ENGINEERING TRANSACTIONS
ROZPRAWY INŻYNIERSKIE
A QUARTERLY JOURNAL
- S.C. Cowin:
Adaptive Elasticity: A Review and Critique of a Bone Tissue Adaptation Model
- P. Kowalczyk:
Influence Of Bone Anisotropy On Stress Distribution
And Optimum Shape Of Cementless Femoral Implants
- A. John, P. Orantek:
Computer Aided Modelling of Human Pelvic Bone
- M. Gzik, D. Tejszerska:
Dynamical Forces Inside Facet Joints, Intervertebral Discs and
Ligaments of Human Cervical Spine
- D. Jasińska--Choromańska, J. Deszczyński:
A New Type of External Fixation
- D. Jasińska-Choromańska, I. Sadzyński:
Monitoring Techniques of Bone Fracture Healing Using External
Fixators
- M. Stańczyk, J. J. Telega:
Heat Transfer Problems in Orthopaedics
- J. Chłopek, G. Kmita:
Non-Metallic Composite Materials for Bone Surgery
- K. Skiba:
Diagnostics and Treatment of Traumatic Damages to Achilles Tendon
- E. Wiczkowski, A. Kędzia, A. Kania:
Raumatic Damage Pathomechanism of Cerebral Vessels Caused by
Geriatric Changes
- S.C. Cowin:
Adaptive Elasticity: A Review and Critique of a Bone Tissue Adaptation Model
- Living bone is continually undergoing processes of
growth, reinforcement and resorption. These processes are termed
collectively ``remodeling''. The remodeling processes in living
bone are the mechanisms by which the bone adapts its histological
structure to changes in long-term loading. The theory of adaptive
elasticity was developed as a model for the mechanical load
induced adaptation of bone. All three aspects of the theory of
adaptive elasticity are reviewed here. These include internal
adaptation, surface adaptation and architectural adaptation. The
successes of the theory as well as the features of the theory that
should now be revised are discussed.
Contents
- P. Kowalczyk:
Influence Of Bone Anisotropy On Stress Distribution
And Optimum Shape Of Cementless Femoral Implants
- Implant separation from bone tissue, resulting in the necessity
for revision surgery, is a serious drawback of cementless total
joint replacement. Unnatural stress distribution around the
implant is considered the main reason for the failure.
Optimization of the implant properties, especially its geometric
parameters, is believed to be the right way to improve reliability
of joint prosthetics. Numerical models of femur--implant system
enabling approximate analysis of stress distribution and shape
optimization of implants suffer from numerous simplifications as,
e.g., the assumption of bone isotropy, which may put in question
reliability of the results obtained. In this paper, a numerical
model including orthotropic properties of both cancellous and
cortical bone is presented and influence of this assumption on
results of the analysis and optimization is investigated.
Contents
- A. John, P. Orantek:
Computer Aided Modelling of Human Pelvic Bone
- Numerical modelling of human pelvic bone makes it possible to
determine the stress and strain distribution in bone tissue.
Before numerical analysis, the geometrical model of analyzed
structure should be prepared. It is an important step in numerical
analysis because the obtained results depend on it. Up to the
present, in the most of examples, the creation of geometrical
model was done in a simple but time-consuming way. In the paper
the numerical routine, translating data from the coordinate
measuring machine to the Patran code is presented. At the first
step, the geometrical model with the layer structure of bone
tissue is created. The geometrical data is the basis to create an
FE mesh. After meshing, the boundary conditions and load should be
assumed. When the load and boundary conditions are known, the
strain and stress distribution can be calculated using the Nastran
or Advanced FEA code. The presented program enables to reduce the
time of creation of numerical model.
Contents
- M. Gzik, D. Tejszerska:
Dynamical Forces Inside Facet Joints, Intervertebral Discs and
Ligaments of Human Cervical Spine
- The paper presents a dynamic spatial mathematical model in which a
head, seven cervical vertebrae, a group of 19 couples of neck
muscles, 6 intervertebral discs, ligaments and facet joints are
taken into consideration. The created model enables simulation of
dynamical forces inside anatomical parts of human neck. The
behaviour of the modelled body exposed to action of a~force
corresponding to the real enforcement, which occurs at a head-on
collision during the road accident was simulated, and the model
was verified on the basis of the data obtained from published
experiments.
