异种骨内固定器力学性能的实验研究

目的了解牛骨材料及其构件的力学强度[抗拉、抗压、抗折(弯曲)和抗扭(剪切)强度].方法将材料分为天然、处理和构件(即产品)三组并制成标准试件,用规定设备按标准方法进行检测.结果(1)牦牛股骨拉伸、压缩、抗折、扭转极限应力分别为106.35±3.45、127.60±2.65、225.9±4.1、53.45±1.55(MPa),胫骨拉伸、压缩、抗折、扭转极限应力分别为114.96±1.46、184.75±3.25、211.35±2.45、51.9±0.5(MPa).湖区水牛胫骨拉伸、压缩、抗折、扭转极限应力分别为1 28.1±11、195.8±9.4、167.4±1 2.7、54.25±0.75(MPa).(2)E0气薰灭菌对牛骨材料的力学性能无明显影响,幅照灭菌对牛骨材料的力学性能稍有影响.(3)处理后,牛骨螺钉、圆钉的抗折强度较材料有所降低,而抗拉强度、抗压强度、抗扭强度变化不大.结论牛骨是一种力学性能良好,适合制作内固定构件的高强度生物材料.     

异种骨内固定器力学性能的实验研究

目的 了解牛骨材料及其构件的力学强度[抗拉、抗压、抗折(弯曲)和抗扭(剪切)强度]。方法 将材料分为天然、处理和构件(即产品)三组并制成标准试件,用规定设备按标准方法进行检测。结果 (1)牦牛股骨拉伸、压缩、抗折、扭转极限应力分别为106.35±3.45、127.60±2.65、225.9±4.l、53.45±1.55(MPa),胫骨拉伸、压缩、抗折、扭转极限应力分别为114.96±1.46、184.75±3.25、211.35±2.45、51.9±0.5(MPa)。湖区水牛胫骨拉伸、压缩、抗折、扭转极限应力分别为128.1±11、195.8±9.4、167.4±12.7、54.25±0.75(MPa)。(2)EO气熏灭菌对牛骨材料的力学性能无明显影响,幅照灭菌对牛骨材料的力学性能稍有影响。(3)处理后,牛骨螺钉、圆钉的抗折强度较材料有所降低,而抗拉强度、抗压强度、抗扭强度变化不大。结论 牛骨是一种力学性能良好,适合制作内固定构件的高强度生物材料。     

臀肌挛缩症的生物力学机制探讨

目的　探讨臀肌挛缩症患者临床表现的生物力学机制。方法　切取手术中得到的臀肌挛缩带及新鲜病尸的臀肌制成肌纤维束标本 ,在MTS生物力学测试机上测定其拉伸的力学性质。结果　臀肌挛缩带拉伸的弹性模量、极限强度和极限应变分别为 (2 .73 2± 0 .792 )N mm2 ,(1 48.3 2± 3 .84)MPa ,0 .896± 0 .3 1 5。而正常臀肌的弹性模量、极限强度和极限应变分别为 (0 .1 43± 0 .0 2 4)N mm2 ,(1 0 .5 0± 1 .69)MPa ,1 .43 4± 0 .40 2。两者间均有显著差异。结论　臀肌挛缩后 ,其强度和刚度增大 ,而弹性则减小 ,这是引起一系列临床表现的力学基础     

医用连续碳纤维增强聚烯烃复合材料的生物力学特性测试

目的通过对医用连续碳纤维增强聚烯烃复合材料的生物力学测试,了解其作为硬组织修复材料的力学性能。方法对25根连续碳纤维增强聚烯烃复合材料棒进行拉伸、压缩、弯曲及剪切性能测试,得出该材料的最大载荷、极限强度、弹性模量、泊松比及延伸率。结果极限强度中,拉伸强度(561.11±14.24)MPa,压缩强度(341.91±1.71)MPa,弯曲强度(715.86±19.26)MPa,剪切强度(58.20±15.28)MPa。弹性模量(弯曲)(43.33±1.17)GPa;泊松比0.314±0.005;延伸率(18.20±0.55)%。结论医用连续碳纤维增强聚烯烃复合材料具有良好的生物力学特性,能满足硬组织修复的生物力学要求。     

