Name: proximal cadaveric femur preparation for fracture strength testing and quantitative ct-based finite element analysis
Uploaded: 2017-03-11T13:00:00
Description: Watch this Scientific Journal Video about Proximal Cadaveric Femur Preparation for Fracture Strength Testing and Quantitative CT-based Finite Element Analysis at JoVE.com

Gostaríamos de agradecer à Materiais e Estrutural Testing Núcleo Facilidade na Mayo Clinic para suporte técnico. Além disso, gostaríamos de agradecer a Lawrence J. Berglund, Brant Newman, Jorn op den Buijs, Ph.D., pela sua ajuda durante o estudo. Este estudo foi financiado pelo Fundo Grainger Inovação da Fundação Grainger.

NOTA: Todos os estudos apresentados neste protocolo foi aprovado pelo Institutional Review Board (IRB) na Mayo Clinic. Os ossos foram obtidas durante um período de 6 anos a partir de várias organizações. Todas as amostras foram recolhidas no prazo de 72 horas após a morte, envolvido em toalhas de solução salina saturada, e armazenadas a -20 ° C até à preparação. 1. medir a densidade mineral óssea usando DXA <ol><li> Retirar amostras mantidas à temperatura de -20 ° C congelad...

<ol>
	<li>Cristofolini, L., Schileo, E., Juszczyk, M., Taddei, F., Martelli, S., Viceconti, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanical+testing+of+bones:+the+positive+synergy+of+finite-element+models+and+in+vitro+experiments.">Mechanical testing of bones: the positive synergy of finite-element models and in vitro experiments.</a> Philos Trans A Math Phys Eng Sci. 368, 2725-2763 (2010).</li><li>Cartner, J. L., Hartsell, Z. M., Ricci, W. M., Tornetta, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Can+we+trust+ex+vivo+mechanical+testing+of+fresh-frozen+cadaveric+specimens?+The+effect+of+postfreezing+delays.">Can we trust ex vivo mechanical testing of fresh-frozen cadaveric specimens? The effect of postfreezing delays.</a> J Orthop Trauma. 25 (8), 459-461 (2011).</li><li>An, Y. H., Draughn, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Mechanical testing of bone and the bone-implant interface. , (1999).</li><li>van Haaren, E. H., van der Zwaard, B. C., van der Veen, A. J., Heyligers, I. C., Wuisman, P. I., Smit, T. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+long-term+preservation+on+the+mechanical+properties+of+cortical+bone+in+goats.">Effect of long-term preservation on the mechanical properties of cortical bone in goats.</a> Acta Orthop. 79, 708-716 (2008).</li><li>Shaw, J. M., Hunter, S. A., Gayton, J. C., Boivin, G. P., Prayson, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Repeated+freeze-thaw+cycles+do+not+alter+the+biomechanical+properties+of+fibular+allograft+bone.">Repeated freeze-thaw cycles do not alter the biomechanical properties of fibular allograft bone.</a> Clin Orthop Relat Res. 470 (3), 937-943 (2012).</li><li>Topp, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Embalmed+and+fresh+frozen+human+bones+in+orthopedic+cadaveric+studies:+which+bone+is+authentic+and+feasible?.">Embalmed and fresh frozen human bones in orthopedic cadaveric studies: which bone is authentic and feasible?.</a> Acta Orthop. 83 (5), 543-547 (2012).</li><li>Manske, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cortical+and+trabecular+bone+in+the+femoral+neck+both+contribute+to+proximal+femur+failure+load+prediction.">Cortical and trabecular bone in the femoral neck both contribute to proximal femur failure load prediction.</a> Osteoporos Int. 20 (3), 445-453 (2009).</li><li>Rezaei, A., Dragomir-Daescu, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Femoral+Strength+Changes+Faster+With+Age+Than+BMD+in+Both+Women+and+Men:+A+Biomechanical+Study.">Femoral Strength Changes Faster With Age Than BMD in Both Women and Men: A Biomechanical Study.</a> J Bone Miner Res. 30, 2200-2206 (2015).</li><li>Cristofolini, L., McNamara, B., Freddi, A., Viceconti, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+measured+strains+in+the+loaded+femur:+quantification+of+experimental+error.">In vitro measured strains in the loaded femur: quantification of experimental error.</a> J Strain Anal Eng Des. 32, 193-200 (1997).</li><li>Dragomir-Daescu, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Robust+QCT/FEA+models+of+proximal+femur+stiffness+and+fracture+load+during+a+sideways+fall+on+the+hip.">Robust QCT/FEA models of proximal femur stiffness and fracture load during a sideways fall on the hip.</a> Ann Biomed Eng. 39, 742-755 (2011).</li></ol>

