ENGINEERING TRANSACTIONS
ROZPRAWY INŻYNIERSKIE
A QUARTERLY JOURNAL
The issue is devoted to
Modelling in Biomechanics
Guest editor: Prof. Józef Joachim Telega
- P.J. Prendergast:
An analysis of theories in biomechanics
- S. Tokarzewski, J.J. Telega and A. Gałka:
Torsional rigidities of cancellous bone filled with marrow:
the application of multipoint Padé approximants
- T. Lekszycki:
On a class of bone cell-based remodeling laws with spatial fading influence of stimuli
- J. Litniewski, A. Nowicki and A. Sawicki:
Bones characterisation with ultrasound
- J. Kubik, M. Kaczmarek and M. Pakula:
On observation of slow ultrasonic waves in cancellous bones
- L. Skubiszak and L. Kowalczyk:
Relation between the mechanical properties of muscles and their structure
on the molecular level
- S. Jemioło and J.J. Telega:
Modelling elastic behaviour of soft tissues. Part I. Isotropy
- S. Jemioło and J.J. Telega:
Modelling elastic behaviour of soft tissues. Part II. Transverse isotropy
- A. Gałka, J.J. Telega and R. Wojnar:
Modelling electric and elastic properties of cartilage
- E. Szwajczak, A. Kucaba-Piętal and J.J. Telega:
Liquid crystalline properties of synovial fluid
- A. Ślósarczyk:
Significance of bioceramics for bone surgery
- S. Piszczatowski and K. Skalski:
Visco-elastic analysis of the femur-implant system by using finite element approach
- D. Jasińska-Choromańska:
Computer modelling and simulation techniques as a tool for aiding the design
of orthopaedic unilateral external fixators - focused on innovative solutions
- J. Bauer and M. Pyrz:
Evolutionary programs in the optimization of cementless hip prosthesis
- T. Kotwicki and W. Marciniak:
Optimal three-dimensional correction of idiopathic scoliosis
- P.J. Prendergast:
An analysis of theories in biomechanics
- The nature of the systems commonly thought of as coming into the remit of biomechanics
range from 'mechanical' systems (concerned with the design of medical devices, such as
implants) to 'mechanobiological' systems (concerned with the response of tissues, cells,
and biomolecules to mechanical forces). In each case, a biomechanical system is
characterised by the interaction of biological and physical elements. Like any other
science, biomechanics advances by the development of theories and the testing of these
theories by observation and experiment. The purpose of this paper is to analyse
contemporary biomechanics research by providing a critique of the development of
biomechanical theories. Only two are considered in detail: (i) the theory of hip
prosthesis failure and (ii) the theory of adaptive-bone remodelling. In both cases,
specific basic statements, or hypotheses, have been proposed and tested using
computational and experimental methods. In the case of hip implants, there have been
definite advances in the sense that many hypotheses that could have been rejected
continue to be upheld despite severe testing. On the other hand, in the case of
adaptive-bone remodelling where the dominant theory is 'adaptive elasticity', the tests
of the theory have either been too lenient or they have smuggled in new assumptions that
fundamentally alter it. The problems of testing adaptive-elasticity theory are described,
and comparison is made with damage-based bone remodelling theories.
Contents
- S. Tokarzewski, J.J. Telega and A. Gałka:
Torsional rigidities of cancellous bone filled with marrow:
the application of multipoint Padé approximants
- An idealized model of prism-like trabecular bone was developed to study its static and
dynamic responses under torsional moments. Effects of bone marrow and bone apparent
density were investigated. By constructing multipoint Padé approximants [1-2]
to the torsional complex modulus, hydraulic stiffening of the prism-like bone due to the
presence of bone marrow was predicted. The torsional compliance, creep function and
relaxation function were also evaluated.
Contents
- T. Lekszycki:
On a class of bone cell-based remodeling laws with spatial fading influence of stimuli
- In the present paper the elms of cell-based bone remodeling laws is considered. The
fundamental assumption is that of fading in space influence on actor cells osteocytes
functioning as sensors. The actor cells - osteoblasts and osteoclasts are responsible for
the changes of bone micro-structure. The model proposed in the previous publications of
other authors, is based on the resumption of exponential influence function and density
of strain energy as the stimulus to which the osteocytes are sensitive, see [11, 12, 14].
