Accurate bone registration in knee MR images

Changes of the cartilage morphology over time can tell the progression of osteoarthritis (OA) and show particular promise for evaluating the efficacy of disease-modifying OA drugs. Hence, cartilage matching is required prior to cartilage morphology comparison. An accurate cartilage matching allows one to ensure longitudinal focal and local changes of cartilage morphology due to OA. The method described in this article meets this need. The proposed method consists of three steps. First, the knee femur surfaces are aligned, using the principal axes transformation to correct for different knee joint positions and orientations in the magnetic resonance (MR) scanner. Second, we present a global registration algorithm based on Lipschitz optimization theory for accurately identifying the corresponding points of the knee femur surface. Third, the rigid transformation of the knee femur surface registration is applied to the cartilage surface. Our registration algorithm is efficient and robust, and its performance is evaluated on MR images of pig knees.     

Preparation for femur prosthesis of ceramic-metal combination artificial hip joint

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狗股骨近侧端动脉血液供应的初步观察

应用动脉灌注法，观察股骨近侧端动脉血液供应有关的动脉血管来源，分支及走向，观察结果表明，供应股骨近侧端的血管主要有5条，股深动脉，旋股内动脉，旋股外动脉，臀前动脉和臀后动脉，在以上动脉中旋股内动脉是最主要的供血动脉，股后动脉后部发出的升支与臀后动脉，股深动脉和旋股内动脉的肌支在股后肌群中存在大量吻合支，故可认为，股后动脉也与股骨近侧端血液供应有关。     

锶锌共掺杂磷酸八钙微球制备及其骨修复性能

本文研究了锶、锌共掺杂磷酸八钙多孔微球(Sr/Zn-OCP)的制备及其体内成骨生物学效应。实验运用湿化学合成工艺制备了粒径为105μm、280μm和500μm三种单分散微球颗粒材料,然后再考察微球材料对大白兔股骨缺血性坏死骨缺损的再生修复效应以及微球颗粒度对缺损修复效率的影响规律,运用理化表征与组织学分析考察了微球的微结构和骨组织修复特性。结果显示,利用低浓度聚丙烯酸可以诱导多层化尺度均一的Sr/Zn-OCP多孔微球颗粒形成,并且通过改变反应溶液的搅拌速率可以改变微球的尺度大小;同时,三种粒度微球堆积体均可见骨缺损内新骨再生,但是粒度最大的500μm微球修复骨缺损效率最高,在微球植入术后10、16周时新骨再生率达到37%和62%。以上研究结果表明多孔性Sr/Zn-OCP微球具有优良的生物活性效应,在解决病理性骨缺损再生修复方面具有良好应用价值。     

近端股骨的结构模拟

利用MullenderMG ,HuiskesR和WeinansH提出的骨自我组织控制过程 ,采用有限元与骨自优化理论相结合的方法来模拟近端股骨的结构 ,其结果是消除了早期模型中常见的方格盘现象 ,并且所预测的近端股骨的结构与实际结构非常吻合。     

Patient‐Specific Finite Element Modelling and Validation of Porcine Femora in Torsion

The accuracy of biomechanical simulation has been improved by using high‐resolution computed tomography (CT) to define the geometry and material parameters. This technique has been used to assess numerous systems, including the mechanical properties of bone, fixation techniques post‐fracture and the performance of bone microarchitecture. In this study, a semi‐automated process for converting CT data into finite element (FE) models was used to model the mid‐shaft (diaphysis) of porcine femoral samples under sub‐maximal torsional and compressive load. Physical validation was undertaken to investigate if the all‐important geometry and material property mapping functioned correctly. Porcine femoral specimens were imaged using contiguous helical CT, which was converted to FE models using ScanIP from Simpleware, Exeter, UK. The heterogeneous material properties were estimated using density–elasticity relationships proposed in literature for human bone samples. Laboratory testing performed favourably, with a linear strain response validating the use of the array of linear material models used in simulation. The simulation procedure also performed well. Linear regression and mean error calculation demonstrated accurate correlation between predicted (from simulation) and observed (measured within the laboratory) results that offered improvement over the accuracy within comparative testing for human samples. Using FE modelling on a patient‐specific basis offers potential in a number of scenarios, including the determination of injury risk and design of protective equipment. The increased accessibility of animal samples allows large‐scale fracture testing of complex loading mechanisms and the potential to consider younger animal samples (to investigate the behaviour of developing bone). Spiral fractures of long bones have been demonstrated to be an indicator of non‐accidental injury in children. Combining the increased accuracy in torsional simulation in this study with younger sample testing may be employed to attempt to determine the causes of fracture from post fracture scans, aiding in the diagnosis of non‐accidental injury.     

