足弓第2与第5跖列的肌骨系有限元模型及其临床意义

目的：建立足部内侧纵弓第2跖列与外侧纵弓第5跖列的肌骨系统有限元模型,为研究跖骨应力性骨折与相关足痛症提供生物力学工具。方法：采用中国虚拟人“女性1号”CT图像和MRI图像;应用非线性有限元方法进行生物力学分析。结果：构建了包含皮质骨、松质骨、软骨、韧带、足底腱膜、肌腱、固有肌、脂肪垫、骨髓腔与骨髓窦等10种组织的第2、第5跖列的有限元模型。足弓直立时,最大von Mises应力／应变位于第2、第5跖骨骨干与基底。各种足底软组织中,足底腱膜承担着最大张拉应力,其次为足底长韧带,足底固有肌张拉应力最小。结论：有限元预测的应力应变为研究跖骨应力性骨折,足底腱膜炎引起的慢性跟骨痛,以及足弓塌陷的发生机制提供了生物力学依据。     

足底的血管构筑与跖弓皮瓣、肌皮瓣对足跟缺损的修复

目的：用跖弓皮瓣、肌皮瓣足跟缺损、提供足底三套血管网分布特点的解剖学依据。方法：在２０例福尔马林、４例红色乳胶灌注的成人尸体标本上、观察足底内、外侧动脉的起始、行径、分支及其吻合情况。结果：足底共有三套血管网供血：１．足底内侧动脉的内、外侧支在嘴展肌深面分支分布,形成足底内侧血管网。２．足底内侧动脉外侧支与足底外侧动脉的分支在足底腱膜与趾短屈肌之间吻合形成足底浅弓。３．足底内侧动脉的内侧支与足底外     

不同站姿足底压力分布与足弓结构特征的相关性

目的 探讨不同站姿时足底压力分布与足弓结构特征之间的相关性。 方法 对 13 名健康成年男性进行足底压力测试,并进行足部 CT 扫描和足骨模型重构,建立足弓数字化表征。 在此基础上,分析足底压力测量指标与足弓特征测量参数之间的相关性。 结果 前足峰值压力(forefoot peak pressure, FPP)在 0°站姿时与内外侧纵弓高度、内外侧纵弓指数和体质量正相关,与内外侧纵弓角负相关;在 30°站姿时与内外侧纵弓长度、内侧纵弓高度、足底三角形面积和体质量正相关;在 60°站姿时与内外侧纵弓高度和内侧纵弓指数正相关,与内侧纵弓角负相关。 中 足峰值压力(midfoot peak pressure, MPP)在 0°站姿时与内外侧纵弓长度和足底三角形面积正相关;在 30°站姿时与内外侧纵弓长度、内外侧纵弓角和足底三角形面积正相关,与内外侧纵弓指数负相关;在 60°站姿时与内外侧纵弓长度、足底三角形面积和体质量正相关。 后足峰值压力(rearfoot peak pressure, RPP)在 0°站姿时与内外侧纵弓高度、内外侧纵弓指数和体质量正相关,与内外侧纵弓角负相关;在 30°和 60°站姿时仅与体质量正相关,与足弓特征参数无关。 结论 不同站姿时的足底压力分布与足弓特征存在不同相关性。 研究结果可为临床诊断、治疗和预防因不同站姿引起的足部病理提供理论基础。     

足横弓的维持及生物力学

足弓包括内外侧纵弓和中前足的横弓。对内外侧纵弓的结构、生物力学及临床意义已有较深入的研究,而对横弓的探讨相对较少。足横弓的组成与生物力学目前认识不尽相同,成为争论的热点。本文主要就足横弓近年来的研究进展作一综述。     

