Structure and Function in Normal and Abnormal Hips: How to Rescue Mechanically Jeopardized Hips

212 Pages·1993·17.84 MB·English

by  Prof. Dr. Renato Bombelli (auth.)

Renata Bambelli
Structure
and Function
in Normal
and Abnormal
ps
H
-I
How to Rescue Mechanically
Jeopardized Hips
Third Edition, Revised and Enlarged
With 176 Figures in 578 Separate Illustrations
Springer-Verlag
Berlin Heidelberg New York
London Paris Tokyo
Hong Kong Barcelona
Budapest
RENATO BOMBELLI, Prof. Dr.
L. D. Clinica Ortopedica
Via Lampugnani 1
1-20025 Legnano
ISBN-13 :978-3-642-77979-4 e-ISBN-13 :978-3-642-77977-0
DOl: 10.1007/978-3-642-77977-0
Library of Congress Cataloging-in-Publication Data. Bombelli, Renato. Structure and function in
normal and abnormal hips:how to rescue mechanically jeopardized hips/Renato Bombelli. - 3rd
ed., rev. and en!. p. cm. Includes bibliographical references and index.
ISBN-13 : 978-3-642-77979-4
1. Hip joint-AbnormaUties. 2. Hip joint-Abnormalities-Surgery. 3. Hip joint-Mechanical properties.
4. Hip joint-Radiography. I. Title. RD772.B66 1993 617.3'76-dc20
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Preface
G.A. Borelli [19a, b] the Italian physiologist and physicist, though not a doctor,
was the first to study the position of the centre of gravity of the human body
and to explain muscular movement and other functions, according to the laws of
statics and dynamics in "De Motu Animalium" (1680-1681).
Subsequent contributors to this subject are so numerous [1, 3, 5, 6, 9, 27, 31,
39,42, 48, 60, 72, 74, 81, 84, 88, 89, 95-97, 104, 112, 114, 125, 137, 138, 146-148,
158,163,169,170,176,178,186,187,190,195,201,202, 204] that it is not possible
to cite them all, and, though they made many valuable contributions, not all their
conclusions are universally accepted.
The purpose of this book is to describe facts that can be deduced from the X-rays
of normal and mechanically abnormal hips and from the microscopic and macros
copic structural shape of the bone and cartilage. It appears that the biomechanical
stimuli are responsible for the shape, which in its turn, reduces the stresse's evoked
by load.
From these premises derive concepts which can be useful to orthopaedic surgeons
in their every-day practice. Concepts based on Pauwels' theory have been published
in previous books by the author [12, 16]. The present volume deals with some new
concepts and, findings, which are also supported by the invaluable contribution
of Professor Klaus Draenert and Doctor Yvette Draenert who provided their superb
histomorphologic pictures, which are deemed very valuable.
I would like to acknowledge the invaluable help I gained from the teachings
of Professor Friedrich Pauwels and dedicate my effort to the Great Master.
"We are dwarfs on giant's shoulders"
Particular thanks are due to Mr. Alan Graham Apley for his generous and unself
ish contribution of advice and for clothing my ideas in more elegant English.
Many thanks also to Professor Klaus Draenert and Doctor Yvette Draenert, for
the histological pictures that support some of the concepts described in the present
work, and to the Zentrum fUr Orthopadische Wissenschaften der Freien Universitat
Witten/Herdecke, Munich, Germany.
My gratitude to architect Marco Turri, an artist and a scientist, who has been
collaborating with me since 1974 in giving visual form to my ideas and to architect
Roberto Poretti for the mathematical calculations included in the present book.
I could not forget the support of the team of my colleagues, my excellent nurses
in' the Orthopaedic Department, and those responsible for administration in the
Busto Arsizio General Hospital, who have all been friendly and appreciative in
their work.
I am grateful to Dr. H. G6tze and the efficient and cordial staff of Springer-Verlag,
who, as in previous editions, have placed all the required facilities at my disposal
to make the book readable and pleasant to look at, many thanks.