胫骨远端骨折三种内固定方式的有限元分析

背景：目前对比3种内固定技术治疗胫骨远端骨折生物力学特性差异的研究较少。目的：比较胫骨远端骨折经胫骨内侧锁定钢板、专家级髓内钉和逆行髓内钉固定后生物力学特性的差异。方法：基于SAWBONES第4代人工复合胫骨模型的CT数据,利用三维重建技术构建胫骨远端骨折数字模型(AO/ASIF 43-A3型),在此基础上模拟胫骨内侧锁定钢板、专家级髓内钉和逆行髓内钉3种内固定方式;采用轴向压缩及扭转2种载荷工况分别对3组植入装配体模型进行有限元分析,比较三者的应力分布、应力峰值及骨折间隙位移变化的差异。结果与结论：(1)3组内固定物加载2种载荷工况时,专家级髓内钉组在扭转工况下应力峰值在未锁定的主钉孔处,为283.53 MPa;胫骨内侧锁定钢板组在扭转工况下应力峰值位于第3颗螺钉上,为913.07 MPa;逆行髓内钉组在扭转工况下应力峰值在第2个主钉孔处,为435.42 MPa;逆行髓内钉组内踝处主钉孔的周围皮质骨应力峰值出现在较高的轴向压缩工况下,峰值为55.34 MPa;(2)在骨折间隙位移方面,加载轴向压缩载荷时,专家级髓内钉组4个区域的切向位移最高;胫骨内侧锁定钢板组4个区域的轴向位移最高,...     

医用硬组织黏接胶黏接胫骨中段蝶形骨折的生物力学研究

在粉碎性骨折的治疗中 ,数目较多的骨折碎块的固定仍是一个临床常见的难题。医用硬组织黏接胶是治疗粉碎性骨折的又一新方法 .采用完整新鲜人胫骨、骨块缺失的新鲜人胫骨、黏接后的新鲜人胫骨在扭转、三点弯曲、压缩等状态下的应力 -应变指标变化 ,研究医用硬组织黏接胶黏接人胫骨蝶形骨块后的力学指标的改变。在弯曲、扭转、压缩等实验中 ,胫骨中段的蝶形骨缺损 ,显著减弱了胫骨的抗弯曲、抗扭转、抗压缩的强度。在扭转实验中 ,完整胫骨的扭距大于黏接后的胫骨 ,黏接后胫骨的扭距大于缺损的胫骨。在压缩实验中 ,胶体断裂前 ,完整胫骨的压缩曲线斜率大于黏接后的胫骨的压缩曲线斜率 (P<0 .0 1) ,黏接后胫骨压缩曲线斜率大于缺损胫骨的压缩曲线斜率 ,并有统计学显著性差异 (P<0 .0 5 )。三点弯曲实验中 ,在胶体断裂前 ,完整胫骨的曲线斜率与黏接后的胫骨无显著差异 (P>0 .0 5 ) ,黏接后胫骨与缺损的胫骨曲线斜率有显著差异 (P<0 .0 5 )。黏接后的胫骨 ,其弹性模量、刚度系数与完整的胫骨无显著差异 (P>0 .0 5 )。医用硬组织黏接胶黏接蝶形骨块后 ,能显著提高其抗弯曲、抗扭转、抗压缩应力。在临床操作中 ,可以最大程度上减少骨折碎块固定时周围的软组织剥离 ,有利于骨折的愈合     

