Change in the Mechanical Energy of the Body Center of Mass in Hemiplegic Gait after Continuous Use of a Plantar Flexion Resistive Ankle-foot Orthosis

[Purpose] The aim of this study was to investigate the changes in mechanical energy due to continuous use of a plantar flexion resistive ankle-foot orthosis (AFO) of subjects with chronic hemiplegia. [Subjects and Methods] The subjects were 5 hemiplegic patients using AFOs without a plantar flexion resistive function in their daily lives. We analyzed the gait of the subjects using a 3D motion capture system under three conditions: patients’ use of their own AFOs; after being fitted with a plantar flexion resistive AFO; and after continuous use of the device. The gait efficiency was determined by calculating the mutual exchange of kinetic and potential energy of the center of mass. [Results] An increased exchange rate of the kinetic and potential energy was found for all subjects. A larger increase of energy exchange was shown on the non-paralyzed side, and after continuous use of the plantar flexion resistive AFO. [Conclusion] We found that continuous use of a plantar flexion resistive AFO increased the rate of mutual exchange between kinetic energy and potential energy. The change in the rate was closely related to the role of the non-paretic side, showing that the subjects needed a certain amount of time to adapt to the plantar flexion resistive AFO.Key words: Hemiplegic gait, Plantar flexion resistive ankle-foot orthosis, Mechanical energy of the body center of mass     

Effect of Ankle-Foot Orthosis Alignment and Foot-Plate Length on the Gait of Adults With Poststroke Hemiplegia

Fatone S, Gard SA, Malas BS. Effect of ankle-foot orthosis alignment and foot-plate length on the gait of adults with poststroke hemiplegia.

Objective

To investigate the effect of ankle-foot orthosis (AFO) alignment and foot-plate length on sagittal plane knee kinematics and kinetics during gait in adults with poststroke hemiplegia.

Design

Repeated measures, quasi-experimental study.

Setting

Motion analysis laboratory.

Participants

Volunteer sample of adults with poststroke hemiplegia (n=16) and able-bodied adults (n=12) of similar age.

Interventions

Subjects with hemiplegia were measured walking with standardized footwear in 4 conditions: (1) no AFO (shoes only); (2) articulated AFO with 90° plantar flexion stop and full-length foot-plate-conventionally aligned AFO (CAFO); (3) the same AFO realigned with the tibia vertical in the shoe-heel-height compensated AFO (HHCAFO); and (4) the same AFO (tibia vertical) with ¾ length foot-plate-¾ AFO. Gait of able-bodied control subjects was measured on a single occasion to provide a normal reference.

Main Outcome Measures

Sagittal plane ankle and knee kinematics and kinetics.

Results

In adults with hemiplegia, walking speed was unaffected by the different conditions (P=.095). Compared with the no AFO condition, all AFOs decreased plantar flexion at initial contact and mid-swing (P<.001) and changed the peak knee moment in early stance from flexor to extensor (P<.000). Both AFOs with full-length foot-plates significantly increased the peak stance phase plantar flexor moment compared with no AFO and resulted in a peak knee extensor moment in early stance that was significantly greater than control subjects, whereas the AFO with three-quarter length foot-plate resulted in ankle dorsiflexion during stance and swing that was significantly less than control subjects.

Conclusions

These findings suggest that when an articulated AFO is to be used, a full-length foot-plate in conjunction with a plantar flexion stop may be considered to improve early stance knee moments for people with poststroke hemiplegia.     

Contribution of ankle-foot orthosis moment in regulating ankle and knee motions during gait in individuals post-stroke

BackgroundAnkle-foot orthosis moment resisting plantarflexion has systematic effects on ankle and knee joint motion in individuals post-stroke. However, it is not known how much ankle-foot orthosis moment is generated to regulate their motion. The aim of this study was to quantify the contribution of an articulated ankle-foot orthosis moment to regulate ankle and knee joint motion during gait in individuals post-stroke.MethodsGait data were collected from 10 individuals post-stroke using a Bertec split-belt instrumented treadmill and a Vicon 3-dimensional motion analysis system. Each participant wore an articulated ankle-foot orthosis whose moment resisting plantarflexion was adjustable at four levels. Ankle-foot orthosis moment while walking was calculated under the four levels based on angle-moment relationship of the ankle-foot orthosis around the ankle joint measured by bench testing. The ankle-foot orthosis moment and the joint angular position (ankle and knee) relationship in a gait cycle was plotted to quantify the ankle-foot orthosis moment needed to regulate the joint motion.FindingsAnkle and knee joint motion were regulated according to the amount of ankle-foot orthosis moment during gait. The ankle-foot orthosis maintained the ankle angular position in dorsiflexion and knee angular position in flexion throughout a gait cycle when it generated moment from − 0.029 (0.011) to − 0.062 (0.019) Nm/kg (moment resisting plantarflexion was defined as negative).InterpretationsQuantifying the contribution of ankle-foot orthosis moment needed to regulate lower limb joints within a specific range of motion could provide valuable criteria to design an ankle-foot orthosis for individuals post-stroke.     

