Ankle-foot orthoses: effect on gait abnormalities in tibial nerve paralysis

To study the biomechanical effects of gastrocnemius-soleus dysfunction and its potential remediation, the gait patterns of six able-bodied young adults were analyzed before and after induced temporary tibial nerve paralysis. Ambulation with the tibial nerve block was performed with and without the assistance of an ankle-foot orthosis (AFO) with a rigid anterior stop adjusted to either 5 degrees plantarflexion or 5 degrees dorsiflexion. The gait abnormalities resulting from tibial nerve paralysis include delayed advancement of the center of pressure, delayed ipsilateral heeloff and early contralateral heelstrike, decreased steplength, decreased ankle dorsiflexion moment, and increased knee flexion moment. This study provides quantitative information on the degree to which these abnormalities were corrected by appropriately adjusted AFOs. When using an AFO with an anterior stop, subjects with tibial nerve paralysis had improved advancement of the center of pressure (p less than 0.01). The body's ground reactive force line moved forward more normally, pivoting over the metatarsal head area and raising the heel earlier than observed with uncorrected tibial nerve paralysis, thus approximating the normal ankle dorsiflexion moment, normal timing of gait events, normal advancement of the hip, and normal steplength. The AFO with the anterior stop set at 5 degrees plantarflexion was more effective in restoring the values to normal than the AFO with the anterior stop set at 5 degrees dorsiflexion, but still did not consistently achieve the normal values. Only by using the AFO with the anterior stop set at 5 degrees plantarflexion was the increased knee flexion moment observed during the block reduced to normal levels (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

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.     

The impact of simulated ankle plantarflexion contracture on the knee joint during stance phase of gait: A within-subject study

Background

Ankle plantarflexion contractures are common in adults with neurological disorders and known to cause secondary gait deviations. However, their impact on the knee joint is not fully understood. The aims of this study are to describe the effect of simulated plantarflexion contractures on knee biomechanics during the stance phase and on the spatiotemporal characteristics of gait.

Methods

Mild (10–degree plantarflexion) and severe (20–degree plantarflexion) ankle contractures were simulated in thirteen able-bodied adults using an ankle-foot-orthosis. A no contracture condition was compared with two simulated contracture conditions.

Findings

There was an increase in knee extension, sometimes resulting in hyperextension, throughout stance for the two contracture conditions compared to the no contracture condition (mean increase in knee extension ranged from 5° to 9°; 95% CI 0° to 17°). At the same time, there were reductions in extension moment and power generation at the knee. Simulated plantarflexion contractures also reduced gait velocity, bilateral step length and cadence. All these changes were more pronounced in the severe contracture condition than mild contracture condition. While the majority of participants adopted a foot-flat pattern on landing and exhibited an increase in knee extension during stance, two participants used a toe-walking pattern and exhibited an increase in knee flexion.

Interpretation

Ankle plantarflexion contractures are associated with an increase in knee extension during stance phase. However, some people with simulated ankle contractures may walk with an increase in knee flexion instead. Ankle plantarflexion contractures also adversely affect gait velocity, step length and cadence.     

The effect of ankle–foot orthosis plantarflexion stiffness on ankle and knee joint kinematics and kinetics during first and second rockers of gait in individuals with stroke

BackgroundStiffness of an ankle–foot orthosis plays an important role in improving gait in patients with a history of stroke. To address this, the aim of this case series study was to determine the effect of increasing plantarflexion stiffness of an ankle–foot orthosis on the sagittal ankle and knee joint angle and moment during the first and second rockers of gait.MethodsGait data were collected in 5 subjects with stroke at a self-selected walking speed under two plantarflexion stiffness conditions (0.4 Nm/° and 1.3 Nm/°) using a stiffness-adjustable experimental ankle–foot orthosis on a Bertec split-belt fully instrumented treadmill in a 3-dimensional motion analysis laboratory.FindingsBy increasing the plantarflexion stiffness of the ankle–foot orthosis, peak plantarflexion angle of the ankle was reduced and peak dorsiflexion moment was generally increased in the first rocker as hypothesized. Two subjects demonstrated increases in both peak knee flexion angle and peak knee extension moment in the second rocker as hypothesized. The two subjects exhibited minimum contractility during active plantarflexion, while the other three subjects could actively plantarflex their ankle joint.InterpretationIt was suggested that those with the decreased ability to actively plantarflex their ankle could not overcome excessive plantarflexion stiffness at initial contact of gait, and as a result exhibited compensation strategies at the knee joint. Providing excessively stiff ankle–foot orthoses might put added stress on the extensor muscles of the knee joint, potentially creating fatigue and future pathologies in some patients with stroke.     

