开槽法髓内针内固定术治疗猫、犬桡骨、胫骨骨折的探索

猫、犬桡的尺骨、胫腓骨骨折在临床上很常见。据报道,桡骨、尺骨常同时骨折约占骨折发病率的31％,多发生在骨的中部或远端1／3处,以横骨折和斜骨折居多;胫骨与腓骨骨折也常同时发生,多为骨干骨折,占骨折发病率的28％。桡骨尺骨、胫骨腓骨远端完全错位性骨折采用外固定效果较差,亦难找到合适的钢板内固定。     

LISS钢板治疗股骨远端骨折有限元建模及分析

目的建立LISS-DF治疗股骨远端骨折近端螺钉不同单双皮质固定的三维有限元模型,并进行初步生物力学分析。方法提取CT图片相关数据,利用自行编写程序生成命令流文件,建立完整股骨以及16个不同LISS-DF治疗股骨远端AO分型33-A3型骨折的实体模型（钢板和股骨不接触、螺钉分别固定于钢板和股骨）,进行网格划分。分析不同载荷作用下完整股骨和LISS钢板近端螺钉全双皮质固定治疗骨折的模型受力状况。结果建立了相关的有限元模型。不同载荷作用下,LISS钢板近端螺钉全双皮质固定模型和完整股骨的应力集中均位于股骨颈内侧和股骨干外侧中下1/3处。相同载荷作用下,LISS钢板近端螺钉全双皮质固定模型的股骨颈部最大等效应力值略减小,股骨干最大等效应力值明显减小。结论研究建立的三维有限元模型,为应用LISS治疗股骨骨折的生物力学分析提供了良好的实验平台和基础。从生物力学角度而言,LISS-DF近端螺钉全双皮质固定为治疗股骨远端复杂骨折的有效方法。     

肱骨有限元模型建立及生物力学分析

目的:以成人肱骨为例,将医学图像三维重建技术和有限元方法结合应用于正骨手法研究,建立正常肱骨有限元模型,验证模型的有效性并进行生物力学分析。方法:选择一位青年男性志愿者,对其上肢自尺桡骨上端至肱骨头进行连续断层扫描,得到CT图像,将CT数据导入MIMICS软件中,通过图像分割、三维重建和材料属性赋值,构建正常肱骨有限元模型,利用ANSYS软件进行力学分析,与文献中肱骨的生物力学数据相比较,以此验证模型的有效性。结果:建立了正常肱骨三维几何模型和有限元模型。利用ANSYS软件,对模型进行了有效性验证。所建模型物理特性与真实骨骼相近,能很好地反映骨骼的力学变化,实现手法的定量分析。结论:所建立的肱骨模型外形逼真、在不同载荷下的应力值与相关文献一致,可用作中医仿真系统中的虚拟骨折模型。     

安徽黄山中侏罗世蜥脚类恐龙一新属种

记述了发现于安徽省黄山市歙县中侏罗统洪琴组的蜥脚类恐龙一新属种:安徽黄山龙Huangshanlong anhuiensis gen.et sp.nov.。黄山龙保存了右侧肱骨和桡尺骨,对比研究发现可以将其归入马门溪龙科。黄山龙和马门溪龙科其他成员一样肱骨远端向外侧扭转25°并在其上有发育的附突,尺骨两前臂突发育并形成90°或略小的夹角。与马门溪龙科其他属种相比,黄山龙又具有独特的特征组合:肱骨近端长为肱骨长的36%,远端附突位于中部;桡骨为肱骨长的58%;尺骨为肱骨长的2/3,尺骨两臂突中的内前突更长,尺骨远端前面、外后面和内后面上都有棱嵴发育。黄山龙是安徽境内发现的第一个侏罗纪也是第2个恐龙化石种。     

