髌股关节紊乱行关节镜手术治疗对髌股关节生物力学改变的三维有限元分析

目的采用三维有限元方法分析关节镜下行外侧髌骨支持带松解、内侧髌骨支持带紧缩手术前后髌股关节应力分布的改变情况。方法建立髌股关节紊乱患者关节镜手术前后髌股关节三维模型,并计算分析在加载200 N载荷下模型在不同屈膝角度(30°、60°、90°、120°)时的髌股关节最大应力和应力分布。结果关节镜术后模型不同屈膝角度的髌股关节最大应力较术前明显减小;术前髌股关节应力集中在髌股外侧关节面,而术后髌股关节应力得到重新分配。结论关节镜下外侧髌骨支持带松解、内侧髌骨支持带紧缩手术后,髌股关节不同屈膝角度的应力得到改善,为关节镜手术方法可以有效恢复髌股关节内外侧关节面压力平衡提供客观理论依据。对于临床上存在力线异常的早期髌股关节紊乱患者,建议应尽早手术干预。     

Finite element contact analysis of the hip joint

The hip joint plays an important role in the musculoskeletal system; however, current knowledge of the mechanics of the hip joint, especially with regard to the distribution of stress, remains limited. In experimental research, difficulties arise during reproduction of physiological conditions of daily activities and practicable measurement of locations inside the hip joint without violating the physiological environment. On the other hand, numerical approaches, such as finite element analysis, have become useful tools in the field of biomechanics. In finite element contact analysis of the hip joint, due to discretization of contact surfaces, computational instability might occur when the contact nodes move near the edges of the contact elements. In this study, to overcome this problem, a contact smoothing approach was introduced by applying Gregory patches. Contact analysis of the hip joint was then performed for three representative daily activities; i.e., walking, rising up from a chair and knee bending. The effectiveness of the adopted smoothing approach was verified by comparing the results with those obtained experimentally. The distribution and history of contact stress, which have heretofore been scarcely reported, were also obtained and the implications associated with osteoarthritis were discussed.     

脊柱侧凸三维有限元模型的建立及其意义

目的建立胸腰段脊柱侧凸的三维有限元模型。方法螺旋CT扫描脊柱侧凸患者T6椎体上缘至L1椎体下缘,所得图片经Photoshop处理后导入Simpleware软件,采用实体建模方法构建出每一椎体及椎间盘的实体模型,经过逆向工程软件Geomagic光滑、组装后导入有限元分析软件ABAQUS,进行网格划分建成脊柱侧凸的有限元模型。结果所建模型共划分了232315个单元,356830个节点,模型结构完整,单元划分精细,外观逼真,几何相似性好,能精确测量一定载荷下的应力和位移分布。结论本研究所建有限元模型有助于脊柱侧凸的生物力学研究,对于脊柱侧凸的治疗及个性化矫形支具的设计具有指导意义。     

The influence of iliotibial tract thickness on clinical outcomes in women with patellofemoral pain

BackgroundThe assessment of iliotibial tract thickness by ultrasonography may help identify a key, previously unexplored factor that may contribute directly to the homeostasis imbalance of the femoropatellar joint in people with patellofemoral pain (PFP).ObjectivesTo compare the iliotibial tract thickness of people with PFP and asymptomatic people; and to correlate the iliotibial tract thickness with self-reported pain and function of people with PFP.MethodsEighty women, separated into two groups: PFP group (n = 40) and control group consisting of asymptomatic participants (CG; n = 40). The participants answered the Anterior Knee Pain Scale (AKPS) questionnaire, to identify the self-reported knee function; they evaluated the pain in millimeters by the Visual Analog Scale for pain (VAS). For the imaging evaluation, an ultrasound was used, with a linear transducer at the distal portion of the iliotibial tract (coronal plane), with the participants positioned in dorsal decubitus, with 20° of knee flexion. The iliotibial band was visualized in its long axis, and three sequential images were recorded between the lateral femoral condyle and the lateral tibial condyle. The measurements were normalized and correlated.ResultsThe groups had no differences (P > 0.001) between participants for: age/weight/height/IMC. Participants in the PFP group had moderate levels of pain (58 + 2.1 mm), considerable self-reported functional limitation (d = 3.05) and greater iliotibial tract thickness compared with the CG (d = 2.41).ConclusionThe iliotibial tract of women diagnosed with PFP have greater thickness compared with asymptomatic women. There was no association between iliotibial tract thickness and subjective measures of pain and function.     