足部三维有限元建模方法及其生物力学应用

目的探讨建立足部三维有限元模型的方法,应用模型模拟分析研究鞋垫设计参数,不同软组织刚度和受力情况下对足部的生物力学影响。方法建立基于解剖结构,包括软组织,韧带和腱膜,考虑材料的非线性和关节接触的足部三维有限元模型。有限元模型的可靠性利用模拟足踝关节在不同病理、手术和鞋垫矫治情况下的生物力学反应来验证。结果有限元分析结果表明,定制型鞋垫的形状比鞋垫材料的刚度对减少足底最大压力有更重要影响。软组织刚度的增加引起足底接触面积的减小,从而会导致足底跖骨区最大压力增加。部分和完全松解足底腱膜都会降低足弓高度,并增加足底韧带的张力和增加中足和跖骨的应力。体重增加和跟腱拉力增加都将成倍足底筋膜的拉力。结论所建足部有限元模型能预测足底压力分布和足内部骨骼软组织应力、应变情况,可以成为设计鞋垫和研究足部各种临床状况提供有力的分析工具。     

足底浅弓的解剖学研究

通过对动脉灌注,研究了６０侧不同年龄尸体的足底浅弓,此弓虽细小,在足底浅层中恒定存在,可分完整型和不完整型,完整型由足底内侧动脉浅支和足底外侧动脉组成,占７０％,不完整型由足度内侧动脉浅支与第３或第４跖足底动脉的分支吻合而成,占３０％,由足底内,外侧动脉发４地动静脉链伴行趾底总神经,分别与各跖足底动脉连接,对人类足底浅弓的残遗进行了讨论。     

足底腱膜的解剖

目的观察足底腱膜的形态结构,为临床应用提供相关的解剖学资料。方法解剖50只10%甲醛固定的足,观察足底腱膜浅层的形态结构;测量足底腱膜中间部(跖腱膜)止于跖骨头处内、外侧纤维束的厚度与长度;跖腱膜中间部的厚度。结果足底腱膜浅层的纤维结构主要参与前外侧部足底脂肪垫的构成,并形成与足底皮纹相似的螺旋纤维板状结构,足跟部足底腱膜浅层的纤维结构较为稀疏。中间部的厚度为(2.168±0.1139)mm;跖腱膜于第1跖骨头处内、外侧纤维束的厚度分别为(1.33±0.08)mm、(1.46±0.07)mm,明显大于止于2~5跖骨头处的内、外侧纤维厚度,P0.05;第5跖骨头处的内、外侧纤维厚度分别为(0.29±0.02)mm、(0.37±0.04)mm,明显小于1~4跖骨头处的内、外侧纤维厚度,P0.05。结论足底腱膜浅层主要参与足前外侧脂肪垫的构成,足底腱膜深层对维持足部纵弓的稳定起着非常重要的作用,在足部受力时有效地避免足前部趾足底总神经、趾足底总血管受压。     

轻度与重度骨关节炎膝关节的生物力学行为比较

目的 对比研究轻度与重度膝骨关节炎(knee osteoarthritis, KOA)膝关节的生物力学行为,阐述KOA进展的生物力学机制。方法 分别构建同一患者左侧轻度KOA(KL分级Ⅰ级)与右侧重度KOA(KL分级Ⅳ级)膝关节有限元模型。在材料属性、边界条件、载荷等设定相同的情况下进行有限元分析,比较轻度与重度KOA膝关节半月板、股骨软骨、胫骨软骨的接触面积、接触压及von Mises应力的变化特征。结果 重度KOA膝关节总接触面积和外侧室接触面积大于轻度KOA膝关节,而内侧间室接触面积小于轻度KOA膝关节。重度KOA膝关节半月板、股骨软骨和胫骨软骨上的接触压及von Mises应力峰值均大于轻度KOA膝关节;双膝关节外侧半月板上接触压及von Mises应力峰值均大于内侧半月板,双膝关节股骨软骨与胫骨软骨内侧间室接触压及von Mises应力峰值均大于外侧间室。结论 重度KOA膝关节应力分布不同于轻度KOA,接触面积、接触压和von Mises应力峰值的变化与半月板脱位、软骨缺损等因素相关,生物力学行为和解剖结构的改变促进了KOA进展。     