两种方法治疗桡骨远端骨折的疗效比较研究

目的:比较采用T形钢板内固定和闭合复位石膏外固定这两种方法治疗桡骨远端骨折的疗效研究。方法:选取我院2008年3月至2011年12月间的76例桡骨远端骨折患者,并按照治疗方法不同分为2组,41例患者进行T形钢板内固定,其余35例患者进行复位后石膏外固定。并借助X线对比分析桡骨远端骨折复位前后及临床愈合时桡骨腕关节的掌倾角、尺偏角及桡骨轴向缩短长度变化等数据,并根据改良的Shea评定法对临床疗效进行比较。结果:针对桡骨远端不稳定型骨折的患者,T形钢板内固定组的优良率要优于石膏外固定组的疗效(P<0.05);而对于稳定性桡骨远端骨折的患者,两组之间的优良率没有明显差异(P>0.05)。结论:对于桡骨远端不稳定骨折的患者,应优先选择T形钢板内固定手术方法,而对于稳定性骨折患者这两种治疗方法均可采用。     

河南明港—始新世鸟类形态观察

本文记述了一发现于河南明港始新世较小型涉禽类的尺骨和胫跗骨远端化石。依据尺骨远端腱凹窄而浅,桡骨凹大,外侧具一纵沟和胫跗骨外关节髁外侧面中央有一窄纵嵴等特征定一新属种:张沟明港鹮Minggangiachanggouensis gen.et sp.nov. 明港鹮的时代为晚始新世,它代表迄今为止我国发现的鹳形目最早的鸟类。     

单端固定式下颌骨修复体的应力分析

目的:针对包括一侧髁状突的下颌骨缺损,通过有限元应力分析,了解单端固定式下颌骨修复体在功能运动时的受力与变形规律,以期寻求更加合理的修复体的设计和固定方式。方法:建立下颌骨断端和修复体的简易三维模型,模拟咀嚼运动,施加垂直方向载荷,进行有限元法应力分析,计算出该模型各组成部分的应力分布和受力变形。结果:在该模型加载时,延伸板基部和近断端处上部的螺钉颈部是应力集中的部位,近断端处下部的螺钉颈部和修复体的远端舌侧为形变最大的部位。结论:单端固定式下颌骨修复体在加载时,延伸板的基部和靠近断端的固定螺钉是应力集中的部位,修复体远离固定的一侧是变形最大的部位,提示我们应将延伸板形态设计为尽可能加宽,并应增加下颌骨下缘处的固定,使修复体与下颌骨断端受力更加合理,变形也尽可能缩小。     

单端固定式下颌骨修复体的应力分析

目的：针对包括一侧髁状突的下颌骨缺损,通过有限元应力分析,了解单端固定式下颌骨修复体在功能运动时的受力与变形规律,以期寻求更加合理的修复体的设计和固定方式。方法：建立下颌骨断端和修复体的简易三维模型,模拟咀嚼运动,施加垂直方向载荷,进行有限元法应力分析,计算出该模型各组成部分的应力分布和受力变形。结果：在该模型加载时,延伸板基部和近断端处上部的螺钉颈部是应力集中的部位,近断端处下部的螺钉颈部和修复体的远端舌侧为形变最大的部位。结论：单端固定式下颌骨修复体在加载时,延伸板的基部和靠近断端的固定螺钉是应力集中的部位,修复体远离固定的一侧是变形最大的部位,提示我们应将延伸板形态设计为尽可能加宽,并应增加下颌骨下缘处的固定,使修复体与下颌骨断端受力更加合理,变形也尽可能缩小。     

