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

Biz teknik destek için Mayo Clinic Malzeme ve Yapısal Test Çekirdek Tesisi teşekkür etmek istiyorum. Ayrıca biz çalışma sırasında yardım için, Lawrence J. Berglund, Brant Newman, Jorn op den Buijs, Ph.D. teşekkür etmek istiyorum. Bu çalışma finansal Grainger Vakfı Grainger İnovasyon Fonu tarafından desteklenmiştir.

NOT: Bu protokol sunulan tüm çalışmalar Mayo Clinic Kurumsal Değerlendirme Kurulu (KİK) tarafından onaylanmıştır. Kemikler çeşitli kuruluşlardan 6 yıllık bir süre boyunca elde edildi. Tüm örnekler doymuş tuz havlu sarılır ve hazırlanana kadar -20 ° C&#39;de saklandı, ölüm 72 saat içinde toplanmıştır. 1. DXA Kullanarak Kemik Mineral Yoğunluğu Ölçümü <ol><li> yaklaşık 24 saat boyunca oda sıcaklığında erimeye -20 ° C dondurucuda tutuldu örnekleri ç...

<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>

Biz kalça yapılandırmasına bir yan sonbaharda femoral gücü mekanik test ve QCT / FEA modelleme sağlamak için sağlam bir kemik hazırlık protokolü sundu. Bu yöntem standart in-house protokol olmuştur. 6 yıl boyunca, değişen personel ile yaklaşık 200 femur başarıyla bu protokol izlenerek hazırlandı. protokolün sonuçları metastatik hastalıklar, önceki kırıklar, ya da X-ışını kullanan implantlar iktidar, DXA kullanarak kemik koşullarının sınıflandırılması ve mineral dağılımı ve s...

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

Kadavra kırık testi rutin olarak proksimal femur gücünü etkileyen faktörleri anlamak için kullanılır. Ex vivo olarak biyolojik dokular zaman içinde mekanik özelliklerini kaybetmeye eğilimlidirler için, deney testleri için hazırlanması dikkatli yapılmalıdır in vivo koşullarında temsil güvenilir sonuçlar elde etmek için, numune. Bu nedenle, biz onların mekanik özellikleri minimal değişiklikler yaşadı şekilde femur örnekleri hazırlamak için bir protokol ve demirbaşlar bir dizi tasarlanmış. femora Preparat adımları ve mekanik test sırasında donmuş halde tutuldu. total kalça ve femur boynu kemik mineral yoğunluğu (BMD) ilgili klinik önlemler klinik çift X-ışını absorpsiyometri (DXA) kemik dansitometre ile elde edilmiştir ve 3D geometri ve kemik mineral dağılımı kalibrasyon fantom için birlikte BT kullanılarak elde edilmiştir gri tonlama değerlere dayalı nicel tahminleri. Herhangi bir olası kemik hastalığı, kırıkYa da implantlar veya kemik yapısını etkileyen eserler varlığı, X-ışını tarama ile ekarte edildi. hazırlanması için, tüm kemik fazlası dikkatli, yumuşak doku temizlenmiştir ve ilgi iç dönme açısı kesilerek ekilmiş. Bir kesici armatürü kemiğin distal ucu istenilen uzunluğa proksimal femur bırakarak kesilmiş izin verdi. Daha sonra CT taraması ve mekanik test sırasında öngörülen açılarda femur boynu konumlandırma izin vermek için, proksimal femoral miller istenen yönelimler için özel olarak tasarlanmış bir fikstür kullanarak polimetilmetakrilat (PMMA) ekilmiş. Farklı protokolde tarif edildiği gibi deneylerimiz toplanan veriler daha sonra, sonlu eleman analizi (FEA) tabanlı kantitatif bilgisayarlı tomografi (QCT) doğrulanması için kullanılmıştır. Bu yazıda, mekanik test ve sonraki QCT / FEA modelleme için hassas kemik hazırlanması için protokol mevcut. Mevcut protokolü başarılı bir şekilde yaklaşık 200 cad hazırlanması için uygulandı6 yıllık süre zarfında averic femora.

Kadavra femora Dondurulmuş sevk ve hazırlama başlayana kadar -20 ° C&#39;de muhafaza edilmiştir. BMD tarama her numune (Şekil 1) için total kalça ve boyun KMY yanı sıra T-skoru ölçmek için bir DXA tarayıcı kullanılarak gerçekleştirilmiştir. A T-skoru genç sağlıklı bireylerde ortalama değerleri ile karşılaştırıldığında ölçülen BMD standart sapmaları sayısıdır. Bu osteoporotik osteopenik kemikler için -1 ve -2.5 arasında kemiklerin ...

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

Dikkatle korumak ve kırık testi ve kantitatif bilgisayarlı tomografi görüntüleme için kadavra femora hazırlamak için nasıl sağlam bir protokol mevcut. yöntemi, kemik mineral yoğunluğunda, kırılma dayanımı ilişkilerini belirlenmesi sonlu elemanlar modeli geometrisini ve özelliklerini tanımlamak amacıyla girdi koşullar üzerinde hassas kontrol sağlar.

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