Chevron截骨术对外翻足关节接触特征影响的生物力学研究

目的 探究Chevron截骨术截骨远端外侧位移距离对外翻足关节接触特征的影响,为临床上选择合适的位移距离提供参考依据。方法 测量踝关节中立位状态下正常足、外翻足及外翻足Chevron截骨术截骨远端分别向外侧位移2.0、4.0、6.0 mm后前足、中足和后足各关节接触力、峰值压强和接触面积,并对结果进行分析。结果 与正常足相比,外翻足第1跖楔关节（t=-3.33, P=0.02）、跟骰关节（t=-2.74, P=0.03）和距下关节（后关节面）（t=-2.89, P=0.03）的接触力显著增高;外翻足距舟关节（t=-2.73, P=0.03）与跟骰关节（t=-2.74, P=0.03）的峰值压强显著增高;行Chevron截骨术后,随着截骨远端向外侧位移距离的增加,外翻足第1跖楔关节和跟骰关节的接触力逐渐减小;外翻足距舟关节和跟骰关节的峰值压强逐渐减小。结论 中度外翻足行Chevron截骨术后,当第1跖骨截骨远端向外侧位移6 mm时能有效恢复部分关节间力的分布,且能缓解部分关节局部应力集中现象。     

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。     

跖腱膜对第1跖趾关节活动的影响

目的　认识跖腱膜对维持第1跖趾关节稳定性的作用,探讨早期　僵硬手术治疗的可行性。 方法　采用6例新鲜尸体足标本,固定于自制生物力学加载支架,用逐级定量的方法对第1跖趾关节进行力学加载,测量跖腱膜离断前后第1跖趾关节背屈活动范围的变化。 结果　跖腱膜离断前第1跖趾关节背屈为（68.34±3.05）°,跖腱膜离断后背屈为（78.50±3.77）°,较离断前增加了（10.16±2.10）°（t=11.83,P<0.05）。 结论　跖腱膜对维持第1跖趾关节稳定有重要作用,损伤后要尽可能修复;某些足部疾病的治疗如需离断跖腱膜,尽量做部分离断;跖腱膜切开术可能是治疗早期拇僵硬可以选择的一种手术方法。     

踝关节融合术后后足关节生物力学分析

目的 探讨踝关节融合术后后足关节的生物力学特性。方法 利用健康成年男性志愿者右踝关节CT图像，构建踝关节融合前的三维有限元模型，在此基础上模拟踝关节融合术后骨性融合状态，采用中立、外旋、内旋、背伸和跖屈的5种载荷工况分别对融合前、后模型组进行有限元分析，评估踝关节融合前后的整体刚度变化、距下关节和距舟关节的接触力学特性变化。结果 踝关节发生骨性融合后，整体结构刚度较融合前模型显著增高；除中立位工况以外，融合后的距下关节的接触面积均有所减少，距舟关节接触面积则有所增加；而融合后的距下和距舟关节的接触应力在各工况下总体呈降低趋势。结论 踝关节骨性融合术后相邻关节的接触特性改变可能是足部整体结构刚度提高后承载模式发生变化的结果，其与相邻后足关节退行性改变之间的关联尚有待进一步研究证实。     

跑者足部形态与足趾及跖趾关节屈肌力量的相关性

目的 探究坐姿及站姿下跑者足部形态与足趾屈曲力量和跖趾关节屈肌力量的相关性.方法 选取26名男性跑者,采用数显游标卡尺、跖趾关节屈肌力量测试仪、屈曲力量计测量足长、截脚长、足宽、足舟骨高度、50％足长处足背高度、跖趾关节屈肌力量、第1和其余四趾屈曲力量.使用偏相关分析足部形态与足部肌力的相关性.结果 校正年龄与身体质量...     

距舟关节的三维运动度及其临床意义

目的探讨距舟关节的三维运动范围及其在足运动中的作用.方法采用12例新鲜青壮年小腿足标本,牢固地固定胫骨,标记距骨和足舟骨,分别对足前部加载不同的负荷,使前足处于特定的不同运动状态,用三维数字化仪测量标记点的三维坐标值,计算距舟关节的相对三维运动值,分析距舟关节和前足的运动范围及两者间的关系.结果前足相对胫骨的单一跖屈-背屈运动范围为84.1°±6.2°,内翻-外翻为61.8°±5.1°,内收-外展为49.3°±5.0°,在上述前足的单纯运动过程中,距舟关节的上述三维运动范围依次为18.3°±4.9°、32.3°±4.7°和28.37°±4.0°,分别占前足相应运动范围的21.8%、52.2%、和57.5%.结论距舟关节具有较大的三维运动范围,在前足的三维运动和足板的扭曲变形运动中发挥重要作用,并对踝关节的跖屈-背屈运动具有一定的代偿作用.     