A computer simulation of human walking in persons with joint contractures

Joint contractures decrease the patient's ability to walk, but usually other parts of the body compensate the affected joint contractures. When we restore the gait performance in paraplegic patients by means of functional electrical stimulation, however, we cannot expect complications of compensation. A computer simulation was done to clarify how the contractures affect the gait pattern when no complications of compensation were expected. A seven-segment link mechanical model was used for simulation of human walking in the sagittal plane. In turn, using a personal computer stance and swing-leg joint contractures of the ankle, knee, and/or hip were simulated. When stance-leg contracture was simulated, step length became short with increasing hip flexion contracture. The trunk was tilted backward during knee flexion or ankle plantarflexion contracture simulation. When the swing-leg contracture was simulated, step length became short with increasing knee flexion contracture. We found that hip or knee flexion contracture of < or = 15 degrees, or ankle plantarflexion contracture of < 0 degrees was required to maintain positive step length and forward movement of the center of gravity. These findings suggest that 15 degrees of hip and knee flexion contracture, and 0 degrees of ankle plantarflexion contracture are critical when gait restoration is performed by functional electrical stimulation.     

The effect of hinged ankle-foot orthoses on sit-to-stand transfer in children with spastic cerebral palsy

OBJECTIVE: To investigate the effectiveness of the hinged ankle-foot orthosis (AFO) on sit-to-stand (STS) transfers in children with spastic cerebral palsy. DESIGN: Before-after trial. SETTING: University-affiliated hospital. PARTICIPANTS: Nineteen spastic diplegic children (age range, 2-6 y). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The transitional movement of STS was tested in random order with children while wearing the barefoot and hinged AFOs. The temporal, kinematic, and kinetic data during the task were collected by using a motion analyzer (with 6 infrared cameras). Statistical comparison between barefoot and hinged AFO was done with the Wilcoxon signed-rank test. RESULTS: Total duration of STS transfer was significantly shortened with the hinged AFO (P <.05). The initial knee flexion, the initial angle, and the final angle of ankle dorsiflexion were increased with the AFO, compared with when barefoot (P <.05). However, the increased pelvic tilt and hip flexion while barefoot was not reduced with the AFO. The maximal moment and power of hip and knee joints were significantly increased with the AFO (P <.05), whereas the maximal moment and power of the ankle joint were not significantly changed when wearing the AFO. CONCLUSIONS: Although proximal compensatory strategy of increased pelvic tilt and hip flexion did not change with the hinged AFO, some improvements of temporal, kinematic, and kinetic parameters were identified during the task. These findings suggest that a hinged AFO is beneficial for STS transfer activity for children with spastic diplegia.     

Effects of a knee–ankle–foot orthosis on gait biomechanical characteristics of paretic and non-paretic limbs in hemiplegic patients with genu recurvatum

Background

A knee–ankle–foot orthosis may be prescribed for the prevention of genu recurvatum during the stance phase of gait. It allows also to limit abnormal plantarflexion during swing phase. The aim is to improve gait in hemiplegic patients and to prevent articular degeneration of the knee. However, the effects of knee–ankle–foot orthosis on both the paretic and non-paretic limbs during gait have not been evaluated. The aim of this study was to quantify biomechanical adaptations induced by wearing a knee–ankle–foot orthosis, on the paretic and non-paretic limbs of hemiplegic patients during gait.