RENAT O BOMBELLI
Contents
1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . 1
2 Biomechanical Interpretation of the X-rays of the Hip Joint:
Interpretation of Pelvic X-rays 3
2.1 X-rays of the Normal Pelvis 3
2.1.1 The Sourcil . . . 3
2.1.2 The Gothic Arch. . . . . 8
2.1.3 The Hourglass. . . . . . 9
2.2 How to Interpret the X-ray Appearances. 11
2.2.1 Fischer's Model: Phases of Gait and Path of the Centre of Gravity. 11
2.2.2 Pauwels' Model: Path of Centre of Gravity. . . . . . . . . .. 12
2.2.3 Previous Knowledge of Muscle Function. . . . . . . . . . .. 12
2.3 Interpretation of Muscular Activity According to the Gothic Arch . 21
2.3.1 Static Forces Acting on the Normal Hip: New Model 21
2.3.2 Dynamic Forces Acting on the Normal Hip 24
2.3.3 The A"normal Hip. . . . . . . . 24
2.3.3.1 Craniolateral Inclination of the WBS 24
2.3.3.2 Craniomedial Inclination of the WBS 32
2.3.3.3 Coxa Valga with a Horizontal WBS . 37
2.3.3.4 Coxa Valga with an Oblique WBS. 37
2.3.3.5 Coxa Vara with a Horizontal WBS . 37
2.3.3.6 Coxa Vara with an Oblique WBS . . 42
2.3.4 Consequences of Abnormal Hip Function 42
2.3.4.1 The Antalgic Gait . . . . . . . 42
2.3.4.2 The Duchenne or Short-Leg Gait. 43
2.3.4.3 The Trendelenburg Gait. 45
2.3.4.4 Friction. . . 45
2.3.5 Conclusions...... 55
3 Biomechanical Interpretation of Femoral X-rays . . . . . 57
3.1 Relationship Between the Physis and the Neck-Shaft Angle. 57
3,t.1 Coxa Valga ..... . 57
3.1.2 Coxa Vara. . . . . . . 57
3.1.3 Slipped Capital Epiphysis 67
3.1.3.1 Pathogenesis. 67
3.1.3.2 Treatment. 67
3.1.3.3 Statistics . . 79
VIII Contents
3.2 The Adult Femur. . . . . . . 88
3.2.1 Femoral Spherical Sector: Static 88
3.2.2 The Centre of Stress . . . . . 96
3.2.3 Femoral Spherical Sector: Dynamic . 102
3.2.4 Osteophytes. . . . . . . . 110
3.2.4.1 Positive Tension Osteophytes . 110
3.2.4.2 Negative Tension Osteophytes 110
4 Osteotomies. . . . . . . . 119
4.1 Pelvic Osteotomy. . . . . . 119
4.2 Intertrochanteric Osteotomy: Classification of OA 119
4.2.1 Valgus-Extension Osteotomy. . . . . . . 123
4.2.1.1 Aims of Valgus-Extension Osteotomy ... 123
4.2.1.2 How to Plan a Valgus-Extension Osteotomy 123
4.2.1.3 Operative Procedure . . . . . 135
4.2.1.4 Postoperative Care . . . . . . . . . . 143
4.2.1.5 Valgus Osteotomy in Medial OA .... 144
4.2.1.6 Effect of Valgus Osteotomy on the Knee. 144
4.2.2 Varus Osteotomy. . . . . . . . . 144
4.2.2.1 How to Calculate the Angle of Varus 157
4.2.2.2 Technique of Varus Osteotomy. . . 157
4.2.2.3 Postoperative Care . . . . . . . . 161
4.2.2.4 Effect of Varus Osteotomy on the Knee 161
4.2.2.5 Trochanteric Displacement. 162
4.3 The Role of Joint Cartilage 164
5 Bone Elasticity. ,. . . . . 169
5.1 How to Preserve Bone Elasticity in Total Hip Replacement 176
5.1.1 The Cup 180
5.1.2 The Stem 180
References. . 203
Subject Index" 209
1 Introduction
"Ich dachte traeumend
Ich traeumte denkend"
Franz Werfel
Human locomotion may be defined as alternate The base of the distal cone corresponds to the
ly pushing off with one foot while the other is "sourcil" described by Pauwels. The orientation
swinging forward. This simple definition hides of the sourcil determines that of the hourglass.
a number of factors, the nature of which has Only a horizontal sourcil is responsible for a
attracted many scientists in centuries past and vertical hourglass, which in turn is in the best
present. situation to buffer the vertical forces acting in
Technological advances and sophisticated the hip joint without producing shear stresses.
gadgetry in the present century have enabled It is interesting to note that the direction of
us to investigate joint mechanics, as well as the the bone lamellae of the Gothic arch also sug
human gait, in normal and in pathological con gests the direction of acting and reacting forces
ditions. Many of the conclusions arrived at are in the hip joint.
difficult to assess because they are based on dif Another concept described in the book, based
ferent models and expressed in mathematical on the particular feature of the bone structure
and engineering terminology not fully under visible on raster scanning electron microscopic
stood by orthopaedic surgeons who work in pictures, is the paramount importance to pre
such different fields. serve its elastic characteristics and not to jeopar
A simple method to investigate the function dize it, with rigid implants when a surgical treat
in the hip joint is to extrap~late from the shad ment is required. I would like to mention two
ows of its X-ray the forces at play. people in this regard: Gavrijl Abramovich Ili
In the pelvis a tridimensional structure made zarov and Robert Mathys. Ilizarov is a surgeon
of condensed bone lamellae buffers the shocks who made ample use of ingenuity to make up
produced in it by the femoral head with every the deficiency in facilities; Mathys is neither a
step and by the revolving head in the acetabu physician nor a surgeon, but rather an outstand
lum. It is clearly visible in axial and in antero ing mechanic with great experience in internal
posterior view X:rays; we call it hourglass. Its fixation implants. Both share the same concept
shape may be visualized as two opposite cones, and tend to achieve the same aim: one using
one cranial, one caudal, in contact with their a resilient external, the other a resilient internal
apexes. We call the distal cone a G.othic arch support in order to preserve the elasticity in
from its shape on anteroposterior view X-ray. bone.
