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

私たちは、技術サポートのためのメイヨークリニックでの材料と構造Testingコアファシリティーに感謝したいと思います。また、我々は、研究中の彼らの助けのために、ローレンス・J・ベルグルンド、ブラントニューマン、ジョーンオペアンプデンBuijs、博士に感謝したいと思います。この研究は、財政グレインジャー財団からグレインジャーイノベーション基金によってサポートされていました。

注：このプロトコルで提示されたすべての研究はメイヨークリニックでの治験審査委員会（IRB）により承認されました。骨は様々な機関からの6年間にわたって得られました。全ての検体は、生理食塩水飽和タオルに包まれ、そして準備まで-20℃で保存し、死の72時間以内に採取しました。 1. DXAを用いて骨密度を測定<ol><li>約24時間室温で解凍し、-20℃の冷凍庫に保た標?...

<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>

私たちは、ヒップ構成の横秋に大腿骨強度の機械的試験及びQCT / FEAモデリングを確保するための強固な骨調製プロトコルを提示しました。この方法は、弊社の標準の社内プロトコルとなりました。 6年の歳月をかけて、様々な人材で、約200大腿骨は正常にこのプロトコルに従って調製しました。プロトコルの結果は、転移性疾患、以前の骨折、またはX線を使用してインプラントを除外、DXAを?...

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

死体の破壊試験を日常的に、近位大腿骨の強度に影響を与える要因を理解するために使用されます。 ex vivoでの生物学的組織は経時的にその機械的性質を失う傾向があるので、実験的試験のための準備を慎重に行わなければならない、インビボ条件下で表す信頼できる結果を得るために、検体。そのため、私たちはその機械的性質は、最小限の変更を経験したように、大腿骨の標本を準備するためのプロトコルや備品のセットを設計しました。大腿骨は、調製工程及び機械試験中以外は冷凍状態で維持しました。全股関節及び大腿骨頸部骨密度（BMD）の関連する臨床尺度は、臨床デュアルX線吸収測定（DXA）、骨密度計を用いて得られ、3Dジオメトリ及び骨ミネラルの分布は、較正ファントムのためでCTを用いて得られましたグレースケール値に基づいて定量的推定。すべての可能な骨疾患、骨折、またはインプラントまたは骨構造に影響を及ぼすアーチファクトの存在は、X線スキャンで除外されました。調製のために、すべてのボーンを慎重に余分な軟組織を洗浄し、そして関心の内部回転角にカットし、鉢上げました。切断器具は、骨の遠位端が所望の長さで近位大腿骨を残して遮断することを可能にしました。後でCTスキャンおよび機械的テスト中に所定の角度で大腿骨頸部の位置決めを可能にするために、大腿骨近位部シャフトは、所望の配向のために特別に設計された固定具を用いて、ポリメチルメタクリレート（PMMA）で鉢植えしました。我々の実験から収集されたデータは、その後、定量的コンピュータ断層撮影（QCT）の検証のために使用された別のプロトコルに記載のように、有限要素解析（FEA）をベース。本稿では、我々は機械的試験及びその後のQCT / FEAモデリングのための正確な骨の調製のためのプロトコルを提示します。現在のプロトコルは、成功し、約200 CADを作製するために適用されました6年の期間にわたるaveric大腿骨。

死体大腿骨は冷凍出荷され、準備が始まるまで-20℃で維持しました。 BMDスキャンは股関節頸部BMD並びに各試料についてのTスコア（ 図1）を測定するDXAスキャナを用いて行きました。 Tスコアは、若い健康な被験者の平均値と比較して測定されたBMDの標準偏差の数です。これは、骨減少症、骨や-1より正常な骨のためのより高いため-1と-2.5の間、骨粗しょう...

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

我々は慎重に維持し、破壊試験および定量的コンピュータ断層撮影用の死体大腿骨を準備する方法の堅牢なプロトコルを提示します。この方法は、骨密度、破壊強度との関係を決定し、有限要素モデルの幾何学的形状および特性を定義するために入力条件を正確に制御を提供します。

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

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