内侧柱稳定手术治疗Ⅱ期成人胫后肌腱功能不全性平足的三维有限元生物力学分析

文题释义：平足内侧柱稳定手术：是指通过实施融合固定手术即融合舟楔关节或者跖楔关节,或者两者均融合来稳定足的第一跖列,恢复内侧纵弓的高度,纠正前足的旋前。 背景：平足症是足踝外科的常见病,其中Ⅱ期成人获得性平足在临床上最多见,此期的治疗最为关键。然而Ⅱ期平足内侧柱存在着不稳定,这也是造成足弓塌陷的重要原因。内侧柱稳定手术可以相当程度地纠正畸形,但是目前尚缺乏详细的生物力学实验来全面判断内侧柱稳定后对于全足带来的影响。 目的：探讨单纯内侧柱稳定手术对Ⅱ期成人获得性平足足部生物力学的影响。 方法：首先建立Ⅱa期及Ⅱb期成人获得性平足三维有限元模型,通过Geomagic软件、Solidwork软件及Abaqus软件模拟内侧柱稳定手术(舟楔关节融合､跖楔关节融合､两者均融合),将术前和术后模型模拟单倍体质量负重,比较其足底、内外侧柱骨块、内侧韧带的最大应力值,并通过测量相关参数来进行综合对比。 结果与结论：①单纯内侧柱稳定术后模拟负重时足底应力最大值均出现在第一跖骨头下方,其中Ⅱa期模型行内侧柱稳定后足底应力最大值明显增加,Ⅱb期模型内侧柱稳定后足底应力变化不明显;②内侧柱融合后相应关节的应力有所减轻,但对于第一跖列的其他关节应力反而增加了;③内侧柱融合后对于内侧韧带及足底筋膜的应力均没有减轻作用;④结果表明,单纯内侧柱稳定手术并不能降低Ⅱ期成人获得性平足内侧柱的压力,它仅可以作为联合使用的手术来稳定过度活动的关节以及纠正前足旋后畸形。 ORCID: 0000-0002-8230-1151(刘付胜华) 中国组织工程研究杂志出版内容重点：人工关节;骨植入物;脊柱;骨折;内固定;数字化骨科;组织工程     

外侧楔形鞋垫对足踝生物力学影响的有限元分析

目的 探究外侧楔形鞋垫对足踝内部组织(包括足骨、关节和韧带)的生物力学影响。 方法 建立并验证足踝-鞋垫-地面三维有限元模型,探究步态 3 个关键瞬间赤足模型和鞋垫干预模型的足底压力分布、关节接触压力、跖骨及主要韧带的应力。 结果 5°外侧楔形鞋垫模型足底峰值压力比赤足模型减小 65. 8% 。 鞋垫干预使楔舟关节处峰值接触压力减小;距下关节处峰值接触压力和第 4、5 跖骨处峰值应力增大。 结论 本研究量化评估了外侧楔形鞋垫对足踝各部分的生物力学影响,提出了可适当减小外侧楔形鞋垫第 4、5 跖骨处倾斜角度的设计建议。     

Clinical significance of musculoskeletal finite element model of the second and the fifth foot ray with metatarsal cavities and calcaneal sinus

Aim

The aim of this study was to establish musculoskeletal finite element (FE) model of the second and the fifth foot ray accounting for metatarsal cavities and calcaneal sinus. The model was then used to predict the effects of metatarsal cavities and calcaneal sinus on internal stresses/strains of plantar longitudinal arches.

Materials and methods

The geometry of foot bones and soft tissues were constructed by CT and MRI images of Virtual Chinese Human “female No. 1”. Two types of nonlinear FE models of sagittal foot rays were developed with or without metatarsal cavities and calcaneal sinus using ANSYS © software package. The sagittal trabecular architecture of metatarsals and calcaneus were obtained by cutting, defatting and bleaching fresh foot specimen of a cadaver.

