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1

Biomechanics of Bone-Fracture Fixation by External Unilateral Mechatronic Ortopaedic Fixators

Choromański W., Leśniewska A.

Machine Dynamics Research

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2010

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Vol. 34, No. 2

78-86

EN

In the external fixation of fractured bone by means of bone-external fixation device fastened to the bone, an on-going concern has been determined the stress distribution at fracture as well as at fixation sides during the whole fracture healing process. In order to address this problem, it has been proposed to use Uunilateral Mechatronic Ortopaedic Fixators. Accordingly, the stress distribution has been computed by finite-element analysis. The analyses were performed under an axial, variable loaded boundary conditions, different fracture sizes and different value of a distance between bone and external fixator device to study the stress distribution. The results show that stresses in the external fixator device are higher at the beginning of fracture healing process, afterwards gradually are reduced throughout the healing process. The analyses were carried out using the commercial package CATIA P3 V5R11. This allowed to accomplishes three-dimensional model more similar to the geometrical architecture of the long bone as well as of the external fixator. However, the accuracy of the results depends not only on the quality of the model geometry but also on the material properties assigned to the model components as well as on the accuracy in the simulation of the finite element model and the optimized mesh generation.

2

Fracture Healing as a Process of Mechanical Changes of the Bone Tissue

Sadzyński I.

Machine Dynamics Problems

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2004

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Vol. 28, No. 4

95-100

EN

The paper presents methods and results of the assessment of elasticity modulus changes during fracture healing. Long bone fractures can be healed using external fixators - devices that stiffy fix fracture fragments using parallel to the bone, attached with pins frame. This method affords to take profits both from healing and diagnostics of fracture during osteogenesis. Osteogenesis can be precisely determined with mechanical properties like strength and elasticity inside the fracture slot. The treatment of long bone fractures by external fixators affords a unique opportunity to control the healing of the fracture by measuring the tension on the frame, that occurs under the load given to the bone and rely on the mechanical properties of the fracture. Elasticity modulus can be one of the best description methods of mechanical properties of the bone. It can also be used for more precise and direct description of changes of mechanical properties inside the fracture slot.

3

Mechanical properties and calcification during healing of fracture treated by external fixation

Jasińska-Choromańska D., Sadzyński I.

Elektronika : konstrukcje, technologie, zastosowania

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2004

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Vol. 45, nr 8-9

85-87

EN

Long bone fractures can be healed using external fixators - devices that stiffly fix fracture fragments using parallel to the bone, attached with pins frame. This method affords to take profits both from healing and diagnostics of fracture during osteogenesis. The treatment of long bone fractures by external fixators affords a unique opportunity to control the healing of the fracture by measuring the tension on the frame, that occurs under the load given to the bone and rely on the mechanical properties of the fracture. Elasticity modulus can be one of the best descrption methods of mechanical properties of the bone. It can also be used for more precise and direct description of changes of mechanical properties inside the fracture slot. The paper presents methods and results of the assessment of changes of mechanical properties during fracture healing in comparison with the process of calcification.

PL

Złamania kości długich mogą być leczone z wykorzystaniem osteosyntezy zewnętrznej - urządzeń, które sztywno utrzymują odłamy kostne w odpowiedniej pozycji za pomocą przymocowanej do kości z wykorzystaniem wkrętów ramy. Metoda ta wykorzystana może być zarówno do leczenia jak i do diagnozowania procesu leczenia. Leczenie z wykorzystaniem stabilizacji zewnętrznej pozwala na kontrolę procesu zrostowego przez pomiar obciążeń przenoszonych przez ramę stabilizatora pojawiających się podczas zadawania obciążeń na kość i zależnych od właściwości mechanicznych szczeliny złamania. Moduł sprężystości może być jedną z najlepszych metod opisu własności mechanicznych kości. Może być również użyty do opisu zmian własności mechanicznych szczeliny złamania. Artykuł przedstawia metodę i rezultaty oceny zmian własności mechanicznych szczeliny złamania w porównaniu z procesem mineralizacji tkanki podczas leczenia złamania.

4

Monitoring Techniques of Bone Fracture Healing Using External Fixators

Jasińska-Choromańska D., Sadzyński I.

Engineering Transactions

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2003

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Vol. 51, iss.2-3

255-265

EN

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.

5

Heat Transfer Problems in Orthopaedics

Stańczyk M., Telega J.J.

Engineering Transactions

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2003

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Vol. 51, iss.2-3

267-306

EN

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.

6

A New Type of External Fixation

Jasińska-Choromańska D., Deszczyński J.

Engineering Transactions

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2003

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Vol. 51, iss.2-3

241-254

EN

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.