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

Articulated ankle-foot orthoses associated with home-based task-specific training improve functional mobility in patients with stroke: a randomized clinical trial

INTRODUCTION

We compared fixed and articulated ankle-foot orthoses (AFOs) in home-based mobility tasks to assess short-term mobility, dynamic balance, quality of life, anxiety/depression, disability level, stroke severity, autonomy, human functioning, and patient satisfaction.

METHODS

This was a two-arm, parallel-group, randomized controlled trial with concealed allocation, assessor blinding, and a complete case analysis involving patients with chronic stroke. The participants were randomized into two groups: fixed (n = 24) and articulated (n = 23) AFOs. The AFOs were custom-fabricated, and both groups performed four-week home-based mobility tasks five days weekly. Primary outcome measures included changes in balance and mobility assessed using the Tinetti Performance-Oriented Mobility Assessment (POMA), Timed Up and Go (TUG) test, and Functional Ambulation Category (FAC). Secondary outcomes included quality of life, anxiety/depression, disability, stroke severity, autonomy, human functioning, and patient satisfaction.

RESULTS

In a between-group comparison, after adjusting for age, sex, stroke severity, and thrombolysis, the articulated AFO group showed better performance in the TUG test (p = 0.020; d = 0.93), POMA-Gait (p = 0.001; d = 0.53), POMA-Total (p = 0.048; d = 0.98), and FAC (p = 0.003; d = 1.03) than the fixed AFO group. Moreover, significant difference was noted in human functioning (moving around using equipment)between the groups (p = 0.047; d = 92).

CONCLUSION

A program involving home-based mobility tasks and articulated AFOs improved functional mobility after stroke.

A proposed evidence-guided algorithm for the adjustment and optimization of multi-function articulated ankle-foot orthoses in the clinical setting

Individuals with neuromuscular pathologies are often prescribed an ankle-foot orthosis (AFO) to improve their gait mechanics by decreasing pathological movements of the ankle and lower limb. AFOs can resist or assist excessive or absent muscular forces that lead to tripping, instability, and slow inefficient gait. However, selecting the appropriate AFO with mechanical characteristics, which limit pathological ankle motion in certain phases of the gait cycle while facilitating effective ankle movement during other phases, requires careful clinical decision-making. The aim of this study is to propose an explicit methodology for the adjustment of multi-function articulated AFOs in clinical settings. A secondary aim is to outline the evidence supporting this methodology and to identify gaps in the literature as potential areas for future research. An emerging class of AFO, the multi-function articulated AFO, offers features that permit more comprehensive, iterative, and reversible adjustments of AFO ankle alignment and resistance to ankle motion. However, no standard method exists for the application and optimization of these therapeutic devices in the clinical setting. Here we propose an evidence-guided methodology applicable to the adjustment of multi-function articulated AFOs in the clinical setting. Characteristic load-deflection curves are given to illustrate the idealized yet complex resistance-angle behavior of multi-function articulated AFOs. Research is cited to demonstrate how these mechanical characteristics can help mitigate specific pathologic ankle and knee kinematics and kinetics. Evidence is presented to support the effects of systematic adjustment of high resistance, alignable, articulated AFOs to address many typical pathomechanical patterns observed in individuals with neuromuscular disorders. The published evidence supporting most decision points of the algorithm is presented with identified gaps in the evidence. In addition, two hypothetical case examples are given to illustrate the application of the method in optimizing multi-function articulated AFOs for treating specific gait pathomechanics. This method is proposed as an evidence-guided systematic approach for the adjustment of multi-function articulated AFOs. It utilizes observed gait deviations mapped to specific changes in AFO alignment and resistance settings as a clinical tool in orthotic treatment for individuals with complex neuromuscular gait disorders.

Effect of a rigid ankle foot orthosis and an ankle foot orthosis with an oil damper plantar flexion resistance on pelvic and thoracic movements of patients with stroke during gait

BACKGROUND

Impairments of trunk movements in gait of stroke are often reported. Ankle foot orthosis (AFO) is commonly used to improve gait of stroke; however, the effect of different types of AFOs on the pelvic and thoracic movements during gait in stroke has not been clarified.