Foi apresentado um protocolo de preparação óssea robusta para assegurar testes e QCT / FEA modelagem mecânica de força femoral em uma queda para o lado da configuração do quadril. Este método tornou-se o nosso protocolo padrão in-house. Ao longo de 6 anos, com diferentes pessoal, cerca de 200 fémures foram preparadas com sucesso seguindo este protocolo. Os resultados do protocolo inclui classificar condições ósseas usando DXA, descartando doenças metastáticas, fraturas anteriores, ou implantes usando raio...

Determining the true cadaveric proximal femoral fracture strength with mechanical testing is a destructive method that requires a rigorous testing approach for accurate measurements. In particular, proper bone preparation methods are necessary to maintain near in vivo integrity of the bones prior to mechanical fracture testing1. This is achieved by proper bone storage and minimizing handling at room temperature. This test data is extensively used to validate QCT/FEA models of femoral fracture which have the potential to be used clinically to understand the fracture risk, especially in osteoporotic patients. Unfortunately, there is no current standard procedure to prepare proximal femur samples for mechanical testing. A good testing procedure should ensure repeatability and reproducibility of the preparation process. Therefore, fixtures required for sample preparation need to be carefully designed and fabricated to minimize the likelihood of various testing errors. We also need to minimize the preparation time for which bone tissue is at room temperature and thus in danger of degradation with irreversible changes in mechanical properties. 
To this end, we have developed a procedure that preserves bone tissue across multiple preparation steps. This is important to ensure minimal exposure time at room temperature while also minimizing the number of freeze/thaw cycles which can affect tissue physical properties2. The entire procedure is long and nontrivial as the steps occurred over multiple weeks and required scheduling for scanning procedures and personnel availability. The steps included thawing bone samples, screening the samples using DXA scanning to obtain bone mineral density (BMD) values, X-ray to rule out any diseased specimens, and finally CT scanning to estimate distribution of bone mineral and femoral geometry. All the specimens were prepared for testing by removing extraneous soft tissues from the bone surface, cutting the femur to a length required for testing, and potting the femur in a desired orientation for simulating a sideways fall on the hip during subsequent testing. It is essential to keep the time period for all these operations as short as possible. A robust protocol is thus mandatory for consistent specimen preparation, tissue preservation between steps, and for reducing the overall preparation time. 
The aim of this paper is to present in detail the procedures involved in the preparation of femoral samples for subsequent mechanical testing under various conditions. Preservation of the bone tissue is crucial in this process and we achieved it by keeping specimens frozen between steps and keeping them carefully wrapped in saline saturated towels at all times except when scanning and mechanically testing the bones. Femora were also kept wrapped in saline wet towels during the steps involving PMMA curing to prevent dryness of the bone tissue.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>CT potting container and scanning fixture</td>
			<td>Internally manufactured</td>
			<td>N/A</td>
			<td>Custom designed and manufactured</td>
		</tr>
		<tr>
			<td>CT scanner</td>
			<td>Siemens</td>
			<td>Somatom Definition scanner (Siemens, Malvern, PA)</td>
			<td>CT scanning equipment</td>
		</tr>
		<tr>
			<td>Quantitative CT Phantom</td>
			<td>Midways Inc, San Francisco, CA</td>
			<td>Model 3 CT calibration Phantom</td>
			<td>Used for obtaining BMD values from Hounsfield units in the CT image</td>
		</tr>
		<tr>
			<td>Dual Energy X-ray Absorptiometry scanner</td>
			<td>General Electric</td>
			<td>N/A</td>
			<td>GE Lunar iDXA scanner for bone health or any similar BMD scanners</td>
		</tr>
		<tr>
			<td>Hygenic Orhodontic Resin (PMMA)</td>
			<td>Patterson Dental Supply</td>
			<td>H02252</td>
			<td>Controlled substance and can be purchased with proper approval</td>
		</tr>
		<tr>
			<td>Freezer</td>
			<td>Kenmore</td>
			<td>N/A</td>
			<td>This is a -20oC storage for bones</td>
		</tr>
		<tr>
			<td>X-ray scanner</td>
			<td>General Electric</td>
			<td>&#160;46-270615P1</td>
			<td>X-ray imaging equipment.&#160;&#160;</td>
		</tr>
		<tr>
			<td>X-ray films</td>
			<td>Kodak</td>
			<td>N/A</td>
			<td>Used to display x-ray images</td>
		</tr>
		<tr>
			<td>X-ray developer</td>
			<td>Kodak X-Omatic</td>
			<td>M35A X-OMAT&#160;</td>
			<td>Used for developing X-ray images</td>
		</tr>
		<tr>
			<td>X-ray Cassette</td>
			<td>Kodak X-Omatic</td>
			<td>N/A</td>
			<td>Used for holding x-ray films</td>
		</tr>
		<tr>
			<td>5-pound Rice Bags</td>
			<td>Great Value</td>
			<td>N/A&#160;</td>
			<td>Used for mimicking soft tissue during the DXA scanning process</td>
		</tr>
		<tr>
			<td>Physiologic Saline (0.9% Sodium Chloride)</td>
			<td>Baxter</td>
			<td>NDC 0338-0048-04</td>
			<td>Used for keeping samples hydrated</td>
		</tr>
		<tr>
			<td>Scalpels and scrapers</td>
			<td>Bard-Parker</td>
			<td>N/A</td>
			<td>Used to clean the bone from soft tissue</td>
		</tr>
		<tr>
			<td>Cast cutter</td>
			<td>Stryker</td>
			<td>810-BD001</td>
			<td>Used to cut femoral shaft</td>
		</tr>
		<tr>
			<td>Drilling machine</td>
			<td>Bosch</td>
			<td>N/A</td>
			<td>Used to drill the femoral shaft</td>
		</tr>
		<tr>
			<td>Fume Hood</td>
			<td>Hamilton</td>
			<td>70532</td>
			<td>Used for ventilation when using making PMMA</td>
		</tr>
	</tbody>
</table>