Effect of ankle-foot orthosis on roll-over shape in adults with hemiplegia

Ankle-foot orthoses (AFOs) are intended to improve toe clearance during swing and ankle position at initial contact (IC) and midstance. Changes that lead to improved ankle-foot kinematics may result in a more biomimetic roll-over shape (ROS). ROS is the effective geometry to which the ankle-foot complex conforms between IC and contralateral IC. An effective ROS during gait may facilitate forward progression. This study investigated the effect of an AFO on ROS in adults with hemiplegia following stroke. Kinematic and force data were recorded from 13 people with hemiplegia and 12 controls. Hemiplegic subjects walked at a self-selected speed with and without an articulated AFO with plantar flexion stop. For the involved limb, the AFO significantly increased the ROS arc length (from 32.6% to 55.7% of foot length [FL]) and arc radius (67.4% to 139.3% of FL) and significantly altered the sagittal plane location of the first center of pressure (COP) point, moving it posterior to the ankle center (-1.2% to -20% of FL) (p < 0.002 for all comparisons). However, when hemiplegic patients walked with an AFO, their mean arc radius was greater, mean arc length less, and the first COP point further posterior than those of control subjects.     

组装式下肢矫形器在偏瘫患者中的应用

对2例偏瘫患者使用了KAFO进行站立训练,11例可独立步行的偏瘫患者使用AFO进行步行训练。结果表明,偏瘫患者发病早期可使用KAFO进行站立练习,对存在尖足、内翻足的患者使用AFO可改善步行能力。     

A pilot study to investigate the combined use of Botulinum toxin type-a and ankle foot orthosis for the treatment of spastic foot in chronic hemiplegic patients

Background

Botulinum toxin is commonly used to treat spastic equinus foot. This treatment seems to improve gait in hemiplegic patients when used alone or combined with an ankle-foot orthosis. However, the nature and effects of this improvement have until now rarely been studied. The aim of this study was to quantify the impact of a Botulinum toxin injection in the triceps surae of hemiplegic patients with equinus foot, used either alone or in combination with an ankle-foot orthosis, on the kinematics and dynamics of the paretic lower limb, and to determine the advantage of combining an ankle-foot orthosis with this pharmacological treatment.

Methods

Patients were assessed using gait analysis to measure spatio-temporal, kinematic and dynamic parameters of the gait cycle before Botulinum toxin injection and then 3 and 6 weeks after injection. Eight chronic hemiplegics following central nervous system lesion were included.

Findings

Botulinum toxin injection led to an increase in velocity, peak ankle dorsiflexion during stance phase, and peak knee flexion during swing phase. It also resulted in an increased peak plantarflexion moment. Use of ankle-foot orthosis led to a specific increase in peak ankle dorsiflexion during swing phase and also increased peak plantarflexion moment.

Interpretation

The results indicate that combined Botulinum toxin injection of the triceps surae and wearing an ankle-foot orthosis is more effective than the use of Botulinum toxin only. Use of an ankle-foot orthosis increases ankle dorsiflexion during the swing phase and does not reduce the benefits gained by the use of Botulinum toxin in stance phase.     