膳食纤维对大鼠钙平衡及骨生物力学性能的影响

目的：研究不同结构的膳食纤维对钙平衡及生物力学性能的影响。方法：以大鼠作为动物模型分组饲养,分别饲喂含有50 g/kg麦麸、纤维素、木聚糖、果胶、菊粉、魔芋胶及其混合物的饲料。利用原子吸收光谱法检测饲料、粪便、尿样、股骨中钙含量;利用电解质分析仪测定血清中的总钙、游离钙、结合钙浓度;用三点弯曲法检测股骨的最大载荷。比较摄入不同膳食纤维大鼠钙吸收、血钙水平、尿钙流失、钙保留率、骨钙含量、骨的生物力学性能等参数的差异。结果：在钙吸收率方面,麦麸、纤维素组高于木聚糖、果胶、菊粉、魔芋组,其中木聚糖和魔芋组与麦麸组具有极显著差异（P<0.01）;在尿钙日排出量方面,木聚糖和纤维素组低于其余各组;在钙保留率方面,果胶组最低,处于负钙平衡;在血清钙水平方面,麦麸组血清游离钙浓度和其余实验组没有显著性差异（P>0.05）,但麦麸组结合钙和总钙浓度均高于其他各组;在骨钙含量和骨生物力学性能方面,果胶组明显低于其他各组,木聚糖组的骨最大载荷高于其他各组。结论：麦麸和纤维素等低发酵型膳食纤维的肠道钙吸收率高于木聚糖、果胶、菊粉、魔芋等高发酵型膳食纤维;木聚糖有助于提高大鼠骨生物力学性能;不同膳...     

A new bone vascular perfusion compound for the simultaneous analysis of bone and vasculature

Bone is a highly vascular tissue, which plays an important role in bone development and healing. The ability to analyze both the bone and vasculature simultaneously can enhance the understanding of wound healing, development, and disease in bone. At present, analysis methods are limited in their ability to allow for this simultaneous analysis of bone and bone vasculature in three dimensions, without using the most recent dual‐energy computed tomography (CT) techniques. In this study, we present a new barium sulfate (BaSO₄) radiopaque vascular perfusion compound for performing postmortem microangiography with single‐beam microcomputed tomography (microCT), which allows for such simultaneous analysis. This compound differs from currently available contrast mediums due to (1) the high weight‐to‐volume ratio of BaSO₄ achieved, (2) small BaSO₄ aggregate size (<5 μm), (3) minimal additives, and (4) its miscibility with blood and saline. Most notably, it achieves a radiodensity of 2.4× that of cortical bone, with high perfusion of both the arterial and venous systems and the intervening capillary bed, resulting in an in vivo radiodensity that ranges from that of bone to titanium. Our results, verified using a rat femoral gap‐healing model, show that the compound is uniquely suited to high‐contrast imaging of the vasculature in the presence of undecalcified bone, with a versatility to be used in other tissues. Microsc. Res. Tech., 2010. © 2009 Wiley‐Liss, Inc.     

前交叉韧带单束移植隧道对胫/股骨承载影响的正交实验

利用膝关节处的密质骨和松质骨在CT成像中灰度值不同的特点,通过选取合适的阈值建立了含密质骨和松质骨的股骨和胫骨三维模型。同时,在视觉导航确定前交叉韧带(ACL)单束移植隧道起止点位置的条件下,按正交实验变换ACL移植隧道参数(孔径D、冠/矢状面上的倾角α/β),构建了含隧道股骨/胫骨模型。正交实验分为5个水平,依据在直立位胫/股骨处于静平衡时以等力传递载荷的原则,分别对含隧道的股骨及胫骨施加等值压缩和弯曲载荷进行有限元分析,得到隧道参数对股骨和胫骨应力影响特性。正交实验表明,三个参数对含隧道股骨的应力影响不明显(应力增量≤7.93%),但对含隧道的胫骨应力影响显著:受压缩载荷时冠/矢状面倾角α/β产生的应力增量分别达到39.10%和36.88%,而受弯曲载荷时矢状面倾角β引起应力增量最大可达24.66%。     

经皮撬拨与PFNA治疗老年骨质疏松性股骨粗隆间骨折效果

目的:探讨经皮撬拨与股骨近端防旋髓内钉(PFNA)治疗老年骨质疏松性股骨粗隆间骨折的效果。方法:选取我院手术治疗的90例老年骨质疏松性股骨粗隆间骨折患者进行回顾性分析,其中50例患者采用经皮撬拨联合PFNA治疗(观察组)、另外44例患者采用切开复位下PFNA治疗(对照组);对比两组的手术操作指标、骨折愈合情况、术后髋关节功能恢复及手术并发症率。结果:观察组患者的手术时间、切口长度、手术出血量、住院时间均低于对照组(P<0.05);观察组和对照组的骨折愈合时间差异无统计学意义(P>0.05);术后3个月,观察组患者的髋关节Harris评分高于对照组(P<0.05);术后6个月,观察组和对照组的髋关节Harris评分差异无统计学意义(P>0.05);术后3个月,观察组患者的髋关节活动度大于对照组(P<0.05);术后6个月,观察组和对照组的髋关节活动度差异无统计学意义(P>0.05);观察组患者的手术并发症率4.00%低于对照组的17.50%,差异具有统计学意义(P<0.05)。结论:经皮撬拨与PFNA治疗老年骨质疏松性股骨粗隆间骨折较切开复位PFNA具有手术创伤小、术后可早期功能锻炼促进髋关节功能恢复、手术并发症率更低的优势。