As the result of the adaptation according to such remodeling law the porous material is
created. The topology of the micro-structure of this material is dependent on the
mechanical loading conditions and the characteristics of the interactions of cells. The
aim of the present work was to examine if this phenomenon is characteristic only for this
specific law or represents a rather general property associated with the hypothesis of
fading influence of the cells. Different influence functions were examined for different
functionals selected to represent the stimulus. It follows from the these considerations
that the fading influence of the cells plays fundamental role for the remodeling process
and the creation of trabecular structure. Such structures were obtained for several
adaptation laws based on different influence functions and functionals representing the
stimulus. They were compared with the results obtained for the adaptation law proposed
and discussed in [11, 12, 14]. The numerical calculations suggest that the idea of
spatial fading influence of the cells can be possibly combined in future with the results
of the research on the biological mechanisms of the bone remodeling to propose more
sophisticated models.
Contents
- J. Litniewski, A. Nowicki and A. Sawicki:
Bones characterisation with ultrasound
- Macroscopic, X-ray methods for bone quality assessment are mainly based on porous bone
density measurements. The bone quality is a property that is difficult to define, as it
is related to both density and structure of the bone. In recent years, several new
ultrasonic diagnostic methods have been developed to examine bones "in vivo". These
methods are based on measurements of the velocity (SOS - speed of sound) and attenuation
(BUA - broadband ultrasound attenuation) of waves penetrating porous bones. The large
interest in these methods is a result of the fact that they provide information not only
about the bone density but also about their structure without using ionizing energy. The
principal element that determines the bone strength is the trabecular structure of a
porous bone. In our project we measure acoustic properties of a single trabecula using a
scanning acoustic microscope and we introduce the system for "in vivo" measurement of an
overall properties of a calcaneus (a heel bone).
Contents
- J. Kubik, M. Kaczmarek and M. Pakula:
On observation of slow ultrasonic waves in cancellous bones
- The two-phase model of saturated cancellous bones predicts the existence of two
longitudinal waves in the materials. The paper discusses experimental results concerning
ultrasonic studies of the slow longitudinal wave. Results available in the literature axe
reviewed and compared with author's data obtained through broadband ultrasonic
spectroscopy. The essential properties of the measured slow wave as well as technical and
material difficulties in interpretation of the data are highlighted.
Contents
- L. Skubiszak and L. Kowalczyk:
Relation between the mechanical properties of muscles and their structure
on the molecular level
- Mechanical properties of the vertebrate skeletal muscles are satisfactorily described on
the basis of a new model of the myosin molecule packing into the thick filament.
Contents
- S. Jemioło and J.J. Telega:
Modelling elastic behaviour of soft tissues. Part I. Isotropy
- Soft tissues mostly exhibit strongly nonlinear behaviour while undergoing large strains.
New macroscopic models for both isotropic and transversely isotropic soft tissues have
been proposed. The models developed are suitable for finite element formulation. It the
first part of the paper isotropic models have been proposed. Implementation in the FEM
programme ABAQUS has been discussed. Muscle contraction models have also been concisely
reviewed.
Contents
- S. Jemioło and J.J. Telega:
Modelling elastic behaviour of soft tissues. Part II. Transverse isotropy
- New constitutive relationships for hyperelastic transversely isotropic materials have
been proposed. The well-known isotropic hyperelastic model due to Ogden [I.58] has been
extended to transverse isotropy. It has been shown that some models intended to describe
the nonlinear elastic behaviour of soft tissues are oversimplified and lead to incorrect
results. An overview of soft tissue modelling, being a continuation of the one started
in [48], has also been given.
Contents
- A. Gałka, J.J. Telega and R. Wojnar:
Modelling electric and elastic properties of cartilage
- The aim of the paper is to propose a novel approach to modelling the macroscopic
electromechanical behaviour of cartilage within the framework of linear response. The
cartilage is treated as multiphase material with four constituents: anions, cations,
viscous fluid and piezoelectric skeleton. The macroscopic equations were derived by using
homogenization methods. Only stationary flow was studied. The elastic macroscopic moduli
were determined by assuming, after Broom [60], the honeycomb microstructure of the
cartilage. Mathematical developments are preceded by a review of structure and properties
of a cartilage.