Methods

Eleven hemiplegic patients with genu recurvatum performed two gait analyses (without and with the knee–ankle–foot orthosis). Spatio-temporal, kinematic and kinetic gait parameters of both lower limbs were quantified using an instrumented gait analysis system during the stance and swing phases of the gait cycle.

Findings

The knee–ankle–foot orthosis improved spatio-temporal gait parameters. During stance phase on the paretic side, knee hyperextension was reduced and ankle plantarflexion and hip flexion were increased. During swing phase, ankle dorsiflexion increased in the paretic limb and knee extension increased in the non-paretic limb. The paretic limb knee flexion moment also decreased.

Interpretation

Wearing a knee–ankle–foot orthosis improved gait parameters in hemiplegic patients with genu recurvatum. It increased gait velocity, by improving cadence, stride length and non-paretic step length. These spatiotemporal adaptations seem mainly due to the decrease in knee hyperextension during stance phase and to the increase in paretic limb ankle dorsiflexion during both phases of the gait cycle.     

痉挛型脑瘫儿童佩戴不同类型踝足矫形器后下肢生物力学的变化

目的：比较痉挛型脑瘫患儿在佩戴传统硬直式踝足矫形器（RAFO）与新型动力型踝足矫形器（DAFO）后所产生的下肢生物力学变化及差异,为临床选用更合适的踝足矫形器（AFO）进行治疗提供理论依据。方法：采用Vicon三维步态分析系统及Kislter测力台分别测评16例痉挛型脑瘫患儿在裸足、佩戴RAFO及DAFO 3种条件下的下肢关节运动学,动力学以及时间空间参数。结果：与裸足比较,佩戴RAFO后步长增加0.05 m,DAFO增加0.07 m;首次着地RAFO增加9°,DAFO增加11.3°;支撑相中RAFO增加10°,DAFO增加11°,且2种方法踝关节背屈角度均明显增大,跖屈角度明显减小;跖屈力矩RAFO增加0.33 Nm/kg,DAFO增加0.37 Nm/kg（均P〈0.05）。DAFO的踝关节活动范围较RAFO增加7°（P〈0.05）。结论：2种不同的踝足矫形器均能够有效提高痉挛型脑瘫患儿的步行能力及行走过程中的踝关节背伸功能。DAFO在矫正踝关节活动及马蹄足畸形方面效果好于RAFO,并可减轻RAFO所导致的踝关节功能受限。     

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     

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.     

Gait patterns of transtibial amputee patients walking indoors barefoot

OBJECTIVE: To evaluate the gait patterns of lower limb amputee patients walking with and without shoes and to identify differences in barefoot gait patterns when using different prosthetic feet. DESIGN: Optoelectronic three-dimensional motion analysis of gait was performed on six transtibial amputees using a solid ankle cushion heel foot and a single-axis foot, both with and without shoes. RESULTS: Gait abnormalities were observed during barefoot walking when the solid ankle cushion heel foot was used. These included knee joint hyperextension of 9.9 +/- 2.0 degrees and the loss of ankle plantar flexion in the early stance phase. When the single-axis foot was used, knee flexion thrust declined from 9.9 +/- 3.7 degrees to 7.2 +/- 3.8 degrees and ankle plantar flexion decreased from 9.9 +/- 2.8 degrees to 7.0 +/- 2.1 degrees during the early stance phase. CONCLUSIONS: In transtibial amputees, significant gait abnormalities were observed during barefoot walking using the solid ankle cushion heel foot. These gait patterns improved, however, with use of a single-axis prosthetic foot, which permits a further plantar flexion after the initial contact.     