胫股关节半月板松弛函数的实验研究

目的　研究正常国人急性外伤致死的成人新鲜尸体半月板的力学性质 ,为临床提供生物力学参数。方法　对 5具正常国人新鲜尸体胫股关节半月板的一维拉伸力学性能和拉伸应力松弛粘弹性力学性质进行测试。结果　得出了半月板一维拉伸的破坏载荷、伸长比、Lagrange张应力、La grange张应变等实验数据。以多项式用最小二乘法对拉伸实验数进行拟合 ,得出了半月板的应力 应变关系表达式和应力 应变曲线。获得了半月板应力松弛曲线和数据 ,归一化应力松弛函数数据和曲线 ,以及半月板的G(t)表达式。根据准线性理论还得出了髌骨软骨的松弛函数K(λ、t) =G(t)T(e) (λ)的表达式。结论　髌骨软骨单向拉伸最大载荷为 40± 3N ,伸长比为 1 .3 69± 0 .0 48,张应力为 7.2 7± 0 .5 9MPa ,应变为 43 .8± 6.6%。应力松弛主要发生在 1 2 0 0s以内。应力松弛曲线是以对数关系变化的。     

髌骨软骨拉伸应力松弛蠕变实验研究

目的　研究正常国人 8具新鲜尸体髌骨软骨的力学性质 ,为临床提供生物力学参数。方法　对正常国人新鲜尸体髌骨软骨一维拉伸力学性能和拉伸应力松弛、蠕变粘弹性力学性质进行实验研究。结果　获得了髌骨软骨一维拉伸的破坏载荷、伸长比、张应力、张应变等测试结果 ,以多项式用最小二乘法对拉伸实验数据进行拟合 ,得出了半月板的应力 -应变关系表达式和应力 -应变曲线。还得出了应力松弛、蠕变数据、曲线和归一化应力松弛函数、归一化蠕变函数数据、曲线。对实验数据以最小二乘法进行处理 ,得出了G(t)表达式 ,根据准线性理论得出了半月板的松弛函数K(λ、t)=G(t)T(e) (λ)的表达式。结论　髌骨软骨单向拉伸最大载荷为 3 8.5 4± 4.1 8N ,伸长比为 1 .3 1 2± 0 .0 1 8,张应力为 6.65± 0 .83MPa ,应变为 3 4.0± 3 .6%。应力松弛曲线是以对数关系变化的 ,蠕变曲线是以指数关系变化的     

化学发光免疫法与RIA法测定人血清抗TgAb和抗TpoAb结果的比较

比较CLIA和RIA法测定抗甲状腺球蛋白抗体 (抗TgAb)和抗甲状腺过氧化物酶抗体 (抗TpoAb)的临床应用意义。对经临床诊断甲状腺功能检查及病理证实的 37例慢性淋巴细胞性甲状腺炎患者 ,30例甲亢患者及36例患有内分泌疾病的患者 (包括甲状腺结节、甲状腺癌、糖尿病及库兴氏综合征 )和 35名正常人 ,用CLIA和RIA两种方法分别测定其血清的抗TgAb和抗TpoAb水平 ,并进行比较。结果表明 :(1 )CLIA和RIA法的批内变异分别为 3.0 %和 1 0 .0 % ,批间变异分别为 3.9%和 1 5 .0 % ;(2 )正常人抗TgAb水平分别为CLIA法是 2 5 .9± 9.6U/mL ;RIA为 1 1 .2± 2 .8% ,抗TpoAb水平分别为CLIA法是 31 .4± 6 .7U/mL ;RIA是 8.7± 3.0 % ;(3)慢性淋巴细胞性甲状腺炎患者分别用CLIA法测定抗TaAb为 2 92 .6± 334.1U/mL(1 7例 ) ,RIA为 5 6 .4±1 1 .2 % (2 1例 )。而用CLIA法测定抗TpoAb为 5 0 4 3.3± 31 96 .1U/mL(1 7例 ) ,RIA为 35 .4± 6 .9% (2 1例 ) ,该结果显示CLIA法所测抗TgAb和抗TpoAb水平均明显高于正常人 (P <0 .0 0 1 ) ,特别是抗TpoAb水平比正常人高百倍以上 ,说明其特异性更高 ;(4 )甲亢患者及内分泌病患者 ,用CLIA法测定抗TgAb为 2 0 2 .3±5 0 6 .3U/mL和 2 8.7± 1 5 .0U/mL ;用RIA法为 2 8.8± 2 0 .2 %和 1     