Effect of ankle-foot orthoses on walking efficiency and gait in children with cerebral palsy

OBJECTIVE: To determine the effect of ankle-foot orthoses on walking efficiency and gait in a heterogeneous group of children with cerebral palsy, using barefoot walking as the control condition. DESIGN: A retrospective study. METHODS: Barefoot and ankle-foot orthosis data for 172 children with spastic cerebral palsy (mean age 9 years; hemiplegia: 21, diplegia: 97, and quadriplegia: 54) were compared. These data consisted of non-dimensional speed, net non- dimensional energy cost of walking (NN-cost), and NN-cost as a percentage of speed-matched controls (NN-cost(pct)). For 80 of these children the Gillette Gait Index and data for 3D gait kinematics and kinetics were also analyzed. RESULTS: Speed was 9% faster (p<0.001), NN-cost was 6% lower (p=0.007), and NN-cost(pct) was 9% lower (p=0.022) when walking with an ankle-foot orthosis. The Gillette Gait Index remained unchanged (p=0.607). Secondary subgroup analysis for involvement pattern showed a significant improvement in NN-cost(pct) only for quadriplegics (20%, p=0.004), whereas it remained unchanged for patients with hemiplegia and diplegia. Changes in the minimum knee flexion angle in stance phase and in terminal swing were found to be significantly related to the change in NN-cost(pct) (p=0.013 and p=0.022, respectively). CONCLUSION: The use of an ankle-foot orthosis resulted in a significant decrease in the energy cost of walking of quadriplegic children with cerebral palsy, compared with barefoot walking, whereas it remained unchanged in hemiplegic and diplegic children with cerebral palsy. Energy cost reduction was related to both a faster and more efficient walking pattern. The improvements in efficiency were reflected in changes of stance and swing phase knee motion, i.e. those children whose knee flexion angle improved toward the typical normal range demonstrated a decrease in energy cost of walking, and vice versa.     

半掌踝足矫形器与足跟镂空踝足矫形器对脑卒中患者步态影响的比较

目的 观察半掌踝足矫形器和足跟镂空踝足矫形器对脑卒中患者步态的影响。方法 选取符合标准的脑卒中患者25例,采用步态分析系统分别对25例脑卒中后步行功能障碍患者裸足、佩戴半掌踝足矫形器和佩戴足跟镂空踝足矫形器时的步行状态进行分析,记录三种状态下患者的步速、步频、健侧摆动相、患侧摆动相、跌倒风险和3 m起立计时行走时间,并进行统计学分析。 结果 受试者佩戴足跟镂空踝足矫形器时的步频为（86.718±17.947）Hz,较裸足和佩戴半掌踝足矫形器时均显著加快,差异均有统计学意义（P<0.05）。受试者佩戴足跟镂空踝足矫形器时的步态不对称系数为（0.086±0.070）,与裸足时比较,差异有统计学意义（P<0.05）。受试者佩戴半掌踝足矫形器和佩戴足跟镂空踝足矫形器时的3 m起立计时行走时间较裸足时均显著缩短,差异均有统计学意义(P<0.05)。受试者佩戴半掌踝足矫形器和佩戴足跟镂空踝足矫形器时的跌倒风险均显著低于裸足时,差异均有统计学意义(P<0.05);且受试者佩戴足跟镂空踝足矫形器时的跌倒风险亦显著低于佩戴半掌踝足矫形器时,差异有统计学意义（P<0.05）。 结论 佩戴半掌踝足矫形器和足跟镂空踝足矫形器均可有效纠正脑卒中患者的步态,降低其跌倒风险,且佩戴足跟镂空踝足矫形器的优势更加明显。     

Use of a static adjustable ankle-foot orthosis following tibial nerve block to reduce plantar-flexion contracture in an individual with brain injury

BACKGROUND AND PURPOSE: Ankle plantar-flexion contractures are a common complication of brain injuries and can lead to secondary limitations in mobility. CASE DESCRIPTION: The patient was a 44-year-old woman with left hemiplegia following a right frontal arteriovenous malformation resection. She had a left ankle plantar-flexion contracture of -31 degrees from neutral. After a tibial nerve block, an adjustable ankle-foot orthosis was applied 23 hours a day for 27 days. Adjustments of the orthosis were made as the contracture was reduced. The patient received physical therapy during the 27-day period for functional mobility activities and stretching the plantar flexors outside of the orthosis. OUTCOMES: The patient's dorsiflexion passive range of motion increased from -31 degrees to +10 degrees. DISCUSSION: The application of an adjustable ankle-foot orthosis following a tibial nerve block, as an addition to a physical therapy regimen of stretching and mobility training, may reduce plantar-flexion contractures in patients with brain injury.     

