The effects of an articulated ankle-foot orthosis with resistance-adjustable joints on lower limb joint kinematics and kinetics during gait in individuals post-stroke

BackgroundResistance is a key mechanical property of an ankle-foot orthosis that affects gait in individuals post-stroke. Triple Action® joints allow independent adjustment of plantarflexion resistance and dorsiflexion resistance of an ankle-foot orthosis. Therefore, the aim of this study was to investigate the effects of incremental changes in dorsiflexion and plantarflexion resistance of an articulated ankle-foot orthosis with the Triple Action joints on lower limb joint kinematics and kinetics in individuals post-stroke during gait.MethodsGait analysis was performed on 10 individuals who were post-stroke under eight resistance settings (four plantarflexion and four dorsiflexion resistances) using the articulated ankle-foot orthosis. Kinematic and kinetic data of the lower limb joints were recorded while walking using a three-dimensional Vicon motion capture system and a Bertec split-belt instrumented treadmill.FindingsRepeated measures analysis of variance revealed that adjustment of plantarflexion resistance had significant main effects on the ankle (P < 0.001) and knee (P < 0.05) angles at initial contact, while dorsiflexion resistance had significant (P < 0.01) main effects on the peak dorsiflexion angle in stance. Plantarflexion and dorsiflexion resistance adjustments appeared to affect the peak knee flexor moment in stance, but no significant main effects were revealed (P = 0.10). Adjustment of plantarflexion resistance also demonstrated significant (P < 0.05) main effects in the peak ankle positive power in stance.InterpretationThis study demonstrated that the adjustments of resistance in the ankle-foot orthosis with the Triple Action joints influenced ankle and knee kinematics in individuals post-stroke. Further work is necessary to investigate the long-term effects of the articulated ankle-foot orthoses on their gait.     

Effect of heel pressure pad attached to ankle-foot orthosis on the energy conversion efficiency in post-stroke hemiplegic gait

[Purpose] This study aimed to analyze the effect of heel pads in ankle-foot orthoses on dynamic motion aspects of gait in stroke patients from the viewpoint of energy conversion efficiency. [Subjects] Fourteen chronic stroke patients who were ambulatory and had lower extremity motor function categorized as Brunnstrom stage IV participated in the study. [Methods] A three-dimensional motion analysis system was used to assess the effect of heel pad intervention on dynamic motion gait parameters using a single-system A-B-A design. [Results] The results showed that a heel pad attached to the ankle-foot orthosis caused significant retention of the center-of-pressure at the heel during the heel rocker function and significant increase in the dorsiflexion moment and the height of the center of gravity. [Conclusion] The present study showed that a heel pad attached to the calcaneal region of an ankle-foot orthosis caused slight retention of the center-of-pressure at the heel during the heel rocker function along with center of gravity elevation in the stance phase and improved the energy conversion efficiency, especially on the non-paretic side.Key words: Heel pad, Three-dimensional motion analysis, Hemiplegic gait     

佩戴踝足矫形器对痉挛型脑性瘫痪儿童足底压力步态的作用

背景:由于设计及方法的差异,佩戴蹀足矫形器对脑性瘫痪(脑瘫)儿童步行时运动学、运动力学、能耗等各方面的影响尚未取得统一的结果.目的:观察佩戴踝足矫形器对痉挛型脑瘫患儿足底压力步态特征的影响.方法:采用足底压力式步态分析系统对21例具有独立步行能力的痉挛型脑瘫儿童进行步态分析.分别记录同一天内、同一时间段、同一种身体状态下不佩戴踝足矫形器及佩戴踝足矫形器步行时每例脑瘫患儿足底压力式步态分析数据,包括时间参数、运动学参数以及各参数的绝对对称性指标,并进行对比.记录双足的足底压力重心偏移轨迹作为步行能力的定性直观观察指标,对比佩戴支具前后的足底压力重心偏移轨迹图并做对照描述.结果与结论:与未佩戴踝足矫形器相比,佩戴踝足矫形器使痉挛型脑瘫患儿步态周期时间缩短,步频增加(P<0.01).佩戴踝足矫形器步行时脑瘫儿童单足支撑期、单侧支撑期、单足摆动期、步态周期时间的绝对对称性指标值均较未佩戴矫形器时显著减少(P<0.05).痉挛型脑瘫儿童步行时双足的足底压力重心偏移轨迹表现出无序的特性,不能形成左右对称的蝴蝶状轨迹图.佩戴踝足矫形器后,足底压力中心偏移轨迹比未佩戴时有序,尖足步态患儿佩戴踝足矫形器后患足的足底压力偏移轨迹起始点后移.结果提示痉挛型脑瘫儿童佩戴踝足矫形器后步态周期时间缩短,步频增加,步态对称性改善,总体步行能力得到提高.足底压力式步态分析系统能以客观精确的数据和直观的图表表达,是评定脑瘫儿童步行能力的一种新型测试手段.     