隆线溞孤雌溞和两性雌溞的蛋白质差异表达

本实验提取隆线溞孤雌溞和两性雌溞的可溶性蛋白进行双向电泳和质谱鉴定,分析隆线溞在两种生殖状态下蛋白质组的差异变化。聚丙烯酰胺凝胶SDS-PAGE结果表明:隆线溞在两种生殖状态下存在明显的蛋白质表达差异,孤雌溞的蛋白条带在分子量约50.6kD、36.2kD、32.1kD和25.7kD处表达量较两性雌溞明显;两性雌的蛋白条带在分子量约87.8kD、67.2kD、53.6kD和35.5kD处表达量较孤雌溞明显,其中35.5kD的蛋白条带为两性雌所特有。同时取两个样品的可溶性蛋白进行双向电泳,每个样品重复四次。双向电泳图谱经银染后利用软件分析可知,隆线孤雌平均可检测到约750个蛋白质点,两性雌溞平均可检测到约720个蛋白质点。同时利用软件对凝胶上的蛋白质点进行半定量分析,发现隆线溞从孤雌生殖转化为两性生殖后有18个蛋白质点呈现显著变化,其中14个点表达量明显下降,4个点表达量显著升高。实验结果具有较好的重复性。取4个表达量显著上升的蛋白质点进行质谱分析,得到两个蛋白质点(16号和17号)的测定结果。其中16号点为一类酸性脱氢酶(2I234),它在动物生长发育的各个阶段大量表达,这类蛋白质在隆线溞生殖转化过程中表达量变化尤为显著。本研究结果表明:隆线溞在孤雌生殖和两性生殖状态下存在明显的蛋白质表达差异。     

B超引导下臂丛神经阻滞麻醉对老年桡骨远端粉碎性骨折患者的麻醉效果分析

摘要 目的：研究B超引导下臂丛神经阻滞麻醉对老年桡骨远端粉碎性骨折患者的麻醉效果。方法：选择2018年12月～2020年6月我院的80例老年桡骨远端粉碎性骨折患者,采用随机数字表法,将患者均分为两组。两组均实施臂丛神经阻滞麻醉,其中对照组使用传统的解剖定位法,观察组使用B超引导法。比较两组的麻醉效果、麻醉用药剂量、阻滞起效时间、麻醉完成时间、镇痛维持时间;不同时间的平均动脉压、心率;且记录两组的脊髓麻痹、气胸、呼吸困难、局麻药物中毒发生率。结果：观察组老年桡骨远端粉碎性骨折病人的麻醉效果优良率（95.00 %）明显高于对照组（77.50 %,P<0.05);观察组的麻醉用药剂量、阻滞起效时间、麻醉完成时间均显著低于对照组,镇痛维持时间长于对照组(P<0.05);两组T2和T3时间点的平均动脉压和心率明显高于T1(P<0.05),且观察组的平均动脉压和心率明显更低(P<0.05);观察组的脊髓麻痹、气胸、呼吸困难、局麻药物中毒发生率明显更低(P<0.05)。结论：B超引导臂丛神经阻滞麻醉能提高老年桡骨远端粉碎性骨折患者的麻醉效果。     

A new methodology to measure load transfer through the forearm using multiple universal force sensors

Previous approaches to measuring forces in the forearm have made the assumption that forces acting in the radius and ulna are uniaxial near the wrist and elbow. To accurately describe forces in the forearm and the forces in the interosseous ligament, we have developed a new methodology to quantitatively determine the 3-D force vectors acting in forearm structures when a compressive load is applied to the hand. A materials testing machine equipped with a six degree-of-freedom universal force–moment sensor (UFS) was employed to apply a uniaxial compressive force to cadaveric forearms gripped at the hand and humerus. Miniature UFSs were implanted into the distal radius and proximal ulna to measure force vectors there. A 3-D digitizing device was used to measure transformations between UFS coordinate systems, utilized for calculating the force vectors in the distal ulna, proximal radius, and the interosseous ligament (IOL). This method was found to be repeatable to within 3 N, and accurate to within 2 N for force magnitudes. Computer models of the forearm, generated from CT scans, were used to visualize the force vectors in 3-D. Application of this methodology to eight forearm specimens showed that the radius carries most of the load at the wrist while force in the IOL relieves load acting in the radius at the mid-forearm. For a 136 N applied hand force, the force in the IOL was 36±21 N. Advantages of this methodology include the determination of 3-D force vectors, especially those in the IOL, as well as computer generated 3-D visualization of results.     