Material properties and application of biomechanical principles provide significant motion control performance in experimental ankle foot orthosis-footwear combination

BackgroundThis study, the first of its kind, originated with the need for a brace (an ankle foot orthosis), to constrain ankle plantarflexion and dorsiflexion within a motion threshold of <5°. A conventional thermoplastic, solid brace failed during a quasi-static loading study, informing the investigation and development of an experimental carbon composite brace, maximizing stiffness and proximity of shank and foot cylindrical shells to provide the required degree of control.MethodsTwo experiments were conducted: a quasi-static loading study, using cadaveric limbs (n = 2), and a gait study with healthy subjects (n = 14). Conditions tested were STOP, FREE, and CONTROL. Data for all studies were collected using six motion-capture cameras (Vicon, Oxford, UK; 120 Hz) tracking bone-anchored markers (cadaveric limbs) and skin-anchored markers (subjects). In the quasi-static loading study, loading conditions were congruent with the gait study. Study 1 involved a quasi-static loading analysis using cadaveric limbs, compared motion data from a conventional thermoplastic solid brace and the experimental brace. Study 2 involved quantifying ankle plantarflexion and dorsiflexion in subjects during treadmill walking, in brace STOP, FREE, and CONTROL conditions.FindingsThe experimental brace in STOP condition consistently constrained ankle plantarflexion and dorsiflexion below the motion threshold of <5°, across all studies.InterpretationCollectively, these findings demonstrate (1) that a conventional thermoplastic, solid brace was ineffective for clinical applications that required significant motion control, and (2) that ankle motion control is most effective when considered as a relationship between the brace, the ankle-foot complex, and the external forces that affect them both.     

Kinematic features of rear-foot motion using anterior and posterior ankle-foot orthoses in stroke patients with hemiplegic gait

Chen C-C, Hong W-H, Wang C-M, Chen C-K, Wu KP-H, Kang C-F, Tang SF. Kinematic features of rear-foot motion using anterior and posterior ankle-foot orthoses in stroke patients with hemiplegic gait.

Objective

To evaluate the kinematic features of rear-foot motion during gait in hemiplegic stroke patients, using anterior ankle-foot orthoses (AFOs), posterior AFOs, and no orthotic assistance.

Design

Crossover design with randomization for the interventions.

Setting

A rehabilitation center for adults with neurologic disorders.

Participants

Patients with hemiplegia due to stroke (n=14) and able-bodied subjects (n=11).

Interventions

Subjects with hemiplegia were measured walking under 3 conditions with randomized sequences: (1) with an anterior AFO, (2) with a posterior AFO, and (3) without an AFO. Control subjects were measured walking without an AFO to provide a normative reference.

Main Outcome Measures

Rear-foot kinematic change in the sagittal, coronal, and transverse planes.

Results

In the sagittal plane, compared with walking with an anterior AFO or without an AFO, the posterior AFO significantly decreased plantar flexion to neutral at initial heel contact (P=.001) and the swing phase (P<.001), and increased dorsiflexion at the stance phase (P=.002). In the coronal plane, the anterior AFO significantly increased maximal eversion to neutral (less inversion) at the stance phase (P=.025), and decreased the maximal inversion angle at the swing phase when compared with using no AFO (P=.005). The posterior AFO also decreased the maximal inversion angle at the swing phase as compared with no AFO (P=.005). In the transverse plane, when compared with walking without an AFO, the anterior AFO and posterior AFO decreased the adduction angle significantly at initial heel contact (P=.004).

Conclusions

For poststroke hemiplegic gait, the posterior AFO is better than the anterior AFO in enhancing rear-foot dorsiflexion during a whole gait cycle. The anterior AFO decreases rear-foot inversion in both the stance and swing phases, and the posterior AFO decreases the rear-foot inversion in the swing phase when compared with using no AFO.     