基于有限元模型分析不同蹬冰角度足踝部应力分布差异

目的 模拟仿真不同蹬冰角度足踝部的应力,通过优化分析得到合理的蹬冰角度与足踝部应力的定量关系。 方法 建立冰球鞋-足踝耦合有限元模型,三维拍摄获取冰球运动员的运动学参数进行模型验证与约束,计算对比 分析不同角度蹬冰动作的足踝部应力,构建多目标优化函数模型。 结果 在相同蹬冰角度下,胫腓骨应力最大,距 下关节应力次之,第 1 跖趾关节应力较小,足底筋膜应力最小。 随着蹬冰角度的减小,足踝部应力单调递增,胫腓 骨和足底筋膜应力变化幅度大,距下关节和第 1 跖趾关节应力变化幅度较小。 结论 在冰球运动启动阶段蹬冰过 程中,蹬冰角度与足踝不同部位应力呈反比例关系。 最佳蹬冰角度取决于对滑冰速度的期待值,如果给定速度与 应力承受之间的偏好系数,可通过优化方法计算出最优蹬冰角度。     

第1跖趾关节相关生物力学研究进展

第1跖趾关节既参与前足横弓的构成,又是足内侧纵弓的重要组成部分,在维持足弓牛物力学稳定方面起着举足轻重的作用,其稳定性的破坏会引起前足生物力学的改变从而严苇影响足部负重和行走功能的有效行使,临床上(足)外翻、前跖痛等许多足部疾病的发生发展均与第1跖趾火节稳定性的破坏有关,本文主要就第1跖趾关节相关牛物力学的研究进展作一综述.     

有限元建模分析牵开成形治疗踝关节骨性关节炎的生物力学响应

背景：目前踝关节骨性关节炎的手术方式包括关节置换和关节融合,但2种方式均存在一定问题,因此保踝治疗成为踝关节骨性关节炎初期治疗的首选方式。牵开成形是一种重要的保踝治疗术式,有利于缓解踝关节疼痛和改善功能,有助于关节软骨的自我修复,但现在仍缺乏确切的生物力学证据。目的：通过有限元建模探究踝关节牵开成形治疗早中期无明显力线改变的踝关节骨性关节炎的力学因素,为临床治疗提供力学证据。方法：将1名27岁志愿者足踝CT扫描数据DICOM文件导入有限元软件中,进行三维重建及曲面拟合,再进行网格划分,建立含有骨骼、韧带、肌腱和软骨的精细足踝有限元模型,对比踝骨关节炎组、外固定架组分别在中立0°、跖屈20°、背屈20°3种不同工况下的胫距关节面应力、距骨应力及距骨应变的生物力学响应。结果与结论：（1）经过有限元仿真计算发现,从踝关节整体受力来说,两组模型在中立位0°时最小,从中立位逐渐跖屈或背屈时,随着踝关节活动发生变化,应力值也逐渐增加,且在同等屈曲的条件下,背屈要比跖屈的整体应力增幅明显;（2）从胫距关节的应力峰值来说,踝骨关节炎组的胫距关节面应力峰值较正常组增幅明显,外固定架组的胫距关节面应力峰值...     

足韧带的解剖学研究及其临床意义

目的:研究足韧带的解剖学特点,探讨其临床意义。方法:30侧成人足标本解剖观测各韧带起至、走行和比邻,分析其作用。结果:距舟背侧韧带分为内、外两束。楔舟背侧韧带分为内、中、外、斜4束。足横弓和纵弓交汇处为足底最凹点,足底长短韧带、腓骨长肌腱、胫骨后肌腱为"外三角",楔舟足底韧带、楔骰足底韧带、跟舟足底韧带为"内三角",维系该凹点。跟舟足底韧带承托距骨头部,是将踝压力分向第1跖骨头和足跟的首要韧带。各楔骨、楔骰骨间韧矢状面上都位于关节前侧,不规则形,质地强韧,维系足横弓。结论:足部韧带分为足背、足底和骨间3个系统,结构复杂,其功能及其在创伤外科中的意义有待深入研究。     

A Population of Patient-Specific Adult Acquired Flatfoot Deformity Models Before and After Surgery