Results

The model proposed was able to describe the isostatic stress flows in sagittal planes of plantar longitudinal arches. The size of metatarsal cavity or calcaneal sinus could affect stress/strain distributions on metatarsals and calcaneus, but had almost no effects on stress/strain of other foot bones and plantar soft tissues. During balance standing, the maximum von Mises stresses were predicted at the shaft and the basis of metatarsals, while the maximum strains of bony regions were found around metatarsal cavities. Among plantar soft tissues, relative high tensions were burdened by plantar fascia, followed by long plantar ligament. The minimum tensions occurred in plantar intrinsic muscles.

Conclusions

The study shows that the tension/compression stress flows are geometrically similar with the tension/compression trabecular architectures in sagittal sections of metatarsal and calcaneus. The FE predictions of stress/strain concentration on metatarsals and fascia are useful in enhancing biomechanical knowledge on metatarsal stress fractures and plantar fasciitis.

     

Mechanical Analysis of Foot Plantar Fascia in Normal Walking Condition

Foot plantar fascia is a kind of important tissue in stabilizing the longitudinal arch of human foot. Direct measurement to monitoring the mechanical situation of plantar fascia at human locomotion is very difficult. The purpose of this study is to construct a three-dimensional finite element model of the foot to calculate the internal stress/strain value of plantar fascia during different stages of the gait. The simulated stress distribution of plantar fascia was the lowest at heel-strike,which concentrated on the medial side of calcaneal tubercle. The peak stress of plantar fascia was appeared at push-off,and the value was more than 5 times of the heel-strike position. Current FE model was able to explore the plantar fascia tension trend at the main subphases of the foot. More detailed fascia models and intrinsic muscle forces could be developed in the further study.     

韧带和跖腱膜在足部有限元分析中的力学作用

目前通过建立足部三维有限元系统模型进行足部生物力学仿真已经逐渐被应用,而在大多数足部三维有限元模型的静态分析中,韧带和跖腱膜等软组织是通过直接连接骨骼上相应的附着点形成的索单元来模拟,而关节软骨把相邻的骨骼直接固连在一起.这种用关节软骨固连的方式代替真实的骨骼间的滑动摩擦,增强了骨骼间的结构强度,可能会造成原本由韧带等起到维持骨骼间相互作用却完全由关节软骨代替,即在有限元模型中,可能韧带等组织对仿真不起力学作用.本文的研究目的是在双足站立、静态载荷,关节采用固连方式时,分析足部三维有限元模型中有无韧带和跖腱膜对足部各种组织应力分布以及组织结构形态变化等的影响.     

Using an Optimization Approach to Design an Insole for Lowering Plantar Fascia Stress—A Finite Element Study

Plantar heel pain is a commonly encountered orthopedic problem and is most often caused by plantar fasciitis. In recent years, different shapes of insole have been used to treat plantar fasciitis. However, little research has been focused on the junction stress between the plantar fascia and the calcaneus when wearing different shapes of insole. Therefore, this study aimed to employ a finite element (FE) method to investigate the relationship between different shapes of insole and the junction stress, and accordingly design an optimal insole to lower fascia stress. A detailed 3D foot FE model was created using ANSYS 9.0 software. The FE model calculation was compared to the Pedar device measurements to validate the FE model. After the FE model validation, this study conducted parametric analysis of six different insoles and used optimization analysis to determine the optimal insole which minimized the junction stress between plantar fascia and calcaneus. This FE analysis found that the plantar fascia stress and peak pressure when using the optimal insole were lower by 14% and 38.9%, respectively, than those when using the flat insole. In addition, the stress variation in plantar fascia was associated with the different shapes of insole.     