METHODS

Thirty-four patients with stroke were randomly allocated to undergo 2 weeks of gait training by physiotherapists while wearing a rigid AFO (RAFO) with a fixed ankle or an AFO with an oil damper (AFO-OD) that provides plantarflexion resistance and free dorsiflexion. A motion capture system was used for measurements of shod gait without AFO at baseline and with and without AFO after gait training. Two-way repeated ANOVA, Wilcoxon signed-rank test, and Mann-Whitney U test were performed for the data after the gait training to know the effect of different kinds of AFOs.

RESULTS

Twenty-nine patients completed the study (AFO-OD group: 14, RAFO group: 15). Interactions were found in pelvic rotation angle, change of shank-to-vertical angle (SVA) in the stance, and paretic to non-paretic step length, which increased in AFO-OD group with AFOs (p < 0.05), while the SVA decreased in RAFO group with AFOs (p < 0.05). The main effects were found in pelvic rotation at the contralateral foot off, and thoracic tilt at foot off when an AFO was worn. The change of SVA in stance was positively correlated with the pelvic rotation in the AFO-OD group (r = 0.558). At initial contact, pelvic rotation was positively correlated with thoracic rotation in both groups.

CONCLUSIONS

The findings in 29 patients with stroke showed that pelvic and thoracic movements especially the rotation were affected by the type of AFOs. Pelvic rotation and lower limb kinematics exhibited significant improvements with AFO-OD, reflecting more desirable gait performance. On the other hand, the increase in thoracic in-phase rotation might expose the effect of insufficient trunk control and dissociation movement. Trial registration UMIN000038694, Registered 21 November 2019, https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_his_list.cgi?recptno=R000044048 .

Observations on the kinematic characteristics of the healthy side of the knee in stroke patients: A cross-sectional study

The abnormal gait of stroke patients not only severely limits the recovery of their walking ability, but also seriously affects their quality of daily life. Previous observational studies have focused too much on the observation of single degree of freedom and axial knee motion angles in stroke patients. Changes in the multi-degree of freedom and multi-axial joint angles of the knee have been less frequently observed, leading to somewhat limited conclusions. Therefore, the aim of this study was to use the Opti-knee motion test to analyze in real time the motion of the knee in all directions on the healthy side of stroke patients and to compare it with normal gait to provide a clinical basis for subsequent rehabilitation. In a cross-sectional study, 120 subjects (60 stroke patients were as the observation group and 60 healthy subjects as the control group) were studied. Both groups of subjects were tested for Opti-Knee tri-axial angles of motion of the healthy side of the knee, including flexion and extension, internal and external rotation, internal and external turning, anterior and posterior displacement, superior and inferior displacement, left and right displacement, maximum extension angle and maximum flexion angle. Compared with the control group, there were significant changes in the joint angles of flexion and extension, internal and external rotation, internal and external turning, maximum extension and maximum flexion of the knee on the healthy side in the observation group, and the differences were statistically significant [95%(37.22, 45.13), P = .01], [95%(9.51,13.67), P = .018], [95%(4.82,7.57), P = .049], [95%(4.12, 8.63), P = .019], [95%(51.68, 57.28), P = .0001]. However, there was no significant change in the angle of motion of the healthy side of the knee for anterior-posterior displacement, superior-inferior displacement and internal-external displacement in either group and the differences were not statistically significant [95%(1.16, 1.78), P = .72], [95%(0.85,1.32), P = .32], [95%(0.57, 0.88), P = .36]. This study confirms the importance of changes in the angle of motion of the knee on the side of the stroke patient in maintaining the stability of the knee joint. Therefore, their bilateral lower limb symmetry training should be paid attention to in the subsequent rehabilitation treatment.