髂胫束的应用解剖

目的：研究并确定髂胫束的形态和组织结构及体表投影等,为临床用应提供依据。方法：于尸体上观测髂胫束前后区各部的长、宽、厚并做组织切片观察。结果：髂胫束之膜性结构上界约平臀横纹或其上下10mm范围内,前后界分别位于髂前上棘和大转子尖与胫骨外侧髁结节前后缘连线所构成的区域内。左右侧测量值均无明显差异。上述区域以外的阔筋膜均较薄。结论：在髌骨上缘水平以下之髂胫束前后区是阔筋膜最厚处,与胫骨结节附着亦最紧密,该处用于膝交叉韧带等韧性较大的腱性结构损伤的修复材料较理想。     

颅脑有限元模型演化规律及其生物力学研究进展

交通事故中头颈部损伤因其较高的致命性,已成为最严重的损伤类型。有限元模型在创伤性脑损伤生物力学机理研究中得到日益广泛应用。回顾头颈部有限元模型的生物力学研究历史和现状,并阐述车辆碰撞交通事故中人体颅脑典型交通伤演化规律和生物力学研究进展,探索头颈部损伤安全防护的方法,以期为车辆碰撞事故中人体颅脑损伤生物力学研究和相应的汽车安全防护装置研制提供理论依据。     

隐形矫治技术生物力学研究进展

隐形矫治技术是最新的计算机图象处理和辅助设计技术、快速成形技术应用于口腔正畸领域的产物,它的出现顺应了人们追求美观、舒适、健康的现代治疗观,深受广大患者和医生的青睐,现已应用于临床各类错畸形的矫治,但有关该技术的临床疗效、生物学和生物力学机理的研究还不多。本文就隐形矫治技术生物力学研究进展做一综述,为临床上更加合理、科学、有效地应用隐形矫治技术提供理论依据。     

The effect of motion patterns on edge-loading of metal-on-metal hip resurfacing

The occurrence of pseudotumours (soft tissue masses relating to the hip joint) following metal-on-metal hip resurfacing arthroplasty (MoMHRA) has been associated with high serum metal ion levels and consequently higher than normal bearing wear. We investigated the relationship between serum metal ion levels and contact stress on the acetabular component of MoMHRA patients for two functional activities; gait and stair descent. Four subjects with MoMHRA, who had their serum metal ion levels measured, underwent motion analysis followed by CT scanning. Their motion capture data was combined with published hip contact forces and finite element models representing 14% (peak force) and 60% (end of stance) of the gait cycle and 52% (peak force) of stair descent activity were created. The inclination angle of the acetabular component was increased by 10° in 1° intervals and the contact stresses were determined at each interval for each subject.When the inclination angle was altered in such a way as to cause the hip contact force to pass through the edge of the acetabular component edge-loading occurred. Edge-loading increased the contact stress by at least 50%; the maximum increase was 108%. Patients with low serum metal ion levels showed no increase in contact stress at peak force during gait or stair descent. Patients with high serum metal ion levels exhibited edge-loading with an increase to the inclination angle of their acetabular components. The increase in inclination angle that induced edge-loading for these subjects was less than the inter-subject variability in the angle of published hip contact forces. The results of this study suggest that high serum metal ion levels are the result of inclination angle influenced edge-loading but that edge-loading cannot be attributed to inclination angle alone and that an individual's activity patterns can reduce or even override the influence of a steep acetabular component and prevent edge-loading.     