Co-contraction patterns of trans-tibial amputee ankle and knee musculature during gait

ABSTRACT: BACKGROUND: Myoelectric control of upper extremity powered prostheses has been used clinically for many years, however this approach has not been fully developed for lower extremity prosthetic devices. With the advent of powered lower extremity prosthetic components, the potential role of myoelectric control systems is of increasing importance. An understanding of muscle activation patterns and their relationship to functional ambulation is a vital step in the future development of myoelectric control. Unusual knee muscle co-contractions have been reported in both limbs of trans-tibial amputees. It is currently unknown what differences exist in co-contraction between trans-tibial amputees and controls. This study compares the activation and co-contraction patterns of the ankle and knee musculature of trans-tibial amputees (intact and residual limbs), and able-bodied control subjects during three speeds of gait. It was hypothesized that residual limbs would have greater ankle muscle co-contraction than intact and able-bodied control limbs and that knee muscle co-contraction would be different among all limbs. Lastly it was hypothesized that the extent of muscle co-contraction would increase with walking speed. METHODS: Nine unilateral traumatic trans-tibial amputees and five matched controls participated. Surface electromyography recorded activation from the Tibialis Anterior, Medial Gastrocnemius, Vastus Lateralis and Biceps Femoris of the residual, intact and control limbs. A series of filters were applied to the signal to obtain a linear envelope of the activation patterns. A co-contraction area (ratio of the integrated agonist and antagonist activity) was calculated during specific phases of gait. RESULTS: Co-contraction of the ankle muscles was greater in the residual limb than in the intact and control limbs during all phases of gait. Knee muscle co-contraction was greater in the residual limb than in the control limb during all phases of gait. CONCLUSION: Co-contractions may represent a limb stiffening strategy to enhance stability during phases of initial foot-contact and single limb support. These strategies may be functionally necessary for amputee gait; however, the presence of co-contractions could confound future development of myoelectric controls and should thus be accounted for.     

The influence of ankle-foot orthosis stiffness on walking performance in individuals with lower-limb impairments

Background

Passive-dynamic ankle-foot orthoses utilize stiffness to improve gait performance through elastic energy storage and return. However, the influence of ankle-foot orthosis stiffness on gait performance has not been systematically investigated, largely due to the difficulty of manufacturing devices with precisely controlled stiffness levels. Additive manufacturing techniques such as selective laser sintering have been used to successfully manufacture ankle-foot orthoses with controlled stiffness levels. The purpose of this study was to use passive-dynamic ankle-foot orthoses manufactured with selective laser sintering to identify the influence of orthosis stiffness on walking performance in patients with lower-limb neuromuscular and musculoskeletal impairments.

Methods

Thirteen subjects with unilateral impairments were enrolled in this study. For each subject, one passive-dynamic ankle-foot orthosis with stiffness equivalent to the subject's clinically prescribed carbon fiber orthosis, one 20% more compliant and one 20% more stiff, were manufactured using selective laser sintering. Three-dimensional kinematic and kinetic data and electromyographic data were collected from each subject while they walked overground with each orthosis at their self-selected velocity and a controlled velocity.

Findings

As the orthosis stiffness decreased, ankle range of motion and medial gastrocnemius activity increased while the knee became more extended throughout stance. Minimal changes in other kinematic, kinetic and electromyographic quantities were observed.

Interpretation

Subjects effectively compensated for changes in ankle-foot orthosis stiffness with altered gastrocnemius activity, and the stiffness levels analyzed in this study had a minimal effect on overall walking performance.     