The mechanism of forearm rotation in Varanus exanthematicus

In the sprawling gait of Varanus exanthematicus, the bicondylar distal humerus requires both the radius and ulna to rotate in the same direction. The joints between the radius and radiale and between the ulna and ulnare and pisiform accomodate these specific rotations. A ligament system between radius, ulna, radiale, and ulnare causes the radius and ulna to approximate one another during external rotation of the forearm. This approximation is conveyed distally resulting in a narrowing of the hand during external rotation of radius and ulna or during pronation of the free hand. The significance of these and related linkages is discussed.     

Experimental and finite element analysis of the rat ulnar loading model-correlations between strain and bone formation following fatigue loading

The rat forelimb compression model has been used widely to study bone response to mechanical loading. We used strain gages to assess load sharing between the ulna and radius in the forelimb of adult Fisher rats. We used histology and peripheral quantitative computed tomography (pQCT) to quantify ulnar bone formation 12 days after in vivo fatigue loading. Lastly, we developed a finite element model of the ulna to predict the pattern of surface strains during compression. Our findings indicate that at the mid-shaft the ulna carries 65% of the applied compressive force on the forelimb. We observed large variations in fatigue-induced bone formation over the circumference and length of the ulna. Bone formation was greatest 1-2 mm distal to the mid-shaft. At the mid-shaft, we observed woven bone formation that was greatest medially. Finite element analysis indicated a strain pattern consistent with a compression-bending loading mode, with the greatest strains occurring in compression on the medial surface and lesser tensile strains occurring laterally. A peak strain of -5190 microepsilon (for 13.3N forelimb compression) occurred 1-2 mm distal to the mid-shaft. The pattern of bone formation in the longitudinal direction was highly correlated to the predicted peak compressive axial strains at seven cross-sections (r2 = 0.89, p = 0.014). The in-plane pattern of bone formation was poorly correlated to the predicted magnitude of axial strain at 51 periosteal locations (r2 = 0.21, p < 0.001), because the least bone formation was observed where tensile strains were highest. These findings indicate that the magnitude of bone formation after fatigue loading is greatest in regions of high compressive strain.     

Functional Analysis of the Primate Shoulder

Studies of the shoulder girdle are in most cases restricted to morphological comparisons and rarely aim at elucidating function in a strictly biomechanical sense. To fill this gap, we investigated the basic functional conditions that occur in the shoulder joint and shoulder girdle of primates by means of mechanics. Because most of nonhuman primate locomotion is essentially quadrupedal walking—although on very variable substrates—our analysis started with quadrupedal postures. We identified the mechanical situation at the beginning, middle, and end of the load-bearing stance phase by constructing force parallelograms in the shoulder joint and the scapulo-thoracal connection. The resulting postulates concerning muscle activities are in agreement with electromyographical data in the literature. We determined the magnitude and directions of the internal forces and explored mechanically optimal shapes of proximal humerus, scapula, and clavicula using the Finite Element Method. Next we considered mechanical functions other than quadrupedal walking, such as suspension and brachiation. Quadrupedal walking entails muscle activities and joint forces that require a long scapula, the cranial margin of which has about the same length as the axillary margin. Loading of the hand in positions above the head and suspensory behaviors lead to force flows along the axillary margin and so necessitate a scapula with an extended axillary and a shorter cranial margin. In all cases, the facies glenoidalis is nearly normal to the calculated joint forces. In anterior view, terrestrial monkeys chose a direction of the ground reaction force requiring (moderate) activity of the abductors of the shoulder joint, whereas more arboreal monkeys prefer postures that necessitate activity of the adductors of the forelimb even when walking along branches. The same adducting and retracting muscles are recruited in various forms of suspension. As a mechanical consequence, the scapula is in a more frontal, rather than parasagittal, position on the thorax. In both forms of locomotion—quadrupedal walking and suspension—the compression-resistant clavicula contributes to keeping the shoulder complex distant from the rib cage. Future studies should consider the consequences for thorax shape. The morphological specializations of all Hominoidea match the functional requirements of suspensory behavior. The knowledge of mechanical functions allows an improved interpretation of fossils beyond morphological similarity.     