Kinematic Analysis of Gait Following Intra-articular Corticosteroid Injection into the Knee Joint with an Acute Exacerbation of Arthritis

Purpose: The objective of this study was to examine the effects of intra-articular corticosteroid injection (ICI) on ipsilateral knee flexion/extension, ankle dorsiflexion/plantarflexion (DF/PF), and hip abduction/adduction (abd/add) during stance phase in people with an acute exacerbation of rheumatoid arthritis (RA) of the knee joint. The study also assessed the effects of ICI on spatiotemporal parameters of gait and functional status in this group.Methods: Nine people with an exacerbation of RA of the knee were recruited. Kinematic and spatiotemporal gait parameters were obtained for each participant. Knee-related functional status was assessed using the Knee injury and Osteoarthritis Outcome Score (KOOS). Spatiotemporal gait parameters and joint angles (knee flexion, ankle DF/PF, hip abd/add) of the affected side were compared pre- and post-ICI.Results: Data for eight people were available for analysis. Median values for knee flexion and ankle PF increased significantly following ICI. Gait parameters of cadence, velocity, bilateral stride length, bilateral step length, step width, double-support percentage, and step time on the affected side also showed improvement. Pain and knee-related functional status as measured by the KOOS showed improvement.Conclusions: This study demonstrated a beneficial short-term effect of ICI on knee-joint movements, gait parameters, and knee-related functional status in people with acute exacerbation of RA of the knee.     

Gait abnormalities in hemiplegia: their correction by ankle-foot orthoses

Hemiparetic gait is characterized by slow speed and poorly coordinated movements. Because the values of gait parameters vary with changes in speed, the slow speed that is typical of hemiparetic gait necessitates applying controls for the influence of speed when comparing hemiparetic and able-bodied persons. Gait kinetics and kinematics were measured in seven hemiparetic and seven able-bodied adults to compare their gait patterns at similar speeds and to assess the effectiveness of ankle-foot orthoses which were double-stopped in 5 degrees of dorsiflexion or 5 degrees of plantarflexion. Hemiparetic persons ambulating without the orthoses had a shorter step length, longer duration stance, and shorter duration swing than normal. They displayed greater than normal flexion of the affected hip during midstance, which, by putting the center of mass farther in front of the knee, may explain the increased knee extension moment due to vertical force. Affected hip adduction during single support was less in hemiparetic persons than in able-bodied persons, indicating a decreased lateral shift to the paretic side. During the swing phase, the affected limbs of hemiparetic persons were in less knee flexion and less dorsiflexion than normal, necessitating circumduction to achieve toe clearance. Ankle-foot orthoses increased walking speed to normalize heelstrike duration through use of an optimally adjusted plantarflexion stop. An improperly adjusted orthosis may produce an exaggerated knee flexion moment resulting in knee instability.     

单侧小腿截肢患者穿假肢后的步态运动学参数研究

目的 采用计算机辅助康复环境(CAREN)步态评估系统分析单侧小腿截肢患者穿假肢后的步态运动学参数,并分析其产生差异的原因。 方法 选取单侧小腿中段截肢但均装配假肢的受试者9例设为假肢组,同期选择健全受试者11例设为标准组,通过CAREN步态评估系统对2组受试者的步态运动学参数进行收集、处理、分析,并根据分析报告阐明产生差异原因。 结果 假肢组步态时相性指数为(0.88±0.04),其假肢侧的步长、支撑期百分比、髋关节支撑期最大伸展角度、膝关节支撑期最大屈曲角度、踝关节足跟着地背屈角度、踝关节支撑期最大背屈角度、踝关节支撑期最大跖屈角度与健侧比较,差异均有统计学意义(P<0.05）。假肢组假肢侧的步行速度、步态周期、跨步长、支撑期百分比、髋关节足跟落地屈髋角度、髋关节支撑期最大伸展角度、髋关节支撑期最大屈曲角度、膝关节足跟着地屈膝角度、踝关节足跟着地背屈角度、踝关节支撑期最大跖屈角度、踝关节支撑期最大背屈角度与标准组双侧均值比较,差异均有统计学意义(P<0.05）。 结论 单侧小腿截肢者穿戴假肢后步态时相对称性为（0.88±0.04）,假肢侧踝关节运动学参数显著弱于自身健侧,其时空与运动学参数也显著弱于健全人。     

The effect of fixed ankle foot orthoses in children with cerebral palsy

Purpose.?To identify the characteristics of children with cerebral palsy who benefited from tuning of their fixed ankle foot orthoses (AFOs) to create a screening tool.