Immediate effects of an individually designed functional ankle-foot orthosis on stance and gait in hemiparetic patients

OBJECTIVE: To evaluate the immediate effects of individually designed functional in-shoe ankle-foot orthoses (AFO) made of soft and hard cast on balance, standing, and gait parameters in hemiparetic patients. DESIGN: Crossover design with randomized order of the intervention. SETTING: A rehabilitation centre for adults with neurological disorders. SUBJECTS: Twenty-eight patients with hemiparesis due to stroke or traumatic brain injury. MEASURES: Postural sway, standing and gait parameters based on ground reaction forces in two conditions: Patients were randomly assigned to varying sequences of wearing AFO in footwear or wearing footwear alone. RESULTS: AFO significantly improved weight-bearing on the affected leg (affected/ unaffected side symmetry: 2.25 +/- 1.5 with AFO versus 3.4 +/- 2.5 without AFO, P<0.05) and postural sway in stance (12.5 mm +/- 5.2 with AFO versus 15.7 mm +/- 6.7 without AFO, P < 0.05), double stance duration (21.1 +/-14.4% of gait cycle with AFO versus 25.9 +/- 21.6% of gait cycle without AFO, P < 0.05), and symmetry ratios of gait parameters such as stance duration (2.0 +/- 1.5 s with AFO versus 3.3 +/- 3.6 s without AFO, P < 0.05) and deceleration forces (1.6 +/- 0.5 with AFO versus 1.9 +/- 0.6 without AFO, P < 0.05) during gait. No significant differences were observed in all other symmetry ratios of gait parameters. CONCLUSION: An individually designed functional in-shoe AFO can improve stance and gait parameters, even in a single use, in patients with hemiparesis.     

The effect of hinged ankle-foot orthosis on gait and energy expenditure in spastic hemiplegic cerebral palsy

Purpose.?To assess the effectiveness of a hinged ankle-foot orthoses on gait impairments and energy expenditure in children with hemiplegic cerebral palsy (CP) whom orthoses were indicated to control equines.

Method.?Eleven children (seven males, four females) who had a diagnosis of hemiplegic cerebral palsy were included in the study. Each child underwent gait analysis and energy consumption studies with and without ankle-foot orthosis (AFO). The AFOs were all custom-made for the individual child and had plantarflexion stop at 0° with no dorsoflexion stop. The Vicon 512 Motion analysis system was used for gait analysis. Walking energy expenditure measurements were done with breath by breath method using an open-circuit indirect calorimeter (Vmax 29c, Sensormedics, USA). All tests were carried out on the same day with enough resting period.

Results.?AFO application, as compared with the barefoot condition improved walking speed, stride length and single support time. Double support time was decreased significantly with AFOs and no change in cadance. Ankle dorsiflexion at initial contact, midstance and midswing showed significiant increase. Knee flexion at initial contact was decreased and no significant change in maximum knee extension at stance and maximum knee flexion at swing was obtained. The oxygen consumption was significantly reduced during AFO walking.

Conclusion.?The hinged AFO is useful in controlling dynamic equinus deformity and reducing the energy expenditure of gait in children with hemiplegic spastic cerebral palsy.     

The effect of hinged ankle-foot orthosis on gait and energy expenditure in spastic hemiplegic cerebral palsy

Purpose. To assess the effectiveness of a hinged ankle-foot orthoses on gait impairments and energy expenditure in children with hemiplegic cerebral palsy (CP) whom orthoses were indicated to control equines.

Method. Eleven children (seven males, four females) who had a diagnosis of hemiplegic cerebral palsy were included in the study. Each child underwent gait analysis and energy consumption studies with and without ankle-foot orthosis (AFO). The AFOs were all custom-made for the individual child and had plantarflexion stop at 0° with no dorsoflexion stop. The Vicon 512 Motion analysis system was used for gait analysis. Walking energy expenditure measurements were done with breath by breath method using an open-circuit indirect calorimeter (Vmax 29c, Sensormedics, USA). All tests were carried out on the same day with enough resting period.

Results. AFO application, as compared with the barefoot condition improved walking speed, stride length and single support time. Double support time was decreased significantly with AFOs and no change in cadance. Ankle dorsiflexion at initial contact, midstance and midswing showed significiant increase. Knee flexion at initial contact was decreased and no significant change in maximum knee extension at stance and maximum knee flexion at swing was obtained. The oxygen consumption was significantly reduced during AFO walking.

Conclusion. The hinged AFO is useful in controlling dynamic equinus deformity and reducing the energy expenditure of gait in children with hemiplegic spastic cerebral palsy.     