Effect of trim line on stiffness in dorsi- and plantarflexion of posterior leaf spring ankle-foot orthoses

[Purpose] This study aimed to objectively clarify the effect of the trim line setting on the stiffness of posterior leaf spring ankle-foot orthoses. [Participant and Methods] Posterior leaf spring ankle-foot orthoses were fabricated with two thickness levels and three trim line conditions for the posterior upright width and the dorsi- and plantarflexion moments and stiffness exhibited by the orthoses were measured using an evaluation tester. [Results] The trim line of the posterior upright width affected the dorsiflexion moment generated by the orthoses in plantarflexion. [Conclusion] A strong linear correlation was found between posterior upright width and orthotic stiffness, suggesting that it is highly feasible to standardize orthotic settings according to individual conditions of patients after stroke, even for posterior leaf spring ankle-foot orthoses.

The effects of footplate stiffness on push-off power when walking with posterior leaf spring ankle-foot orthoses

BACKGROUND

Many studies on ankle-foot orthoses investigated the optimal stiffness around the ankle, while the effect of footplate stiffness has been largely ignored. This study investigated the effects of ankle-foot orthosis footplate stiffness on ankle-foot push-off power during walking in able-bodied persons.

METHODS

Twelve healthy participants walked at a fixed speed (1.25 m·s^-1) on an instrumented treadmill in four conditions: shod and with a posterior leaf-spring orthosis with a flexible, stiff or rigid footplate. For each trial, ankle kinematics and kinetics were averaged over one-minute walking. Separate contributions of the ankle joint complex and distal hindfoot to total ankle-foot power and work were calculated using a deformable foot model.

FINDINGS

Peak ankle joint power was significantly higher with the rigid footplate compared to the flexible and stiff footplate and not different from shod walking. The stiff footplate increased peak hindfoot power compared to the flexible and rigid footplate and shod walking. Total ankle-foot power showed a significant increase with increasing footplate stiffness, where walking with the rigid footplate was comparable to shod walking. Similar effects were found for positive mechanical work.

INTERPRETATION

A rigid footplate increases the lever of the foot, resulting in an increased ankle moment and energy storage and release of the orthosis' posterior leaf-spring as reflected in higher ankle joint power. This effect dominates the power generation of the foot, which was highest with the intermediate footplate stiffness. Future studies should focus on how tuning footplate stiffness could contribute to optimizing ankle-foot orthosis efficacy in clinical populations.

The effects of ankle-foot orthoses on walking speed in patients with stroke: a systematic review and meta-analysis of randomized controlled trials

Objective:

The aim of this study was to evaluate the effects of ankle-foot orthoses on speed walking in patients with stroke.

Data sources:

PubMed, Embase, Web of Science, Scopus, CENTRAL, PEDro, RehabData, RECAL, and ProQuest were searched from inception until 30 September 2019.

Review methods:

This study was conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guideline statement. Risk of bias assessment was performed using the Cochrane Risk of Bias Tool. Begg’s test and Egger’s regression method were used to assess the publication bias. Trim and fill analysis was also used to adjust any potential publication bias. Sensitivity analysis was performed to evaluate the effect of individual studies. The quality of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria.

Results:

Overall, 14 studies were included with a total of 1186 participants. A small-to-moderate and non-significant improvement in favor of the ankle-foot orthosis versus without ankle-foot orthosis (standardized mean difference (SMD) = 0.41, 95% confidence interval = −0.15 to 0.96), similar effects of ankle-foot orthosis and functional electrical stimulation (SMD = 0.00, 95% confidence interval = −0.16 to 0.16), and a small and non-significant improvement in favor of ankle-foot orthosis versus another type of ankle-foot orthosis (SMD = 0.22, 95% confidence interval = −0.05 to 0.49) in walking speed were found. However, the quality of evidence for all comparisons was low or very low.

Conclusion:

Despite reported positive effects in some studies, there is no firm evidence of any benefit of ankle-foot orthoses on walking speed.

The impact of ankle-foot orthosis stiffness on gait: A systematic literature review

BACKGROUND

Ankle-foot orthoses (AFOs) are commonly prescribed to provide ankle support during walking. Current prescription standards provide general guidelines for choosing between AFO types, but are limited in terms of guiding specific design parameter choices. These design parameters affect the ankle stiffness of the AFO.

RESEARCH QUESTION

The aim of this review was to investigate the impact of AFO stiffness on walking mechanics.