Method.?A retrospective review was conducted using video records of 21 independently walking children with cerebral palsy who were referred to a Gait Laboratory for AFO tuning. All showed a ground reaction vector (GRV) in front of the knee (extending) when barefoot. The stance phase was digitised to obtain kinematic and kinetic parameters. Effectiveness of AFO tuning was judged by optimisation of the GRV at the knee and statistical and scatter plot analysis sought to discriminate between those who tuned and those who did not.

Results.?Analysis showed clear distinction between the two groups based on knee kinematics. Those who tuned showed flexion of no more than 20° in the first third of stance combined with movement towards extension in the second third of stance to a minimum of 10° flexion or less.

Conclusions.?This study has created a screening tool to identify children likely to benefit from AFO tuning based on kinematic data and which could be used in the community.     

Gait performance with compensatory adaptations in stroke patients with different degrees of motor recovery

OBJECTIVE: Gait patterns vary among stroke patients. This study attempted to discover gait performance with compensatory adaptations in stroke patients with different degrees of motor recovery. DESIGN: Data were gathered from 35 stroke patients and 15 healthy subjects. Gait performance and motor recovery were assessed 6 mos after stroke. Stroke patients further were divided into poor and good groups. The walking velocity was correlated with Brunnstr?m's stages, and the temporal stride and motion variables of the two groups were compared. RESULTS: Walking velocity was positively correlated with the Brunnstr?m's stages of the proximal lower limb. The poor group displayed slower walking velocity and shorter single-support time compared with the good group. Both groups displayed low maximum excursion of hip extension and ankle plantarflexion during the stance phase and low maximum excursion of hip and knee flexion and ankle dorsiflexion during the swing phase. Moreover, both groups displayed excessive pelvic tilts during the stance and swing phases. However, the poor group displayed different pelvic motion and timing sequences to each peak joint angle from normal subjects and the good group. Peak hip and knee angles of the affected limb during the stance phase occurred almost simultaneously in this group. CONCLUSIONS: Selective control of the proximal lower limb may be the main determinant of walking velocity. The compensatory adaptations were similar, except for pelvic motion, in stroke patients with different levels of motor recovery, whereas the poor group walked with synergistic mass patterns and reduced stability.     

Gait abnormalities in peroneal nerve paralysis and their corrections by orthoses: a biomechanical study

Stroke, brain injury, incomplete spinal cord injuries, and peripheral neuropathies frequently result in dysfunction of the foot dorsiflexors and evertors. A controlled examination of aspects of these disabilities was conducted with normal volunteers who underwent a temporary peroneal nerve block. The effects of peroneal nerve paralysis were analyzed to quantitatively describe the resulting gait abnormalities and to assess the effectiveness of orthoses in restoring a normal gait pattern. Kinematic and kinetic measurements were made during normal ambulation, ambulation with a right peroneal nerve paralysis, and ambulation with a paralysis and an ankle-foot orthosis (AFO) with three different adjustments: a posterior stop set in 5 degrees plantarflexion, a posterior stop set in 5 degrees dorsiflexion, and spring-assisted dorsiflexion. The peroneal paralysis produced abnormalities during both the stance and swing phases of gait. During early stance there was a decrease in the length of the heelstrike phase and a reduction in the peak plantarflexion moment (p less than 0.01). During midstance there was an increase in the range of inversion-eversion achieved suggesting medial-lateral instability (p less than 0.01). The second vertical force peak and the aft-shear force peak were reduced (p less than 0.05) as were the peak dorsiflexion moment and the opposite steplength (p less than 0.01). These reductions are believed to be due to medial-lateral instability during pushoff. Subjects demonstrated a steppage gait during swing phase and increased inversion just prior to heelstrike (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

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.