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

Vi vil gerne takke Materialer og strukturel test Core Facility ved Mayo Clinic til teknisk support. Desuden vil vi gerne takke Lawrence J. Berglund, Brant Newman, Jorn op den Buijs, Ph.D., for deres hjælp i løbet af undersøgelsen. Denne undersøgelse blev støttet af Grainger Fornyelsesfonden fra Grainger Foundation.

BEMÆRK: Alle undersøgelser præsenteres i denne protokol blev godkendt af Institutional Review Board (IRB) på Mayo Clinic. Knoglerne blev opnået over en periode på 6 år fra forskellige organisationer. Alle prøver blev indsamlet inden for 72 timer død, svøbt i saltvand mættede håndklæder, og opbevares ved -20 ° C indtil forberedelse. 1. Måling Bone Mineral Density Brug DXA <ol><li> Fjern eksemplarer, der holdes ved -20 ° C fryser tø op ved stuetemperatur i ca. 24 timer; prø...

<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>

Vi præsenteret en robust knogle forberedelse protokol for at sikre mekanisk afprøvning og QCT / FEA modellering af femoral styrke i en sidelæns fald på hoften konfiguration. Denne metode blev vores standard in-house-protokol. I løbet af 6 år, med varierende personale, omkring 200 lårben lykkedes udarbejdet efter denne protokol. Resultaterne af protokollen omfatter klassificere knogle betingelser ved hjælp af DXA, udelukke metastatiske sygdomme, tidligere frakturer, eller implantater ved hjælp af røntgen, og f?...

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

Nekro fraktur test anvendes rutinemæssigt til at forstå faktorer, der påvirker proximal femur styrke. Fordi ex vivo biologisk væv er tilbøjelige til at miste deres mekaniske egenskaber over tid, modellen skal udføres forberedelse til eksperimentelle test omhyggeligt for at opnå pålidelige resultater, der repræsenterer in vivo betingelser. Derfor har vi designet en protokol og et sæt inventar til at forberede de femorale prøver således, at deres mekaniske egenskaber oplevet minimale ændringer. Femora blev holdt i frossen tilstand, undtagen ved tilberedningen trin og mekanisk prøvning. De relevante kliniske foranstaltninger af total hofte og lårbenshals knoglemineraltæthed (BMD) blev opnået med et klinisk dobbelt røntgenabsorptiometri (DXA) knogle densitometer, og 3D-geometri og distribution af knoglemineral blev opnået ved anvendelse CT med en kalibrering fantom for kvantitative skøn baseret på gråtone værdier. Enhver mulig knoglesygdom, frakturEller tilstedeværelsen af ​​implantater eller artefakter påvirker knoglestruktur, blev udelukket med X-ray scanninger. For forberedelse blev alle knogler omhyggeligt renset for overskydende blødt væv, og blev skåret og potteplanter på det interne rotation vinkel af interesse. En skærende fikstur tillod den distale ende af knoglen, der skal afskæres forlader den proximale femur ved en ønsket længde. For at tillade positionering af lårbenshalsen på foreskrevne vinkler under senere CT scanning og mekanisk prøvning, blev de proximale femorale aksler pottet i polymethylmethacrylat (PMMA) med en armatur designet specielt til de ønskede orienteringer. De indsamlede fra vores eksperimenter data blev derefter anvendt til validering af kvantitativ computertomografi (QCT) -baseret finite element analyse (FEA), som beskrevet i en anden protokol. I dette manuskript, præsenterer vi protokol for den præcise forberedelse knogle til mekanisk afprøvning og efterfølgende QCT / FEA modellering. Den nuværende protokol blev anvendt med succes til at forberede omkring 200 cadaveric lårben over en 6-års periode.

De kadaver lårben blev afsendt frosset og holdt ved -20 ° C indtil fremstilling begyndte. BMD scanning blev udført under anvendelse af en DXA scanner til at måle total hofte og BMD samt T-score for hver prøve (figur 1). En T-score er antallet af standardafvigelser af målte BMD sammenlignet med gennemsnitlige værdier for unge raske forsøgspersoner. Det kan være lige fra -2,5 eller lavere for osteoporotiske knogler, mellem -1 og -2,5 for osteopeniske knogler og h?...

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

Vi præsenterer en robust protokol om, hvordan man omhyggeligt bevare og forberede Nekro lår for fraktur test og kvantitativ computertomografi billeddannelse. Fremgangsmåden tilvejebringer præcis kontrol over input betingelser med henblik på at bestemme forholdet mellem knoglemineraltæthed, brudstyrken, og definere finite element model geometri og egenskaber.

Proksimal afdød Lårben Forberedelse til brudstyrken Test og Quantitative CT-baserede Finite Element Analysis

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

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

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

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

Metode til at måle tone Axial og proksimal muskelsvaghed

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

Kvantitativ analyse af kromatin Proteomes i Disease

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

Sekventiel<em&gt; In vivo</em&gt; Imaging af Osteogene Stem / stamceller Under frakturreparation

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

Justerbar Stivhed, Eksterne fixator for Rat Femur osteotomi og Segmentoplysninger knogledefekt Modeller

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

Tilpasset Resistance Training Forbedrer Styrke i otte uger i Personer med multipel sklerose

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

In Vivo Evaluering af fraktur Callus udvikling under knogleheling i mus ved hjælp af en Mr-kompatible osteosyntese enhed for musen lårben

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

Muskel ubalancer: Test og uddannelse funktionelle excentrisk forstrækning styrke i Athletic populationer

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

Fraktur apparater Design og protokollen optimering for lukket-stabiliseret frakturer i gnavere

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