一种股骨头假体个性化设计方法研究

为解决人工髋关节置换手术后假体无菌松动等并发症,适应假体个性化快速设计和制造的需求,对假体设计方法进行研究.采用医用CT技术、计算机辅助设计和有限元计算分析相结合的方法,依据患者股骨髓腔解剖形状和置换要求设计髋关节假体;用有限元软件ANSYS建立股骨的三维有限元模型,并自主开发计算机程序计算得到股骨的材料参数,在股骨有限元模型中实现股骨材料的非均匀及各向异性描述;用计算机仿真植入了定制髋假体的股骨--假体系统后的接触问题;分析对比股骨在术前术后的应力、应变大小及分布,检验假体设计的合理性;定量地确定股骨在手术后所产生的应力遮挡效应的程度,研究结果表明这种假体设计和分析方法更为合理、可靠,为优化设计假体和评估假体植入后的长期稳定性提供了基本方法.     

髂胫束与腓骨长肌筋膜之间的解剖学连续性

目的 为体侧下部筋膜链的存在提供解剖学证据。 方法 选择国人成人尸体下肢标本20例,解剖并观察在腓骨长肌筋膜与髂胫束（ITT）之间筋膜的连续性。对其普遍性的特征作出描述及评估其连续性。若能观测到两者间存在明显的解剖学的连续性,则通过对两者施加一定的拉力来测试该结构对张力的传导能力。 结果 发现了髂胫束与腓骨长肌筋膜之间的间接联系：在所有解剖的下肢标本中,ITT与小腿筋膜连接稳固,而后者与腓侧肌筋膜几乎不可分离。对ITT施加张力会引起小腿筋膜以及腓骨长肌筋膜之间的局部运动。 结论 髂胫束与腓骨长肌筋膜连接稳固,提示其可能在张力传导中起作用。     

髋关节置换假体周围骨折钉棒内固定装置设计、生物力学分析与应用

目的 针对髋关节假体周围骨折固定难、固定不牢靠的问题,设计了一种新型钉棒内固定装置,并对钉棒内固定装置设计、生物力学情况及临床效果进行分析。方法 基于真实人体髋关节及股骨全长CT扫描数据,设计出髋关节置换假体周围骨折钉棒内固定装置,利用Mimics、UG8.0、Abaqus等软件,构建钉棒内固定装置的三维有限元模型并验证了模型的有效性。并将其用于1例Vancouver C型高龄女性患者的手术治疗中。结果 此内固定装置经过三维有限元分析,骨骼受力较小,对骨折固定较稳定;此装置用于一例80岁高龄患者,术后2个月有明显骨痂生长,术后4个月骨折临床愈合,患者弃拐行走,术后效果良好。结论 ①新型内固定装置手术创伤较小,符合微创治疗理念,有利于骨愈合和骨生长,对患者的康复有很重要的作用。②新型内固定装置结构设计上采用股骨远端固定块和Ｕ型环抱装置以及连接块组合式结构,不仅具有结构简单、手术操作方便和减小创伤的特性,而且螺钉的置入位置和方向使得假体的稳定性增强,减小骨骼受力,极大地避免了假体周围再骨折的可能性。     

波峰数目对Z型覆膜支架生物力学性能影响

目的分析Z型覆膜支架波峰数目对覆膜支架生物力学性能,尤其对径向支撑性能及柔顺性影响,为Z型覆膜支架设计以及临床选择提供理论支持。方法通过有限元方法,建立4种不同波峰数目(5、8、10、12)的Z型覆膜支架有限元模型,分别施加径向位移载荷和绕z轴40°转动变量以完成压握和弯折的模拟,并提取支架应力、径向支撑力、覆膜应变、横截面变形程度及弯矩作为评价参数。结果相比波峰数目较多的覆膜支架,压握过程中5波峰覆膜支架具有最大的径向力,提供良好的径向支性能;5波峰覆膜支架在弯折模拟中产生了68 N·mm的最小力矩及67.5%的最小弯折横截面变形程度,并且在弯曲过程中覆膜的拉伸应变较小。结论 Z型覆膜支架波峰数目对覆膜支架生物力学性能的影响显著。波峰数目相对较少的Z型覆膜支架在径向支撑性能及弯曲力矩、横截面形变程度等柔顺性评价方面表现出优势,有利于覆膜支架在血管内的固定贴合,对减少血栓和内漏等并发症具有积极意义。研究结果可以指导Z型覆膜支架优化设计及手术最优选择。     