Peak knee adduction moment during gait in anterior cruciate ligament reconstructed females

Background

Recent work has shown that anterior cruciate ligament reconstructed patients exhibit an increased peak knee adduction moment during walking gait compared to healthy controls. An increased peak knee adduction moment has been suggested to be a potential mechanism of degeneration for knee osteoarthritis. The few studies in this area have not considered an exclusively female anterior cruciate ligament reconstructed group. This study tested the hypothesis that female anterior cruciate ligament-reconstructed patients would have higher peak knee adduction moments than controls.

Methods

Peak knee adduction moment during walking was compared between a group of anterior cruciate ligament reconstructed females and a group of female activity matched controls over ten 15 m walking trials in a laboratory at a self-selected pace.

Findings

Peak knee adduction moment was lower for the anterior cruciate ligament reconstructed group (N = 17, M = 0.31 Nm/kg·m, SD = 0.08) than for the control group (N = 17, M = 0.41 Nm/kg·m, SD = 0.12; t(32) = 2.483, p = 0.010, one-tailed, eta squared effect size = 0.16).

Interpretation

A group of female anterior cruciate ligament reconstructed subjects did not exhibit a gait characteristic which has been suggested to be associated with knee osteoarthritis development and has been shown to be present in male and mixed sex anterior cruciate ligament reconstructed populations previously.     

Role of ankle mobility in foot rollover during gait in individuals with diabetic neuropathy

Background

The purpose of this study was to investigate the ankle range of motion during neuropathic gait and its influence on plantar pressure distribution in two phases during stance: at heel–strike and at push-off.

Methods

Thirty-one adults participated in this study (control group, n = 16; diabetic neuropathic group, n = 15). Dynamic ankle range of motion (electrogoniometer) and plantar pressures (PEDAR-X system) were acquired synchronously during walking. Plantar pressures were evaluated at rearfoot, midfoot and forefoot during the two phases of stance. General linear model repeated measures analysis of variance was applied to investigate relationships between groups, areas and stance phases.

Findings

Diabetic neuropathy patients walked using a smaller ankle range of motion in stance phase and smaller ankle flexion at heel–strike (P = 0.0005). Peak pressure and pressure–time integral values were higher in the diabetic group in the midfoot at push-off phase when compared to heel–strike phase. On the other hand, the control group showed similar values of peak pressure in midfoot during both stance phases.

Interpretation

The ankle mobility reduction observed could be associated to altered plantar pressure distribution observed in neuropathic subjects. Results demonstrated that midfoot and forefoot play a different role in subjects with neuropathy by receiving higher loads at push-off phase that are probably due to smaller ankle flexion at stance phase. This may explain the higher loads in anterior areas of the foot observed in diabetic neuropathy subjects and confirm an inadequate foot rollover associated to the smaller ankle range of motion at the heel–strike phase.     

踝足矫形器材料学特点及其临床应用

目的:用于脑性瘫痪患儿的传统金属踝足矫形器具有制作工序多,制作条件高、制作后不易修整和较笨重等缺点,越来越多的研究者将现代高分子材料用于踝足矫形器的制作.目的:分析几种踝足矫形器的材料学特点,探讨各种材料的踝足矫形器在治疗脑性瘫痪患儿膝反张中的应用情况.方法:作者应用计算机检索 CNKI 数据库(www.cnki.net/index.htm),在标题和摘要中以:"膝反张,脑性瘫痪,踝足矫形器"为检索词进行检索.选择文章内容能及时准确地报道脑性瘫痪患儿应用踝足矫形器矫治的研究进展和运用情况,共纳入19篇文献.结果与结论:踝足矫形器的制作材料包括高分子树脂材料、聚乙烯材料、聚丙烯材料、低温热塑板材料、半成品高分子纤维等.脑性瘫痪患儿佩戴以上材料制作的踝足矫形器可以增强踝关节稳定性,减轻肌张力,提高行走的速度及步幅,改善步态功能.     