Normal hip joint contact pressure distribution in single-leg standing--effect of gender and anatomic parameters.

A practical and easy-to-use analysis technique that can study the patient's hip joint contact force/pressure distribution would be useful to assess the effect of abnormal biomechanical conditions and anatomical deformities on joint contact stress for treatment planning purpose. This technique can also help to establish the normative database on hip joint contact pressure distribution in men and women in different age groups. Twelve anatomic parameters and seven biomechanical parameters of the hip joint in a normal population (41 females, 15 males) were calculated. The inter-parameter correlations were investigated. The pressure distribution in the hip joint was calculated using a three-dimensional discrete element analysis (DEA) technique. The 3D contact geometry of the hip joint was estimated from a 2D radiograph by assuming that the femoral head and the acetabular surface were spherical in shape. The head-trochanter ratio (HT), femoral head radius, pelvic height, the joint contact area, the normalized peak contact pressure, abductor force, and the joint contact force were significantly different between men and women. The normalized peak contact pressure was correlated both with acetabular coverage and head-trochanter ratio. Change of abductor force direction within normal variation did not affect the joint peak contact pressure. However, in simulated dysplastic conditions when the CE angle is small or negative, abductor muscle direction becomes very sensitive in joint contact pressure estimation. The models and the results presented can be used as the reference base in computer simulation for preoperative planning in pelvic or femoral osteotomy.     

Multivariate comparison of the forelimb between stump-tailed and rhesus macaques.

Rhesus macaques and stump-tailed macaques are sympatric in western Yunnan (China), coexisting or occupying habitats that show little difference. This paper tests hypotheses based on theoretical expectation from the differing biomechanical demands of terrestrial and arboreal quadrupedalism in stump-tailed macaques and rhesus macaques, respectively. Individuals of these two macaque taxa were markedly separated by the first two principal components and discriminant analyses based on 18 variables of the upper limb. The rhesus macaques appear to be more adapted for arboreal quadruped habits because of elongation of the clavicle and forearm, a larger humeral head and greater midshaft sagittal diameters of the radius and ulna.     

Ulnar Lengthening Using a Half-Ring Sulcated External Fixator for Ulnar Longitudinal Deficiency: A Case Report

Ulnar longitudinal deficiency (ULD) is a rare condition of the upper limbs. Although radius lengthening for radial longitudinal deficiencies (RLD) was found to be successful, no ulnar lengthening for ULD without RLD and hand deformities has been reported. Herein, we present a Bayne type II ULD case report of the ulnar lengthening and gradual reduction of the dislocated radial head in an 11-year-old boy using a half-ring sulcated external fixator. For ulnar lengthening/radial longitudinal traction for radial head reduction, transverse osteotomy in mid ulna was performed and half-ring sulcated external fixator was used for ulnar distraction lengthening. Radial longitudinal traction and stabilization of external fixator were achieved by transverse pins through ulna and radius. Distraction (1 mm/day) began at 5th day and was completed at 95th postoperative day. External fixator was applied for 7 months. Successful ulnar lengthening (81 mm; 62 % gain) was achieved 1-year after the surgery and the range of elbow motion at 2 years was >40°. Forearm rotation and wrist extension/flexion were also preserved with no complaints of pain. We concluded that ulnar distraction lengthening and gradual reduction of radial head could improve appearance of the arm and were of significant benefit to the patient.     