Following IRB approval, a cohort of 3-D rigid-body computational models was created from submillimeter MRIs of clinically diagnosed Adult Acquired Flatfoot Deformity patients and employed to investigate postoperative foot/ankle function and surgical effect during single-leg stance. Models were constrained through physiologic joint contact, passive soft-tissue tension, active muscle force, full body weight, and without idealized joints. Models were validated against patient-matched controls using clinically utilized radiographic angle and distance measures and plantar force distributions in the medial forefoot, lateral forefoot, and hindfoot. Each model further predicted changes in strain for the spring ligament, deltoid ligament, and plantar fascia, as well as joint contact loads for three midfoot joints, the talonavicular, navicular-1st cuneiform, and calcaneocuboid. Radiographic agreement ranged across measures, with average absolute deviations of <5° and <4 mm indicating generally good agreement. Postoperative plantar force loading in patients and models was reduced for the medial forefoot and hindfoot concomitant with increases in the lateral forefoot. Model predicted reductions in medial soft-tissue strain and increases in lateral joint contact load were consistent with in vitro observations and elucidate the biomechanical mechanisms of repair. Thus, validated rigid-body models offer promise for the investigation of foot/ankle kinematics and biomechanical behaviors that are difficult to measure in vivo.     

The innervation of the joints of the foot

The nerve supply of the ankle joint and of the joints of the foot was studied in dissections of fetal and adult feet and in serial sections of fetal feet stained with silver. The ankle joint was supplied by the tibial, sural, deep peroneal, and saphenous nerves, and by the accessory deep peroneal nerve when present. The tarsal joints were supplied on their plantar aspects by the medial or lateral plantar nerves, and on their dorsal aspects chiefly by the deep peroneal nerve. The joint between the lateral and intermediate cuneiform received branches from the intermediate dorsal cutaneous nerve also. The lateral dorsal cutaneous nerve and the accessory deep peroneal nerve when present provided additional branches to the subtalar and calcaneocuboid joints. The tarsometatarsal joints were supplied on their plantar aspects by the medial or lateral plantar nerves. Most of them were supplied on their dorsal aspects by the deep peroneal nerve, but the cuboid-metatarsal joints received their supply from the intermediate dorsal cutaneous nerve. The intermetatarsal joints had a similar but sparser supply. The joint between the fourth and fifth metatarsal received branches from the intermediate dorsal cutaneous nerve. The plantar digital nerves provided the main supply to the metatarsophalangeal joints. The dorsal aspect of the first metatarsophalangeal joint was supplied by the deep peroneal and the medial dorsal cutaneous nerves, of the second metatarsophalangeal joint by the deep peroneal nerve, and of the fourth and fifth metatarsophalangeal joints by the lateral dorsal cutaneous nerve. The interphalangeal joints did not receive articular branches from the dorsal digital nerves, except in the case of the interphalangeal joint of the big toe, which was supplied by the deep peroneal and the medial dorsal cutaneous nerves.     

Subject-Specific Axes of Rotation Based on Talar Morphology Do Not Improve Predictions of Tibiotalar and Subtalar Joint Kinematics

Use of subject-specific axes of rotation may improve predictions generated by kinematic models, especially for joints with complex anatomy, such as the tibiotalar and subtalar joints of the ankle. The objective of this study was twofold. First, we compared the axes of rotation between generic and subject-specific ankle models for ten control subjects. Second, we quantified the accuracy of generic and subject-specific models for predicting tibiotalar and subtalar joint motion during level walking using inverse kinematics. Here, tibiotalar and subtalar joint kinematics measured in vivo by dual-fluoroscopy served as the reference standard. The generic model was based on a cadaver study, while the subject-specific models were derived from each subject’s talus reconstructed from computed tomography images. The subject-specific and generic axes of rotation were significantly different. The average angle between the modeled axes was 12.9° ± 4.3° and 24.4° ± 5.9° at the tibiotalar and subtalar joints, respectively. However, predictions from both models did not agree well with dynamic dual-fluoroscopy data, where errors ranged from 1.0° to 8.9° and 0.6° to 7.6° for the generic and subject-specific models, respectively. Our results suggest that methods that rely on talar morphology to define subject-specific axes may be inadequate for accurately predicting tibiotalar and subtalar joint kinematics.     