Kinematic effects on gait of a newly designed ankle-foot orthosis with oil damper resistance: a case series of 2 patients with hemiplegia

The ankle joint of ankle-foot orthoses (AFOs) should restrict plantarflexion to prevent foot drop during the swing phase. However, excessive plantarflexion resistance causes excessive knee flexion during the stance phase. Plantarflexion resistive moment should be easily adjustable according to the gait ability of patients with hemiplegia. Because it is difficult to adjust plantarflexion resistive moment exactly, we developed an AFO with an oil damper. It is a small shock absorber that utilizes hydraulic resistance. The oil damper generates a resistive moment to the plantarflexion rotation of the ankle joint at the initial stance phase. The magnitude of the plantarflexion resistive moment at the heel strike can be easily adjusted to accommodate each patient's condition by simply turning an adjustment screw. We used a gait analysis system to compare the gait of 2 hemiplegic patients while they were wearing either the AFO with the oil damper or the AFO with the plantarflexion stop. The AFO with the oil damper achieved sufficient plantarflexion of the ankle and mild flexion of the knee by adjusting a proper plantarflexion resistive moment during initial stance phase, and provided a more comfortable gait than did the AFOs with a plantarflexion stop.     

The effect of custom-made braces for the ankle and hindfoot on ankle and foot kinematics and ground reaction forces

OBJECTIVE: To assess the effects on gait of custom-made polypropylene orthoses: ankle-foot orthosis (AFO), rigid hindfoot orthosis (HFO-R), and articulated hindfoot orthosis (HFO-A). DESIGN: Experimental assessment. SETTING: Institutional practice, motion analysis laboratory. PARTICIPANTS: Twenty asymptomatic normative subjects. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Three-dimensional kinematics, ground reaction force, and time-related factors in 4 conditions: shoe only, and shod with the AFO, HFO-R, and HFO-A. RESULTS: The AFO and HFO-R limited sagittal and coronal plane ankle-hindfoot motion. The HFO-A limited hindfoot coronal motion while allowing normal sagittal motion. At the midfoot, the AFO and HFO-A limited transverse motion, but the HFO-A also limited sagittal and coronal motion. Use of the HFO-R resulted in exaggerated midfoot sagittal and coronal motion. Braces that limited motion to a greater degree were associated with more atypical kinetic variables, indicative of less dynamic gait. The HFO-A resulted in ground reaction forces most similar to unbraced conditions. CONCLUSIONS: Alteration in gait was affected by orthosis design. Orthoses with a rigid component crossing a joint restricted motion at that joint, but potentially compromised typical gait kinetic factors. For immobilizing the hindfoot, the HFO-A may be more comfortable and still provide more stability than the HFO-R or AFO.     

Impact of a dynamic ankle orthosis on acute pain and function in patients with mechanical foot and ankle pain

BackgroundOver two million Americans visit the doctor each year for foot and ankle pain stemming from a degenerative condition or injury. Ankle-foot orthoses can effectively manage symptoms, but traditional designs have limitations. This study investigates the acute impact of a novel “dynamic ankle-foot orthosis” (“orthosis”) in populations with mechanical pain (from motion or weight-bearing).MethodsWith and without the brace, participants (n = 25) performed standing, over-ground level walking, treadmill level walking, stair ascent, stair descent, single leg hold, squat, and sitting. Instrumented insoles captured in-shoe vertical forces and a visual analog scale was used to assess pain levels during each activity. Subsequently, the self-perceived impact of the orthosis on the patient's symptoms and function was ranked on a scale from −10 (most worsened) to +10 (most improved).FindingsPeak in-shoe force was reduced during level and stair walking (P < 0.05). Average perceived pain was 1.2 to 1.6 points lower in the orthosis than the unbraced control for the active tasks. The majority of participants reported that the brace improved their symptoms (n = 19), while a smaller group reported that the brace did not affect their symptoms (n = 5), although average function scores were improved for both groups (+2.4 to +4.5). The group of individuals with improved symptoms included cases of osteoarthritis, tendon dysfunction, chronic pain, sprains, and nerve disorders.InterpretationThe orthosis effectively improved pain symptoms and improved the ability of impaired individuals to complete functional activities of daily living such as level walking and stair walking.     

Gait and balance performance improvements attributable to ankle-foot orthosis in subjects with hemiparesis

OBJECTIVE: To assess the change in the balance performance and the improvement in the gait performance of subjects with hemiparesis, as a result of their wearing an ankle-foot orthosis. DESIGN: This was a cross-sectional control trial. Fifty-eight subjects with hemiparesis of a duration of less than 6 mos participated in this study. Each subject was evaluated for the balance and gait performance with and without an ankle-foot orthosis on the affected side. The balance activities were evaluated by the Balance Master System, and the gait performance was measured using GAITRite. RESULTS: The increase in movement velocity and the change in maximal excursion toward the affected side during the balance testing were found to be correlated significantly with the change in walking speed as a result of wearing an ankle-foot orthosis (r=0.274, P=0.039; r=0.325, P=0.020; respectively). Only the change in maximal excursion toward the affected side was found to be significantly correlated with the change in nonaffected step length (r=0.381, P=0.010). CONCLUSION: The maximal excursion toward the affected side improved as a result of wearing an ankle-foot orthosis. This correlated with an increase in step length on the nonaffected side and, hence, an improvement in the walking speed of the subjects with hemiparesis.     