Plantar fascia anatomy and its relationship with Achilles tendon and paratenon

Although the plantar fascia (PF) has been studied quite well from a biomechanical viewpoint, its microscopic properties have been overlooked: nothing is known about its content of elastic fibers, the features of the extracellular matrix or the extent of innervation. From a functional and clinical standpoint, the PF is often correlated with the triceps surae muscle, but the anatomical grounds for this link are not clear. The aim of this work was to focus on the PF macroscopic and microscopic properties and study how Achilles tendon diseases might affect it. Twelve feet from unembalmed human cadavers were dissected to isolate the PF. Specimens from each PF were tested with various histological and immunohistochemical stains. In a second stage, 52 magnetic resonance images (MRI) obtained from patients complaining of aspecific ankle or foot pain were analyzed, dividing the cases into two groups based on the presence or absence of signs of degeneration and/or inflammation of the Achilles tendon. The thickness of PF and paratenon was assessed in the two groups and statistical analyses were conducted. The PF is a tissue firmly joined to plantar muscles and skin. Analyzing its possible connections to the sural structures showed that this fascia is more closely connected to the paratenon of Achilles tendon than to the Achilles tendon, through the periosteum of the heel. The PF extended medially and laterally, continuing into the deep fasciae enveloping the abductor hallucis and abductor digiti minimi muscles, respectively. The PF was rich in hyaluronan, probably produced by fibroblastic‐like cells described as ‘fasciacytes’. Nerve endings and Pacini and Ruffini corpuscles were present, particularly in the medial and lateral portions, and on the surface of the muscles, suggesting a role for the PF in the proprioception of foot. In the radiological study, 27 of the 52 MRI showed signs of Achilles tendon inflammation and/or degeneration, and the PF was 3.43 ± 0.48 mm thick (99%CI and SD = 0.95), as opposed to 2.09 ± 0.24 mm (99%CI, SD = 0.47) in the patients in which the MRI revealed no Achilles tendon diseases; this difference in thickness of 1.29 ± 0.57 mm (99%CI) was statistically significant (P < 0.001). In the group of 27/52 patients with tendinopathies, the PF was more than 4.5 mm thick in 5, i.e. they exceeded the threshold for a diagnosis of plantar fasciitis. None of the other 25/52 paitents had a PF more than 4 mm thick. There was a statistically significant correlation between the thicknesses of the PF and the paratenon. These findings suggest that the plantar fascia has a role not only in supporting the longitudinal arch of the foot, but also in its proprioception and peripheral motor coordination. Its relationship with the paratenon of the Achilles tendon is consistent with the idea of triceps surae structures being involved in the PF pathology, so their rehabilitation can be considered appropriate. Finally, the high concentration of hyaluronan in the PF points to the feasibility of using hyaluronan injections in the fascia to treat plantar fasciitis.     

The role of fasciae in Civinini–Morton's syndrome

This study evaluates the pathogenetic role of the perineural connective tissue and foot fasciae in Civinini–Morton's neuroma. Eleven feet (seven male, four female; mean age: 70.9 years) were dissected to analyse the anatomy of inter‐metatarsal space, particularly the dorsal and plantar fasciae and metatarsal transverse ligament (DMTL). The macrosections were prepared for microscopic analysis. Ten Civinini–Morton neuromas obtained from surgery were also analysed. Magnetic resonance images (MRIs) from 40 patients and 29 controls were compared. Dissections showed that the width of the inter‐metatarsal space is established by two fibrous structures: the dorsal foot fascia and the DMTL, which, together, connect the metatarsal bones and resist their splaying. Interosseous muscles spread out into the dorsal fascia of the foot, defining its basal tension. The common digital plantar nerve (CDPN) is encased in concentric layers of fibrous and loose connective tissue, continuous with the vascular sheath and deep foot fascia. Outside this sheath, fibroelastic septa, from DMTL to plantar fascia, and little fat lobules are present, further protecting the nerve against compressive stress. The MRI study revealed high inter‐individual variability in the forefoot structures, although only the thickness of the dorsal fascia represented a statistically significant difference between cases and controls. It was hypothesized that alterations in foot support and altered biomechanics act on the interosseous muscles, increasing the stiffness of the dorsal fascia, particularly at the points where these muscles are inserted. Chronic rigidity of this fascia increases the stiffness of the inter‐metatarsal space, leading to entrapment of the CDPN.