Contents
- D. Jasińska--Choromańska, J. Deszczyński:
A New Type of External Fixation
- The paper presents some problems related to external
osteosynthesis. Design of the new generation of external fixators
should use modelling, computer simulation and clinical
postulates. New generation of external fixators has been equipped
with the measuring system of the bone healing process. Some of the
important problems connected with the mechatronical and clinical
aspects of the external fixator design and clinical application
are presented.
Contents
- D. Jasińska-Choromańska, I. Sadzyński:
Monitoring Techniques of Bone Fracture Healing Using External
Fixators
- Long bone fractures can be healed using external fixators -
devices that stiffly fix the fractured fragments, attached to the
bone by pins parallel to the bone frame. This method enables to
benefit both from healing and diagnostics of fracture during
osteogenesis. Osteogenesis, traditionally diagnosed using X-rays
methods (RTG, densitometry), can also be more precisely determined
with mechanical properties like strength and stiffness inside the
fracture slot. The treatment of long bone fractures by external
fixators offers a unique opportunity to control the healing of the
fracture by measuring the compression forces on the frame, that
occurs under the load applied to the bone and depends on the
mechanical properties of the fracture. The procedure of
measurement of the compression force on the frame can be performed
using tensometers, what is a cheap and simple method, and can be
performed by the patient at home. The measurement of osteogenesis
gives a possibility of more precise diagnostics of the fracture.
It can also be combined with computer techniques like artificial
intelligence. The paper presents one of the methods of monitoring
the bone fracture healing.
Contents
- M. Stańczyk, J. J. Telega:
Heat Transfer Problems in Orthopaedics
- The present paper presents a comprehensive review of the heat
transfer problems in orthopaedics. The emphasis is put on
presenting clinically relevant issues along with the purpose and
motivation for studying the presented problems. The available
experimental methods and results are presented and the modelling
approaches are described -- mathematical formulations and
numerical results.
The first of the problems studied is the bone cement heating
during cemented implantations, special attention being paid to
modelling the kinetics of the acrylic bone cement polymerisation.
Next, the heat production during drilling and sawing of the bone
is discussed. Eventually, the results concerning frictional
heating of the articulating joints are presented.
Contents
- J. Chłopek, G. Kmita:
Non-Metallic Composite Materials for Bone Surgery
- Possibility of using non-metallic materials in biomedical
applications was considered. The attention was focused mainly on
polymer materials and both the carbon-carbon and carbon-reinforced
polymer composites, their mechanical and biological properties.
The obtained results indicate that some of these materials can be
successfully used instead of metallic implants for biomechanical
functions.
Contents
- K. Skiba:
Diagnostics and Treatment of Traumatic Damages to Achilles Tendon
- Traumatic damages of Achilles tendon constitute an important and
serious problem in clinical practice. Many theories are applied in
order to explain the pathomechanism of traumatic damages of
Achilles tendon. Among them, there is a mechanical theory which
claims that sudden and not co-ordinated contraction of the calf
triceps muscle with plantarly bent foot and extended limb causes
rupture of the tendon continuity. In clinical practice, Achilles
tendon appeared more susceptible to rupture in persons over 35
when elasticity degree is reduced due to the tendon deformative
lesions (fragmentation and collagen fibres homogenisation).
In the Department of Traumatic Surgery and Hand Surgery of the
Wroc{\l}aw University of Medicine, since 1993, clinical surveys
have been carried on upgrading the surgical treatment methods of
traumatic and subcutaneous ruptures of the Achilles tendon. In
years 1995--1999, the examinations were carried on in co-operation
with the Institute of Material Science and Applied Mechanics,
Wroc{\l}aw University of Technology in order to explain the
pathomechanism of traumatic lesions of Achilles tendon. New
examination methods such as: ultrasonography, tomography, magnetic
resonance as well as recent thermovision method contribute largely
towards evaluation of both early and long-term results of
operative treatment.
Contents
- E. Wiczkowski, A. Kędzia, A. Kania:
Raumatic Damage Pathomechanism of Cerebral Vessels Caused by
Geriatric Changes
- The knowledge of mechanical properties of the brain blood vessels
enables an assessment of pathological changes caused by human
aging. As it results from our investigations, a greater elasticity
of blood vessels in the occipital region accounts for the rare
occurrence of subdural space blood clots in this region of the
brain. Also, a map can be derived based on our results, of the
most severe head trauma directions causing damages of blood
vessels in the subdural space.
Contents
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