Effects of elastic neutral ankle-foot orthoses on 3 dimensional parameters during gait training in patients with stroke: A pilot study

BackgroundGeneral ankle-foot orthosis (AFO) cannot be flexibly adjusted to volumetric change in the lower leg because the molding is custom-fit. Thus, we developed a flexible assistive device called elastic neutral AFO (EN-AFO) to help stroke patients hold a neutral ankle position. The purpose of this study was to investigate the effects of EN-AFO and improve gait patterns in stroke patients with rearfoot varus deformity.MethodsFifteen stroke patients with a varus deformity of the foot performed a walking test with and without the use of EN-AFO. Kinematic data were measured with a 3D motion analysis system with inertial measurement unit (IMU) sensors.ResultsIn the stance phase, maximal pelvic tilt and maximal ankle dorsiflexion in the affected side changed, and maximal and minimal pelvic tilts and maximal hip abduction in the less-affected limb effectively changed, as well. During the swing phase, minimal pelvic tilt and minimal ankle abduction in the affective limb greatly changed; particularly, the reduction of maximal ankle inversion was significantly cleared.ConclusionsThe EN-AFO was effective in controlling the tendency of foot inversion in patients with varus deformities. This is suitable for gait training, as it can adjust the orthosis stiffness according to the foot condition.     

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.     

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.     

Immediate effect of different ankle-foot orthosis functions with the same dorsiflexed setting of initial ankle joint angle on walking ability in individuals with chronic stroke: a randomized crossover trial

[Purpose] To investigate how different ankle-foot orthosis functions with the same dorsiflexed setting of initial ankle joint angle affect the walking ability in individuals with chronic stroke. [Participants and Methods] In this randomized crossover study, participants underwent a 10-m walking test and walked on a WalkWay MW-1000 three times under these conditions: (1) without ankle-foot orthosis; (2) with ankle-foot orthosis with an adjustable posterior strut at 5° of fixed dorsiflexion; and (3) with ankle-foot orthosis with an adjustable posterior strut at 5–20° of restricted dorsiflexion. The primary outcome was walking speed on the 10-m walking test. The secondary outcomes were walking speed and spatiotemporal factors measured by the WalkWay MW-1000. [Results] Fifteen individuals (mean [standard deviation] age, 60.9 [8.6] years; male, 12) were enrolled. Walking speeds of the ankle-foot orthosis with fixed and restricted dorsiflexion groups were significantly higher than those without the orthosis; however, no outcomes differed significantly between ankle-foot orthosis with fixed versus restricted dorsiflexion groups. [Conclusion] In individuals with chronic stroke, ankle-foot orthosis function may be less important than the dorsiflexed setting of initial ankle joint angle in the ankle-foot orthosis.     

Gait characteristics of persons with bilateral transtibial amputations

The gait characteristics of persons with unilateral transtibial amputations are fairly well documented in the literature. However, much less is known about the gait of persons with bilateral transtibial amputations. This study used quantitative gait analysis to investigate the gait characteristics of 19 persons with bilateral transtibial amputations. To reduce variability between subjects, we fitted all subjects with Seattle Lightfoot II feet 2 weeks before their gait analyses. The data indicated that subjects walked with symmetrical temporospatial, kinematic, and kinetic parameters. Compared with nondisabled controls, the subjects with amputations walked with slower speeds and lower cadences, had shorter step lengths and wider step widths, and displayed hip hiking during swing phase. Additionally, compared with the nondisabled controls walking at comparable speeds, the subjects with amputations demonstrated reduced ankle dorsiflexion and knee flexion in stance phase, reduced peak ankle plantar flexor moment, reduced positive ankle power (i.e., energy return) in late stance, and increased positive and negative hip power. These results demonstrate the deficiencies in current prosthetic componentry and suggest that further research is needed to enhance prosthesis function and improve gait in persons with amputations.