两种术式髓核摘除对腰椎生物力学影响的有限元分析

目的评价两种术式髓核摘除对腰椎节段稳定性和纤维环应力的影响。方法在L4-5节段三维有限元模型上分别模拟骨性椎板开窗髓核摘除和椎板间隙开窗髓核摘除,施加不同类型载荷,观察节段间旋转角度和纤维环最大应力的改变。结果骨性椎板开窗髓核摘除后,腰椎节段在前屈和后伸载荷下旋转角度分别增加31%和28%,纤维环最大应力分别增加16%和6%;椎板间隙开窗髓核摘除后,腰椎节段在前屈和后伸载荷下旋转角度分别增加33%和39%,纤维环最大应力分别增加17%和0.2%。两种术式髓核摘除后,纤维环的应力分布均没有发生改变。结论和椎板间隙开窗相比,骨性椎板开窗髓核摘除能更好地保持腰椎的后伸稳定性,但后伸时纤维环承受的应力明显增大。     

三维有限元法分析膝关节内侧副韧带的生物力学功能

目的通过建立膝关节三维有限元模型,研究内侧副韧带维持膝关节稳定性的作用。方法膝关节韧带用金属丝标记,止点采用钻孔标记,行CT扫描,应用Mimics、Geomagic和Ansys软件对数据进行三维重建,建立膝关节三维有限元模型,在膝关节5个不同的屈曲角度下模拟膝关节的前后平移、外翻和内外旋运动。结果膝关节在屈曲0°、30°6、0°、90°和120°时,MCL的应力为4.84、3.55、2.17、1.26和0 MPa;膝关节在5个角度下向前平移时,MCL的应力为7.22、5.78、4.07、2.84和1.4 MPa;向后平移时,应力为8.14、6.454、.19、2.92和1.6 MPa;内旋时,应力为6.815、.233、.292、.25和0.97 MPa;外旋时,应力为6.285、.003、.342、.21和0.82 MPa;外翻时,应力为11.00、9.55、7.25、5.94和3.11 MPa。结论通过建立膝关节三维有限元模型模拟膝关节前后移、外翻和内外旋各动作,可以有效地分析膝关节内侧副韧带的生物力学功能。     

全腰椎三维有限元模型的建立及其有效性验证

目的建立全腰椎及骶椎的有限元模型,为分析L4～5之间纤维环易破裂的病理提供可靠的模型。方法利用健康成人椎骨的CT影像,采用Mimics医学图像处理软件和Geomagic逆向工程软件建立L1～S1椎骨和椎间盘三维模型,再导入有限元软件Hypermesh中划分网格,并附加腰椎相关韧带,赋予材料属性,建立边界条件,构建腰椎加骶椎有限元模型;模拟腰椎受轴向压力、前弯、侧弯和后伸4种载荷下的生物力学反应。结果模型在受到10 N.m载荷作用分别发生前屈、侧弯和后伸运动下的整体刚度分别为0.61、0.7和0.75 N.m/(°),与实验结果较为吻合;轴向施加力和弯矩时L4～5之间的纤维环应变较大;纤维环在各种载荷下均出现较明显的应力集中。结论 L4～5之间纤维环局部应力集中和应变较大是导致其易破裂的原因之一;所建立的L1～S1椎体三维有限元模型符合脊柱生物力学特性,可用于脊柱生物力学的进一步研究。     

颞下颌关节三维有限元建模相关因素分析

颞下颌关节的生物力学研究对理解颞下颌关节病的发生、发展具有重要意义。有限元方法可以分析颞下颌关节各组织受到外力或者发生形变后组织内部的应力和应变情况,但其复杂而且细致的解剖结构导致构建有限元模型的研究总是耗时、昂贵和不可重复。为寻求一种更为快捷、精确的下颌骨三维有限元模型建立方法,提高颞下颌关节有限元建模精度,针对模型与实体几何相似性、生物力学环境仿真模拟等相关因素进行综述。     