颈椎旋转手法对兔颈动脉粥样硬化血管 拉伸力学特性的影响

目的 研究颈椎旋转手法对兔颈动脉粥样硬化血管拉伸力学特性的影响,为颈椎旋转手法的安全性提供依据。方法 20只雄性新西兰兔随机分为2组,每组各10只,均饲高脂饮食12周建立动脉粥样硬化动物模型。12周后对实验组兔行颈椎旋转手法,每日左、右各旋转1次,共4周;对照组不作手法处理。手法结束后处死兔,取双侧颈动脉,利用生物组织材料力学试验机测定颈动脉拉伸最大载荷、最大形变、平均载荷、弹性模量和断裂延伸率等指标以及输出应力—应变曲线。结果 实验组颈动脉拉伸最大载荷(1.36±0.35) N,最大形变(6.84±2.08) mm,平均载荷(0.44±0.30) N,弹性模量(4.30±2.66) MPa,断裂延伸率(83.08±51.32)%;对照组颈动脉拉伸最大载荷(2.92±0.65) N,最大形变(9.23±2.62) mm,平均载荷(1.17±0.63) N,弹性模量(3.71±0.60) MPa,断裂延伸率(154.19±34.32)%。其中,实验组颈动脉拉伸的最大载荷、平均载荷和断裂延伸率明显小于对照组（P<0.05）;而最大形变以及弹性模量在两组中差异无统计学意义（P>0.05）。结论 经颈椎旋转手法后,颈动脉粥样硬化血管的拉伸力学特性下降,应注意颈椎旋转手法操作的力度和幅度,以免伤及颈动脉。     

股骨头松质骨力学性质实验研究

目的 研究股骨头松质骨力学性质，为临床提供生物力学参数。方法 对正常国人新鲜尸体股骨头松质骨的拉伸、压缩、扭转、剪切、弯曲、冲击力学性能进行实验研究。结果 得出了股骨头松质骨的拉伸、压缩破坏载荷、强度极限、弹性模量，扭转破坏扭矩、扭转剪切强度极限，弯曲破坏载荷、弯曲强度极限、剪切破坏载荷、剪切强度极限，冲击功、冲击韧性等测试指标的实验结果。结论 股骨头松质骨抗压强度大于抗拉强度，压缩弹性模量大于拉伸弹性模量，扭转强度大于剪切强度，抗弯强度与抗压强度接近。     

波形钢板固定股骨骨折的生物力学实验研究与临床应用

本文采用7具人尸股骨标本骨折后采用波形钢板和普通钢板加以固定，对照比较了两种不同固定方式下轴向压缩、三点弯曲、扭转试验下的生物力学性能。结果表明：波形钢板的强度比普通钢板的强度大32％，刚度高33％，两者是显著性差异（P＜0．01）。同时试验证明：波形钢板固定的应力遮挡率小于普通钢板32．5％，有利于骨重建应力环境的改善，能加速食痂生长。两种钢板本身的强度和刚度也显示了前者优于后者。证明采用波形钢板是符合生物力学原则的，临床应用波形钢板治疗股骨干骨折20例，经5～16个月随访，优良率达94．7％。表明波形钢板是治疗股骨干骨折较好的内固定方法，值得推广应用。     

The dependence between the strength and stiffness of cancellous and cortical bone tissue for tension and compression: extension of a unifying principle