踝关节与距下关节矢状断层解剖学

目的：为踝、距下关节病变及损伤的诊断、修复和重建提供矢状断层解剖学基础。方法：用成年男尸右足标本5例，置冰柜冻硬后，每例切制4个踝及后足部矢状断层标本。结果：胫距关节矢状径最长为31．9mm，距骨滑车与胫骨关节软骨厚各为2．5mm与2．4mm，胫距关节间隙为2．6mm，内侧韧带厚为3．1mm；前、后距下关节软骨厚分别为1．5mm、1．2mm与1．7mm、1．4mm，关节间隙为0．8mm与1．4mm，后距下关节矢状径最长为18．9mm，距跟骨间韧带长8．6mm，矢状径为2．6mm。结论：本文结果为临床踝、距下关节疾患的诊治及关节镜技术提供了解剖学资料。     

Biomechanics of first ray hypermobility: An investigation on joint force during walking using finite element analysis

Hypermobility of the first ray is suggested to contribute to hallux valgus. The investigation of first ray hypermobility focused on the mobility and range of motion that based on manual examination. The load transfer mechanism of the first ray is important to understand the development and pathomechanism of hallux valgus. In this study, we investigated the immediate effect of the joint hypermobility on the metatarsocuneiform and metatarsophalangeal joint loading through a reduction of the stiffness of the foot ligaments.A three-dimensional foot model was constructed from a female aged 28 via MRI. All foot and ankle bones, including two sesamoids and the encapsulated bulk tissue were modeled as 3D solid parts, linking with ligaments of shell elements and muscles connectors. The stance phase of walking was simulated by the boundary and loading conditions obtained from gait analysis of the same subject.Compared with the normal foot, the hypermobile foot had higher resultant metatarsocuneiform and metatarsophalangeal joint forces. The increases accounted for 18.6% and 3.9% body weight. There was also an abrupt change of metatarsocuneiform joint force in the medial–lateral direction. The predicted results represented possible risk of joint problems and metatarsus primus varus.     

An investigation of the dynamic relationship between navicular drop and first metatarsophalangeal joint dorsal excursion

The modern human foot is a complex biomechanical structure that must act both as a shock absorber and as a propulsive strut during the stance phase of gait. Understanding the ways in which foot segments interact can illuminate the mechanics of foot function in healthy and pathological humans. It has been proposed that increased values of medial longitudinal arch deformation can limit metatarsophalangeal joint excursion via tension in the plantar aponeurosis. However, this model has not been tested directly in a dynamic setting. In this study, we tested the hypothesis that during the stance phase, subtalar pronation (stretching of the plantar aponeurosis and subsequent lowering of the medial longitudinal arch) will negatively affect the amount of first metatarsophalangeal joint excursion occurring at push‐off. Vertical descent of the navicular (a proxy for subtalar pronation) and first metatarsophalangeal joint dorsal excursion were measured during steady locomotion over a flat substrate on a novel sample consisting of asymptomatic adult males and females, many of whom are habitually unshod. Least‐squares regression analyses indicated that, contrary to the hypothesis, navicular drop did not explain a significant amount of variation in first metatarsophalangeal joint dorsal excursion. These results suggest that, in an asymptomatic subject, the plantar aponeurosis and the associated foot bones can function effectively within the normal range of subtalar pronation that takes place during walking gait. From a clinical standpoint, this study highlights the need for investigating the in vivo kinematic relationship between subtalar pronation and metatarsophalangeal joint dorsiflexion in symptomatic populations, and also the need to explore other factors that may affect the kinematics of asymptomatic feet.     

Biomechanical study of tarsometatarsal joint fusion using finite element analysis

Complications of surgeries in foot and ankle bring patients with severe sufferings. Sufficient understanding of the internal biomechanical information such as stress distribution, contact pressure, and deformation is critical to estimate the effectiveness of surgical treatments and avoid complications. Foot and ankle is an intricate and synergetic system, and localized intervention may alter the functions to the adjacent components. The aim of this study was to estimate biomechanical effects of the TMT joint fusion using comprehensive finite element (FE) analysis. A foot and ankle model consists of 28 bones, 72 ligaments, and plantar fascia with soft tissues embracing all the segments. Kinematic information and ground reaction force during gait were obtained from motion analysis. Three gait instants namely the first peak, second peak and mid-stance were simulated in a normal foot and a foot with TMT joint fusion. It was found that contact pressure on plantar foot increased by 0.42%, 19% and 37%, respectively after TMT fusion compared with normal foot walking. Navico-cuneiform and fifth meta-cuboid joints sustained 27% and 40% increase in contact pressure at second peak, implying potential risk of joint problems such as arthritis. Von Mises stress in the second metatarsal bone increased by 22% at midstance, making it susceptible to stress fracture. This study provides biomechanical information for understanding the possible consequences of TMT joint fusion.