tendon disorders, with a special focus on the imaging and
treatment modalities.
AnAToMy of The AChIlles Tendon
The Achilles tendon is the strongest and largest tendon in the human body, which con-
nects the calf muscles with the calcaneal bone.9 The midportion of the tendon shows
a spiral rotation around its axis that works as an elastic coil functioning as an energy-
storing tendon to improve the efficiency of locomotion.9,10 During running the Achilles
tendon is subjected to tensile loads up to twelve times the body weight.11 These forces
are transmitted through the tendon collagen bundles, which are hierarchically arranged
and well ordered predominantly in a longitudinal direction (Figure 1.1).12 The densely
packed collagen, mainly type I fibres, gives the tendon its typical white glistening ap-
pearance.13 Tendon collagen is the main extracellular matrix (ECM) component and it is
10 Chapter 1
figure 1.1 – The hierarchical structure of a tendon. Collagen forms microfibrils, fibrils, and fibres. A
group of fibres constitutes a fascicle. The fascicles unite to form bundles, and are surrounded by the
endotenon. The endotenon is a mesh of connective tissue that holds the bundles together and allows
some movement of the bundles relative to each other. It carries the longitudinally running blood vessels
and nerves. A fine connective tissue sheath, the epitenon, is continuous throughout its inner surface with
the endotenon and surrounds the whole tendon. The paratenon is a thin membrane surrounding the
epitenon and functions as an elastic sleeve permitting free movement of the tendon against adjacent
structures. The peritendon is a general descriptor that consists of the epitenon and the paratenon
(modified from Kirkendall & Garret, 1997).
produced by sparsely distributed tenocytes.2,7 The tenocytes, or specialised fibroblasts,
normally have a flat phenotype. The major non-collagenous ECM constituents are water
and proteoglycans which are core proteins that link the glycosaminoglycans (GAGs)
to one large glycosaminoglycan chain.14 The GAGs contain large amounts of bonded
negatively charged sulphate ions and thereby extract also free positive charged ions
(sodium) from the environment. The subsequent resulting high concentrations of ions
attract water in order to balance the internal and external ion concentrations.15 As long
as the collagen fibres are well-organised and intact, the matrix does not expand due to
the water attraction. The collagen fibres are exposed to an internal stress that balances
the water impression. The collagen fibres in the ECM of healthy tendons are in a state
of dynamic equilibrium between synthesis and degradation regulated by matrix metal-
loproteinases and their inhibitors.7,16
Small blood vessels run throughout the Achilles tendon in the longitudinal plane. The
blood supply of the Achilles tendon is physiologically the lowest in the midportion, 2-7 cm
proximal from the insertion of the tendon on the calcaneal bone.13,14 This area is therefore
defined as the “watershed region”, although this limited blood supply should be sufficient
for the metabolic needs of the tendon.17 The longitudinally arranged blood vessels are
accompanied by nerves and it is known that the body of the tendon is poorly innervated.