肩部矫形器在脑卒中后异常步态康复中的研究进展

脑卒中后偏瘫通常对人体运动能力和稳定性产生不利影响,患者常因肌无力、双侧肢体肌张力失衡、感觉异常、关节和姿势控制不良等出现肩关节半脱位、异常步态。肩部矫形器常用于脑卒中偏瘫的早期预防或治疗肩关节半脱位,但目前仍存在争议。为探索肩部矫形器除预防和治疗肩关节半脱位外的作用,为肩部矫形器的选择及佩戴提供理论依据,该文阐述了肩部矫形器可能改善脑卒中后异常步态的机制,分类对比不同类型肩部矫形器对脑卒中后异常步态的矫正效果。     

踝足矫形器数学模型、应用处方及其早期应用对脑卒中患者偏瘫步态影响的趋势分析

随着多体系统动力学理论和计算机技术的发展,矫形器的计算机辅助设计和制造(CAD/CAM)技术已经日趋成熟,利用这项新技术可建立人体和矫形器的数学力学模型,通过模拟计算来确定矫形器处方、预测疗效和康复效果.踝足矫形器(AFO)早期应用对于脑卒中患者脑功能恢复、偏瘫步态恢复以及对于纠正异常步态起重要作用,在康复临床矫形器处方中,建立相应的数学模型,推测足踝功能变化和脑卒中后脑功能恢复的作用和机制,这对偏瘫步态的分析、矫形器的设计和患者步态的恢复等方面都会产生积极影响.     

踝足矫形器在脑性瘫痪治疗中的应用及其改进

脑性瘫痪主要影响患儿的行走功能，出现异常的运动步态，矫形器可以通过限制异常运动，保持关节的稳定性，加强肢体的承重能力，通过三点力学原理矫正肢体的畸形或防止畸形加重，改善患儿坐、站和步行的能力，促进运动发育。作为治疗的一部分，矫形器的使用愈来愈受到重视，其中踝足矫形器的应用较为广泛。但踝足矫形器也存在限制机体肌肉活动，使躯干或肢体长时间受压等问题，为了解决上述问题，科研工作者从矫形器的结构设计对原有矫形器进行改进，并研制出了符合个体要求的、多功能的、舒适的踝足矫形器。同时越来越多的研究者将现代高分子材料应用于矫形器的制作，高分子材料固化前质软如泥，适型性好而易于成型，固化后具有很好的坚固度、韧性、透气性能、质地坚韧、不影响X射线检查，高分子材料制作的矫形器具有轻质、弹性好、强度大、透气性好、舒适、轻便美观等优点。     

Effect of treadmill walking with ankle stretching orthosis on ankle flexibility and gait

[Purpose] The purpose of this study was to evaluate the kinematics of the ankle in thelunge to estabilish effectiveness of an ankle stretching orthosis (ASO) on the ankledorsiflexion range of motion (ROM) of individuals with limited dorsiflexion ROM. [Subjectsand Methods] Forty ankles with decreased dorsiflexion ROM of 20 participants wereevaluated in this study. After wearing the ASO, participants walked on a treadmill for 15minutes. Participants walked on the treadmill at a self-selected comfortable speed. Ankledorsiflexion ROM, maximum dorsiflexion ROM before heel-off, and time to heel-off duringthe stance phase of gait were measured before and after 15 minutes of treadmill walkingwith the ASO. The differences in all variables between before and after treadmill walkingwith ASO were analyzed using the paired t-test. [Results] Ankle active and passive ROM,and dorsiflexion ROM during lunge increased significantly after treadmill walking withASO. Treadmill walking with the ASO significantly increased the angle of maximaldorsiflexion before heel-off and time to heel-off during the stance phase. [Conclusion]The results of this study show that treadmill walking with the ASO effectively improvedankle flexibility and restored the normal gait pattern of the ankle joint by increasingdorsiflexion ROM, maximal angle of dorsiflexion, and time to heel-off in the stancephase.     

介绍一种小儿头皮针固定法

目前,截瘫病人的康复治疗在国内外已取得了一定的进展,除常规的运动疗法、作业疗法外,现代生物力学、生物工程学的发展,特别是矫形器的发展越来越受到人们的重视[1]。我科于2004年2月—2006年10月对18例不同原因造成的下肢截瘫病人,运用膝踝足链条矫形器辅助走路,起到了很好的效果,达到了预期的治疗目标。1临床资料本组18例,男11例,女7例,年龄8岁～62岁,平均年龄35岁,胸腰椎损伤性截瘫7例,脑卒中偏瘫5例,脑外伤后遗症4例,颈椎损伤2例,均经X线、CT或MRI确诊。均采用塑料结构的膝踝足带链条矫形器矫形,因其轻便,弹性好,并能很好地控制压力…