不同载荷作用下头部生物力学响应仿真分析

目的建立符合解剖结构的人颅骨三维有限元模型,研究多种载荷作用下头部生物力学响应。方法通过建立具有解剖结构的高精度头部有限元模型,颅骨采用能模拟骨折的弹塑性材料本构模型,结合已发表的正面冲击颅内压实验、动态颅骨骨折实验、头部跌落实验结果,仿真再现实验过程中头部受冲击载荷作用下的生物力学响应、颅骨骨折及头部不同速度下的跌落响应。结果前碰撞表现出冲击与对冲侧正-负颅内压分布,相近载荷下枕骨变形比前额、顶骨严重,跌落中速度越快损伤越大。结论建立精确解剖结构的头部有限元模型可以较好模拟头部在冲击、跌落等载荷下的生物力学响应。通过量化接触力、颅内压力等参数来评价头部损伤风险,为防护系统的设计提供科学依据。     

2~5掌指关节屈伸活动中关节面应力分布的有限元分析

目的　建立掌指关节三维有限元模型,分析掌指关节屈伸活动中掌指关节面应力分布情况。 方法　健康男性志愿者1名,对其右手掌指关节分别于0°、30°、60°、90°屈曲位进行CT扫描,利用扫描数据建立掌指关节三维有限元模型;于4个角度沿指骨径向分别施以10、20、30、40、50 N荷载,观察掌指关节应力分布,并对结果进行分析。 结果　4组不同弯曲角度的掌指关节网格模型节点数量、单元数量基本相同,每组模型约40070个节点,178903个四面体单元。相同载荷作用下,弯曲的角度越大,各掌指关节面的应力越大。在实现0°、30°、60°、90°屈曲过程中,2~5掌指关节掌骨头应力峰值变化范围分别为0.20~2.46、0.22~1.58、0.22~1.69、0.22~2.25 Mpa。 结论　掌指关节屈伸过程中,弯曲的角度越大,掌指关节面的接触应力越大,其应力分布范围亦增大。     

一种生物力学腋拐的研究与设计

目的针对以往腋拐存在的问题,设计一款结构简单、外形美观、科学合理的实用性腋拐。方法从人体生物力学、人机工程学、工业设计等方面出发,利用模块设计、柔性设计的方法对腋拐进行创新设计。结果经力学分析、有限元分析、样机质量检验、初步临床试用,验证了设计的可行性和临床适用性。结论本次新型腋拐的研究和设计具有极大的临床意义,其可有效减小使用者手腕和腋窝的受力,进而降低二次伤害的发生机率。同时,也可以为类似的拐杖设计提供参考。     

3-D finite element analysis of the influence of synovial condition in sacroiliac joint on the load transmission in human pelvic system

The anterior part of the sacroiliac joint (SIJ) is a synovial joint, with little gliding and rotary movement between the contact surfaces of SIJ during locomotion. Due to its complex structure, especially when considering the surrounding ligaments, it is difficult to construct an accurate three-dimensional (3-D) finite element model for the human pelvis. Most of the pelvic models in the previous studies were simplified with either SIJ fusing together or without the sacral bone. However, the influence of those simplifications on the load transmission in human pelvis has not been studied, so the reliability of those studies remains unclear. In this study, two 3-D pelvic models were constructed: an SIJ fusing model and an SIJ contacting model. In the SIJ fusing model, the SIJ interfaces were fused together. In the SIJ contacting model, the SIJ interfaces were just in contact with each other without fusion. Compared with the SIJ contacting model, the SIJ fusing model have smaller movements in the SIJ. The stress distribution area in the SIJ fusing model on sacroiliac cartilages was also different. Those differences contributed to the decline of tensile force in the SIJ surrounding ligaments and the re-distribution of stress in the pelvic bones. In addition, the SIJ fusing model was far less sensitive to the increase in modulus of the sacroiliac cartilages, and decrease in stiffness of the ligaments surrounding the SIJ. The presence of synovia in the SIJ had greater influence on the load transmission in the human pelvic system. Therefore, the effect of the presence of synovia should not be neglected when the biomechanical behavior of human pelvis is being studied, especially for those studies related to clinical applications.