Contents
- E. Szwajczak, A. Kucaba-Piętal and J.J. Telega:
Liquid crystalline properties of synovial fluid
- The main aim of this paper is to discuss the liquid crystalline concept of synovial
fluid. This new concept was proposed by Kupchinov [30] and was next developed
in [31, 32, 58]. According to these papers, the crystalline structure of synovia
ensures very low friction coefficient in human (and animal) joints. Experimental data
in favour of crystalline structure of synovia have been discussed. Mathematical model
of such fluid, based on Eringen's theory [14, 15], has been advanced.
Contents
- A. Ślósarczyk:
Significance of bioceramics for bone surgery
- The paper presents ceramic implant materials used in orthopaedics, restorative dentistry,
maxillofacial surgery and otholaryngology. In addition to oxide ceramics, also materials
on the basis of calcium phosphates are presented, including composites with
hydroxiapatite or TCP matrix. Possible types of behaviour of implantation materials and
living tissues as well as resulting classifigaltion of biomaterials, subdivided into:
nearly inert, bioactive and resorbable, are discussed. Attention was drawn to the most
prospective directions of research studies of biomaterials for the future.
Contents
- S. Piszczatowski and K. Skalski:
Visco-elastic analysis of the femur-implant system by using finite element approach
- The subject of this work is to elucidate the significance of rheological processes taking
place in a bone-implant system when the implanted joint is bearing a load. The processes
of mathematical modelling (by variational formulation and finite element approach) and
computer - aided strength analysis of a human hip joint endoprosthesis-femoral bone
system, taking into account the rheological properties of bone tissue, are presented. The
three distinct types of material that are present in the system (cortical bone,
trabecular bone and implant) exhibit significant differences in their elastic and
rheological properties. The analysis is carried out using the finite element method.
Consideration of the rheological properties of bone tissue during the analysis makes it
possible to observe, under conditions of fixed loads, the changes in the fields of
stresses, strains and strain energy density in the bone - implant system.
Contents
- D. Jasińska-Choromańska:
Computer modelling and simulation techniques as a tool for aiding the design
of orthopaedic unilateral external fixators - focused on innovative solutions
- The paper presents the methods of modelling and simulation of the bone-external fixator
system for fracture healing of long bones. Special emphasis was put on relations between
clinical assumptions and the applied analytical and simulation apparatus. Concepts of
application of heuristic techniques based on artificial neural networks for studying the
process of bone union are presented. Together with the results of the simulation studies,
some results of the examinations performed under clinical conditions are presented.
Contents
- J. Bauer and M. Pyrz:
Evolutionary programs in the optimization of cementless hip prosthesis
- The optimal design of cementless hip prosthesis is investigated in the paper. Design
variables are materials (represented by their Young's moduli) of the non-homogenous stem
prosthesis, disposed in vertical layers. The minimisation of the interface stress
function with constraints on the resorbed bone mass reaction is presented. A simplified
two-dimensional FEM model of a stem-bone configuration is considered, enabling however to
obtain essential characteristics of the stem-bone load-transfer mechanism. Evolutionary
algorithm approach is applied to find the optimal solution.
Contents
- T. Kotwicki and W. Marciniak:
Optimal three-dimensional correction of idiopathic scoliosis
- We have reviewed the standing position antero-posterior and lateral radiographs of 64
children operated on for juvenile or adolescent idiopathic scoliosis. Twenty five
patients had Cotrel-Dubousset posterior instrumentation, twenty one were corrected with
Pouliquen anterior plate and twenty one with Harrington distraction rod. The transversal
plane of the spine was visualised by computer reconstruction using sonic digitizer GP-9
and the programme Rachis. The following parameters were compared: Cobb angle, Perdriolle
angle of vertebral rotation, apical vertebra transposition. Transversal plane
reconstruction images were also compared. The results showed better 3-D correction in
Cotrel-Dubousset technique over the Harrington technique. This concerned Cobb angle and
apical vertebra transposition but not the vertebral rotation. The anterior
instrumentation gave the best correction in each of the three planes. In particular, the
vertebral rotation was significantly diminished with anterior technique. The results were
also confirmed by computer reconstruction of the transversal plane of the spine. The
authors conclude that vertebral derotation can hardly be achieved with posterior spinal
techniques, regardless of the type of instrumentation applied. Following the
biomechanical analysis of the spatial displacement of each vertebra of the scoliotic
curve after operation, a complex movement of the.corrected spine can be evaluated.
Contents
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