A strong positive correlation between the apparent ultimate strength and stiffness of bone tissue that can be expressed by a unified relationship has been observed for cortical bone in tension and low-density cancellous bone in compression. For practical purposes, the existence of a relationship between strength and stiffness is significant in that bone stiffness can be measured in vivo using non-invasive methods. It is generally accepted that bone strength is greater in compression than in tension whereas there is no substantial evidence that bone stiffness in compression is different from that in tension. This might suggest that compressive strength would relate to the stiffness, if at all, in a way that is different from tensile strength. In order to examine similarities and differences in the way strength is associated with stiffness between modes of loading and tissue type, we tested equine cortical bone and bovine cancellous bone in compression and examined these data together with previously reported data from compression testing of human cancellous bone as well as tensile testing of cortical bone from various sources. We have found for cortical bone that (i) the sensitivity of strength to stiffness is the same for tension and compression (p>0.75, ANCOVA), and (ii) the difference between the magnitudes of compressive and tensile strength for cortical bone is the result of an additive, rather than a multiplicative factor (52.1 MPa after adjusting to 1 microstrain/s, p<0.0001, ANOVA). High-density bovine tibial cancellous bone, on the other hand, has a steeper slope for its compressive strength-stiffness relationship than that for cortical bone and human cancellous bone, resulting in a transitional relationship between compressive strength and stiffness for a range of bone types and densities. Based on the current results and previous work, it is suggested that the offset strength in the compressive strength-stiffness relationship may be a direct manifestation of the difference between the compressive and tensile strengths of the bone material that constitutes the building blocks of the bone structure. Deviation of high-density cancellous bone compressive behavior from the other bone types and densities is attributed to stress distribution differences between the bone types.     

Structure, metallurgy, and mechanical properties of a porous tantalum foam

This study evaluated a porous tantalum biomaterial (Hedrocel) designed to function as a scaffold for osseous ingrowth. Samples were characterized for structure, Vickers microhardness, compressive cantilever bending, and tensile properties, as well as compressive and cantilever bending fatigue. The structure consisted of regularly arranged cells having struts with a vitreous carbon core with layers of CVI deposited crystalline tantalum. Microhardness values ranged from 240-393, compressive strength was 60 +/- 18 MPa, tensile strength was 63 +/- 6 MPa, and bending strength was 110 +/- 14 MPa. The compressive fatigue endurance limit was 23 MPa at 5 x 10(6) cycles with samples exhibiting significant plastic deformation. SEM examination showed cracking at strut junctions 45 degrees to the axis of the applied load. The cantilever bending fatigue endurance limit was 35 MPa at 5 x 10(6) cycles, and SEM examination showed failure due to cracking of the struts on the tension side of the sample. While properties were variable due to morphology, results indicate that the material provides structural support while bone ingrowth is occurring. These findings, coupled with the superior biocompatibility of tantalum, makes the material a candidate for a number of clinical applications and warrants further and continued laboratory and clinical investigation.     

国人胫骨松质骨力学性质的实验研究

本文对国人胫骨近端松质骨的拉伸、压缩、扭转、剪切、弯曲的宏观力学性质及实验方法进行了实验研究和探讨。得到了一系列相应的常规力学性质,以及回归分析所拟合的曲线关系。可为临床医学提供参考。     

Influence of preparation techniques to the strength of the bone–cement interface behind the flange in total knee arthroplasty