2 Biomechanical Interpretation of X-rays of the Hip Joint:
Interpretation of Pelvic X-rays
Scientific method is based on models, but which 1. The sourcil (or eyebrow);
model should we choose when so many biologi 2. The Gothic arch; and
cal and biomechanical phenomena are still un 3. The hourglass.
known? In a living structure such as bone, the
The last two are located above the horizontal
distribution of inorganic and organic mass, the
sourcil, which is the term used to describe the
number and tension of the collagen fibres, the
radiographic appearance of the superior part of
precise value of the hydrostatic pressure and the
the facies semilunaris [15]; this sourcil is the
proportion of load transmitted outside and in
WBS (Fig. 1).
side the bone are not exactly known, so the
usual methods utilized in statics and dynamics
must be used with reservation. Since we do not
2.1.1 The Sourcil
fully understand the material, the values ob
tained by strain gauges are imprecise and can
Careful inspection of the anteroposterior (AP)
provide only a working hypothesis. So any hip
X-ray of a normal hip reveals, in the WBS of
model which the scientist's ingenuity visualizes
the acetabulum, a curved area of dense bone
can only be hypothetical.
which Pauwels [151] called the sourcil. The
There are four hip parameters to consider: shape of this dense area is semilunar; it develops
1. The orientation of the pelvic weight-bearing as a response to the stress imposed on the femo
surface (WBS) ral head by the counterthrust of the ground. In
2. The inclination of the abductor muscles (M) the normal hip, the uniform thickness and
3. The inclination of iliacus and psoas (I) smooth configuration of the sourcil are evidence
4. The anatomical sphericity of the head of the of the regular distribution ofthe stresses (Fig. 2);
femur its orientation is horizontal, not oblique [96, 97,
111, 154, 156] (Fig. 3).
We consider that. the best available model is
We can visualize the vertical upwardly di
an X-ray of the hip in which the location and
rected force in the femoral head as a vector P
direction of the lamellar pattern in the pelvis
acting against a concave acetabular area (Fig.
and in the upper portion of the femur indicate
4a-c). P can be resolved into a number of verti
the direction of forces acting on the jo'int. These
cally directed elements (dp); and as the acetabu
lamellae are the visual images of the forces act
lar surface is concave we can resolve each of
ing on the hip in static and dynamic phases
these elements into shear components Cry and
throughout life.
"ex) and a compressive component (0"). At the
pole or centre of the weight-bearing acetabular
area there are only 0" vertical compressive forces,
at the equator of the hemispherical surface only
shear forces ("e and "ex). Between the pole and
2.1 X-rays of the Normal Pelvis y
equator, the vertical forces may be resolved into
the compressive (0") and shear components ("e
y
In the X-ray of the normal hip three landmarks and "ex). While the magnitude ofthe compressive
can be seen in the pelvis: components diminishes from the centre towards
4 Biomechanical Interpretation of X-rays of the Hip Joint: Interpretation of Pelvic X-rays
W.B.S.
Fig. 1. Anteroposterior X-ray of a normal hip. The sour
cil is horizontal (CR, centre of rotation; WBS, weight
bearing surface)
Fig. 2. X-ray of a normal hip. The oblique force R (white
arrow), directed to the centre of rotation (CR), passes
through the inner third of weight-bearing surface (WBS);
the vertical force P (black arrow) through its centre. The
R
structure of the sourcil (eburnation of the upper acetabu
lar surface) is the result of strain in the bone and reflects
the stresses put upon it. The uniformity of eburnation
indicates that only the vertical compressive force passing
perpendicularly through the centre of the eburnated area
and through CR produces evenly distributed stresses
Fig. 3. According to Pauwels, the weight-bearing surface
must be oblique in order for the oblique resultant force
R to cross its centre perpendicularly
The Sourcil 5
b
a
Fig. 4. a The force ~, counter-resultant of compressive 5 T~e:SS OF d
force P, is the resultant of component forces dp• Each
of these may be resolved into perpendicular cr and tan
'x 'yo
gential components and b The component forces
of ~ on a concave surface (sourcil) act with compressive
and shear forces. At the centre of the weight-bearing
'x
surface cr is at maximum, and 'yare zero. At the
'x
equator cr is zero and and 'yare at maximum. c Dia
gram of compressive and tangential stresses
C~
ST~ESS OF ty
c
C~