proximal cadaveric femur preparation for fracture strength testing and quantitative ct-based finite element analysis

testes de fratura Cadaveric é rotineiramente usado para entender os fatores que afetam a força do fêmur proximal. Porque ex vivo tecidos biológicos são propensos a perder as suas propriedades mecânicas ao longo do tempo, Preparação de amostras para o teste experimental deve ser realizada com cuidado para obter resultados confiáveis que representam as condições in vivo. Por essa razão, foi elaborado um protocolo e um conjunto de acessórios para preparar os espécimes femorais de tal forma que as suas propriedades mecânicas experientes alterações mínimas. Os fémures foram mantidos em um estado congelado, exceto durante as etapas de preparação e ensaios mecânicos. As medidas clínicas relevantes do total do quadril e fêmur densidade pescoço mineral óssea (DMO) foram obtidos com um densitômetro ósseo clínica dupla absorciometria de raios-X (DXA), e da geometria e distribuição de mineral óssea 3D foram obtidos utilizando CT com um fantasma de calibração para estimativas quantitativas baseadas nos valores de escala de cinzentos. Qualquer possível doença óssea, fratura, Ou a presença de implantes ou artefactos que afectam a estrutura óssea, foi descartada com exames de raios-X. Para a preparação, todos os ossos foram cuidadosamente limpos de tecido mole em excesso, e foram cortados e em vaso, com o ângulo de rotação interna de interesse. Um dispositivo de corte permitiu a extremidade distai do osso que se pretende cortar o fémur proximal, deixando a um comprimento desejado. Para permitir o posicionamento do colo do fêmur em ângulos prescritos durante a tarde tomografia computadorizada e ensaios mecânicos, os eixos proximais do fêmur foram envasadas em polimetilmetacrilato (PMMA), utilizando um dispositivo elétrico projetado especificamente para orientações desejadas. Os dados recolhidos a partir de nossas experiências foram então usados ​​para validação da tomografia computadorizada quantitativa (QCT) à base de análise de elementos finitos (FEA), como descrito em um protocolo diferente. Neste artigo, apresentamos o protocolo para a preparação óssea preciso para testes mecânicos e subsequente modelagem QCT / FEA. O actual protocolo foi aplicado com sucesso para preparar cerca de 200 cadfémures Averic ao longo de um período de tempo de 6 anos.

Os fémures de cadáveres foram enviados congelada e mantida a -20 ° C até à preparação começou. Digitalização DMO foi realizada utilizando um scanner DXA para medir total do quadril e pescoço DMO, bem como T-score para cada amostra (Figura 1). A T-score é o número de desvios padrão da DMO medidos comparados com os valores médios para indivíduos jovens e saudáveis. Ela pode variar de -2,5 ou inferior para ossos osteoporóticos, entre -1 e -2,5 para ossos o...