IntroductionRecent clinical studies show an increased risk of femoral loosening in high-flexion TKA. Loosening seems to occur behind the anterior flange, which is covering both cancellous bone and cortical bone. It is important to optimize the interface strength between cement and both bone types to increase femoral component fixation. This study was performed to determine the cement–cortical bone interface strength for different preparation techniques.Material and methodsA pure tensile and shear force was applied to interface specimens. The cortical surface area was prepared in three different ways: (1) Unprepared cortical bone with periosteum; (2) Periosteum removed and cortical bone roughened with a rasp; (3) Periosteum removed and three Ø3.2 mm holes drilled through the cortex. A reference group was added with a cancellous bone surface.ResultsThe interface tensile strength of Group 1 was 0.06 MPa and the shear strength was 0.05 MPa. For Group 2, respectively 0.22 MPa and 1.12 MPa. For Group 3, respectively 1.15 MPa and 1.77 MPa. For cancellous bone a tensile strength of 1.79 MPa and a shear strength of 3.85 MPa were measured.ConclusionThe strength of the cement–cancellous bone interface is superior to the cement–cortical bone interface. The preferred preparation technique of the cortical bone is to remove all the periosteum and drill holes through the cortex within the footprint of the anterior flange, to prevent cortical weakening.Clinical relevanceUltimately, the proposed preparation technique will lead to longer implant survival, particularly for prostheses which are used in the high-flexion range.     

正常人皮质骨压缩力学性能实验研究

本文对６例正常青年男性（平均年龄３０岁左右）新鲜股骨干中段皮质骨，沿外侧纵向及横向各截取３６个圆柱体标本，行标本轴向压缩力学性能试验，结果显示，股骨中段皮质骨在纵、横两个不同方向上的力学性能具有很大差异。在相同载荷水平下，沿股骨干轴线方向的弹性模量、屈服强度、极限强度、屈服应变均明显高于横向（垂直于股骨轴线方向）。纵、横向弹性模量、屈服强度、极限强度、屈服应变的比值分别为１．５７、１．８８、１．３５、１．４８（Ｐ＜０．０００１）。经统计学分析，沿纵向骨的能量吸收值也明显高于横向（Ｐ＜０．０００１）。充分证明皮质骨是一种各向异性的非均质材料，为临床上骨创伤移植、及固定器械的研制提供重要的实验数据。     

两种新型骨水泥的组织学和生物力学研究

我们研制了两种可被骨长入的骨水泥：一种是部分可吸收的吸水泥（ＰＲＣ）,以双酚α－甲基丙烯酸甘油酯（Ｂｉｓ－ＧＭＡ）为基质,混合硅铝陶瓷和可吸收性聚合体颗粒调制成;另一种是磷酸钙骨水泥（ＣＰＣ）,由磷酸三钙、一水磷酸二氢钙、二水磷酸二钙和黄原胶组成。将这两种骨水泥分别植入家兔股骨和胫骨髁的骨缺损中,植入后２、４、１２ 和２４周取材,进行组织学观察和生物力学测试。结果发现,ＣＰＣ组有递增的骨整合,伴有     

Characterization of bone cements prepared with functionalized methacrylates and hydroxyapatite

Bone cements prepared with methyl methacrylate and either methacrylic acid or diethyl amino ethyl methacrylate as comonomers were characterized by infrared spectroscopy, nuclear magnetic resonance, gel permeation chromatography, dynamic mechanical thermal analysis, and mechanical testing. Selected formulations containing these functionalized methacrylates were filled with hydroxyapatite and studied in terms of their properties in tension, compression and bending, and X-ray diffraction. It was found that residual monomer was not greatly affected by the presence of either acid or basic comonomers in the unfilled bone cements. In contrast, molecular weight, curing times, and glass transition temperature were composition dependent. For samples with acidic comonomer, a faster curing time, higher molecular weight, and higher glass transition temperatures were observed with respect to those with the basic comonomer. X-ray diffraction revealed that the crystalline structure was not affected by the nature of comonomer in the bone cement while scanning electron microscopy showed that hydroxyapatite remained as clusters in the bone cement.The mechanical properties of filled bone cements depended mainly on composition and type of testing. Hydroxyapatite-filled bone cements fullfilled the minimum compressive strength (70 MPa) required for bone cement use. However, the minimum tensile strength (30 MPa) was only fullfilled by cements prepared without comonomer and those containing methacrylic acid. The minimum bending strength requirement (50 MPa) was not satisfied by any of the formulations studied.