Adhesive dynamics simulation of neutrophil arrest with stochastic activation

The transition from rolling to firm adhesion is a key step in the adhesion cascade that permits a neutrophil to exit the bloodstream and make its way to a site of inflammation. In this work, we construct an integrated model of neutrophil activation and arrest that combines a biomechanical model of neutrophil adhesion and adhesive dynamics, with fully stochastic signal transduction modeling, in the form of kinetic Monte Carlo simulation within the microvilli. We employ molecular binding parameters gleaned from the literature and from simulation of cell-free rolling mediated by selectin molecules. We create a simplified model of lymphocyte function-associated antigen-1 activation that links P-selectin glycoprotein ligand-1 ligation to integrin activation. The model utilizes an energy profile of various integrin activation states drawn from literature data and permits manipulation of signal diffusivity within the microvillus. Our integrated model recreates neutrophil arrest within physiological timescales, and we demonstrate that increasing signal diffusivity within a microvillus accelerates arrest. If the energy barrier between free unactivated and free activated lymphocyte function-associated antigen-1 increases, the period of rolling before arrest increases. We further demonstrate that, within our model, modification of endothelial ligand surface densities can control arrest. In addition, the relative concentrations of signaling molecules control the fractional activation of the overall signaling pathway and the rolling time to arrest. This work presents the first, to our knowledge, fully stochastic model of neutrophil activation, which, though simplified, can recapitulate significant physiological details of neutrophil arrest yet retains the capacity to incorporate additional information regarding mechanisms of neutrophil signal transduction as they are elucidated.     

Estimating maximum and psychophysically acceptable hand forces using a biomechanical weakest link approach

Accurate estimation of occupational performance capability facilitates better job (re-) design by informing workplace parties about the potential mismatches between job demands and the capability of their labour force. However, estimating occupational performance requires consideration of multiple factors that may govern capacity. In this paper, a novel model is described that uses a stochastic algorithm to estimate how variability in underlying biomechanical constraints affects hand force capability. In addition, the model estimates psychophysically acceptable hand force capacity thresholds by applying a biomechanical weakest link approach. Model estimates were tested against experimentally determined maximal and psychophysically determined hand forces in two exertion directions in constrained postures. The model underestimated maximum hand force capacity relative to measured maximum hand force by 30% and 35% during downward pressing and horizontal pulling, respectively. These values are consistent with those observed using previous two-dimensional models. Psychophysically acceptable hand forces were also underestimated by 29% during both pressing and pulling. Since the psychophysical estimates were scaled as a percentage of the estimated maximum capacity, this suggests that the underestimation in both predictions may be corrected by improving estimates of maximum hand force. Psychophysically acceptable forces were observed to be partially governed by demands at the biomechanical weakest link.     

Myosin head mechanical performance under different conformational change mechanisms

The present paper puts forward a mathematical approach to model the conformational changes of the myosin head due to ATP hydrolysis, which determine the head swinging and consequent sliding of the actin filament. Our aim is to provide a simple but effective model simulating myosin head performance to be integrated into the overall model of sarcomere mechanics under development at our Laboratory (J. Biomech. 34 (2001) 1607). We began by exploring myosin head mechanics in recent findings about myosin ultrastructure, morphology and energetics in order to calculate the working stroke distance (WS) and the force transmitted to the actin filament during muscle contraction. Two different working stroke mechanisms were investigated, assuming that the swinging of the myosin head occurs either as a consequence of purely conformational changes (Science 261 (1993a) 58) or by thermally driven motion (ratchet mechanism) followed by conformational changes (Cell 99 (1999) 421). Our results show that force and WS values vary markedly between the two models. The maximum force generated is about 10 pN for the first model and 31 pN for the second model, and the WSs are about 13 and 4 nm, respectively. These results are then discussed and compared with published data. The experimental data used for comparison are scarce and non-homogeneous; hence, the final remarks do not lead to definite conclusions. In any event, relatively speaking, the first model is more coherent with experimental findings.