Watch this Scientific Journal Video about Proximal Cadaveric Femur Preparation for Fracture Strength Testing and Quantitative CT-based Finite Element Analysis at JoVE.com

Proximal Cadaveric Femur Preparation for Fracture Strength Testing and Quantitative CT-based Finite Element Analysis

Nós apresentamos um protocolo robusto sobre como preservar com cuidado e preparar fémures cadavérico para testes de fratura e tomografia computadorizada quantitativa. O método oferece um controle preciso sobre as condições de entrada para o propósito de determinar as relações entre a densidade mineral óssea, resistência à fratura, e definir finito geometria e propriedades elemento do modelo.

Proximal Cadaveric Femur Preparação para Análise de Elementos Finitos baseado no CT Fracture Força Testes e Quantitativa

Cadaveric fracture testing is routinely used to understand factors that affect proximal femur strength.  Because ex vivo biological tissues are prone to ...

Research

JoVE Journal

Medicine

Quantitative Autonomic Testing

Teste Autônomo quantitativa

Disorders associated with dysfunction of autonomic nervous system are quite common yet frequently unrecognized. Quantitative autonomic testing can be ...

Medicina

Manual Muscle Testing:  A Method of Measuring Extremity Muscle Strength Applied to Critically Ill Patients

Teste muscular manual: um método de medir a força muscular Extremidade Aplicada à pacientes criticamente enfermos

Survivors of acute respiratory distress syndrome (ARDS) and other causes of critical illness often have generalized weakness, reduced exercise tolerance, ...

Method to Measure Tone of Axial and Proximal Muscle

Método para medir tom de músculo axial e proximal

The control of tonic muscular activity remains poorly understood.  While abnormal tone is commonly assessed clinically by measuring the passive resistance ...

Quantitative Analysis of Chromatin Proteomes in Disease

Análise quantitativa de proteomas cromatina na Doença

In the nucleus reside the proteomes whose functions are most intimately linked with gene regulation. Adult mammalian cardiomyocyte nuclei are unique due ...

Sequential In vivo Imaging of Osteogenic Stem/Progenitor Cells During Fracture Repair

Sequential In vivo Imaging of Osteogenic Stem/Progenitor Cells During Fracture Repair

Seqüente<em&gt; In vivo</em&gt; Imagem de osteogênicas células-tronco / progenitoras durante o reparo de fratura

Bone turns over continuously and is highly regenerative following injury. Osteogenic stem/progenitor cells have long been hypothesized to exist, but in ...

Adjustable Stiffness, External Fixator for the Rat Femur Osteotomy and Segmental Bone Defect Models

A rigidez ajustável, Fixador Externo para os Rat Femur Osteotomia e segmentar defeito ósseo Models

The mechanical environment around the healing of broken bone is very important as it determines the way the fracture will heal. Over the past decade there ...

Adapted Resistance Training Improves Strength in Eight Weeks in Individuals with Multiple Sclerosis

Treinamento da resistência adaptada melhora a força em oito semanas em indivíduos com esclerose múltipla

Hip weakness is a common symptom affecting walking ability in people with multiple sclerosis (MS). It is known that resistance strength training (RST) can ...

In Vivo Evaluation of Fracture Callus Development During Bone Healing in Mice Using an MRI-compatible Osteosynthesis Device for the Mouse Femur

In Vivo Evaluation of Fracture Callus Development During Bone Healing in Mice Using an MRI-compatible Osteosynthesis Device for the Mouse Femur

Na Vivo Avaliação do desenvolvimento de calo de fratura durante a consolidação óssea em ratos usando um dispositivo de osteossíntese compatível com MRI para o fêmur de Mouse

Endochondral fracture healing is a complex process involving the development of fibrous, cartilaginous, and osseous tissue in the fracture callus. The ...

Muscle Imbalances: Testing and Training Functional Eccentric Hamstring Strength in Athletic Populations

Desequilíbrios musculares: Teste e treinamento de força funcional da limitação excêntrico em populações atléticas

Many hamstring injuries that occur during physical activity occur while the muscles are lengthening, during eccentric hamstring muscle actions. Opposite ...

Fracture Apparatus Design and Protocol Optimization for Closed-stabilized Fractures in Rodents

Fratura aparelhos Design e otimização de protocolo para fraturas fechadas-estabilizado em roedores

The reliable generation of consistent stabilized fractures in animal models is essential for understanding the biology of bone regeneration and developing ...