METHODS

A literature search was conducted using three databases: Pubmed, Engineering Village, and Web of Science.

RESULTS

After applying the exclusion criteria, 25 of 287 potential articles were included. The included papers tested a range of stiffnesses (0.02-8.17 Nm/deg), a variety of populations (e.g. healthy, post-stroke, cerebral palsy) and various gait outcome measures. Ankle kinematics were the most frequently reported measures and the most consistently affected by stiffness variations. Greater stiffnesses generally resulted in reduced peak ankle plantarflexion, dorsiflexion, and total range of motion, as well as increased dorsiflexion at initial contact. At the knee, a few studies reported increased flexion at initial contact, and decreased peak extension and increased peak flexion during stance when stiffness was increased. Stiffness did not affect hip kinetics and there was low evidence for its effects on hip or pelvis kinematics, ankle and knee kinetics, muscle activity, metabolic cost, ground reaction forces and spatiotemporal parameters. There were no generalizable trends for the impact of stiffness on user preference.

SIGNIFICANCE

AFO stiffness is a key factor influencing ankle movement. Clear reporting standards for AFO design parameters, as well as additional high quality research is needed with larger sample sizes and different clinical populations to ascertain the true effect of stiffness on gait.

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

Mechanical tuning of an ankle-foot orthosis (AFO) is important in improving gait in individuals post-stroke. Alignment and resistance are two factors that are tunable in articulated AFOs. The aim of this study was to investigate the effects of changing AFO ankle alignment on lower limb joint kinematics and kinetics with constant dorsiflexion and plantarflexion resistance in individuals post-stroke. Gait analysis was performed on 10 individuals post-stroke under four distinct alignment conditions using an articulated AFO with an ankle joint whose alignment is adjustable in the sagittal plane. Kinematic and kinetic data of lower limb joints were recorded using a Vicon 3-dimensional motion capture system and Bertec split-belt instrumented treadmill. The incremental changes in the alignment of the articulated AFO toward dorsiflexion angles significantly affected ankle and knee joint angles and knee joint moments while walking in individuals post-stroke. No significant differences were found in the hip joint parameters. The alignment of the articulated AFO was suggested to play an important role in improving knee joint kinematics and kinetics in stance through improvement of ankle joint kinematics while walking in individuals post-stroke. Future studies should investigate long-term effects of AFO alignment on gait in the community in individuals post-stroke.

Effectiveness of robo-assisted lower limb rehabilitation for spastic patients: A systematic review

BACKGROUND

Though many rehabilitative treatments are available for treatment of spasticity, thus the effectiveness of different robo-rehabilitative devices needs to be evaluated through a systematic review.

OBJECTIVE

The objective of this study is to focuses on the efficacy of Robot assistive rehabilitation device for the removal of spasticity from the lower limb of Spastic patients.

DATA SOURCESSOURCES

PubMed, Web of Sciences, EMBASE (Excerpta Medical database), CDSR (Cochrane database of systematic reviews), Scopus, IEEE Xplore, Wiley online library, MEDLINE (OvidSP), Science Direct, Springer Link were from January 1980 to September 2017 DATA EXTRACTIONEXTRACTION: Seventy-one publications from eleven databases published were selected using keywords Ankle foot, spasticity, robotic rehabilitation, efficacy of robotics and Ankle foot rehabilitation. The review is narrowed down to twenty-six articles which were selected for they focused on effects of Robot assistive rehabilitation device quantitatively.

RESULT

A quantitative study from analyzing 26 studies comprising of 786 subjects is carried out. The major outcome of the effectiveness of the robot assistive therapy for the movement of ankle and functioning of gait is deduced. As the used protocols and treatment procedures vary, made comparative study complex or impracticable.

CONCLUSION

Robo-rehabilitation possesses an ability to provide unified therapy protocols with greater ease in comparison to conventional therapies. They continuously prove to be irreplaceable assistant devices when it comes to providing excellent treatment in terms of improvement from this study. Though many mechatronic devices are available but the devices for treatment of early stage rehabilitation of stroke patients is very limited.