AAOP State-of-the-Science Evidence Report: The Effect of Ankle-Foot Orthoses on Balance—A Systematic Review

Effects of carbon versus plastic ankle foot orthoses on gait outcomes and energy cost in patients with chronic stroke

OBJECTIVE

To compare the walking performances of hemiplegic subjects with chronic stroke under 3 conditions: with a new standard carbon fibre ankle foot orthosis (C-AFO), with a personal custom-made plastic AFO (P-AFO), and without any orthosis (No-AFO).

DESIGN

Randomized, controlled crossover design.

PATIENTS

Fifteen chronic patients with stroke (3 women  and 12 men, 59 [10] years, 13 [15] years since injury).

METHODS

Patients performed 3 randomized sessions (with C-AFO, P-AFO, no-AFO), consisting of a 6-min walk test (6MWT) with VO2 measurement and a clinical gait analysis. Energy cost (Cw), walking speed, spatio-temporal, kinetic, and kinematic variables were measured.

RESULTS

No significant differences were found between the C-AFO and P-AFO conditions. Distance and walking speed in the 6MWT increased by 12% and 10% (p < 0.001) and stride width decreased by -8.7% and -13% (p < 0.0001) with P-AFO and C-AFO compared with the No-AFO condition. Cw decreased by 15% (p < 0.002), stride length increased by 10% (p < 0.01), step length on affected leg increased by 8% (p < 0.01), step length on contralateral leg by 13% (p < 0.01), and swing time on the contralateral leg increased by 6% (p < 0.01) with both AFO compared with the No-AFO condition.

CONCLUSION

The use of an off-the-shelf composite AFO (after a short habituation period) in patients with chronic stroke immediately improved energy cost and gait outcomes to the same extent as their usual custom-made AFO.

Effect of foot orthoses on balance among individuals with flatfoot: A systematic review and meta-analysis

Individuals with flatfoot have impaired proprioception owing to ligament laxity and impaired tendons, which can result in poor balance. Foot orthoses (FOs) have been reported to stimulate plantar mechanical receptors and are used to manage foot overpronation in individuals with flatfoot. However, the results of the use of FOs to improve balance are inconsistent. In this systematic review and meta-analysis, we aimed to identify and investigate the effects of FOs on balance in individuals with flatfoot. Electronic databases were searched for articles published before March 2023. Peer-reviewed journal studies that included adult participants with flexible flatfoot and reported the effects of FOs on balance were included and classified based on the study design: randomized control trials (RCT) and non-RCTs. Four RCT studies were retained, and their methodological quality was assessed (mean, 63.2%; range 47.3%-73.1%: high), as were three non-RCT studies (mean, 54.1%; range, 42.1%-68.4%: high). Meta-analysis was performed by calculating the effect size using the standardized mean differences between the control and FO conditions. Transverse-arch insoles immediately improved static balance after use. However, no immediate significant effect was found for medial archsupport FOs, cuboid-posting FOs, or University of California Berkeley Laboratory FOs during the study period (2-5 weeks) when compared with the controls. The transverse-arch insole is the most effective FO feature for improving static balance. However, the high heterogeneity between study protocols contributes to the lack of evidence for the effects of FO on balance in people with flatfoot.

Orthotic intervention following stroke: a survey of physiotherapist, occupational therapist and orthotist practice and views in the UK

Background/Aims Orthoses are often used to promote mobility and rehabilitation for patients in the UK after a stroke. The perspective of stroke therapists in the UK is an important factor determining current practice and orthotic provision. The purpose of this study was to investigate the views of orthotists, physiotherapists and occupational therapists on the delivery mechanisms and relationships that influence orthoses intervention and provision for patients with stroke in the UK.

Methods A UK-based online survey was conducted. Participants were stroke therapy clinicians within acute and community settings, recruited through their membership of the British Association of Prosthetists and Orthotists, the Association of Chartered Physiotherapists Interested in Neurology, and the Royal Collage of Occupational Therapists—Specialist Section for Neurological Practice. Data were analysed using descriptive statistics and content analysis.

Results A total of 305 questionnaires were completed (64 orthotists, 131 physiotherapists, 110 occupational therapists). Some 67% (n=190) of respondents identified the optimal timing for initial orthotic assessment as within the first days following a stroke or before discharge from hospital. Waiting times and operational barriers to orthoses provision were perceived to have a negative impact on patients’ rehabilitation. A closer working relationship between orthotists and the stroke rehabilitation team is desirable.

Conclusions The survey found that the use of orthoses and orthotic specialist input are perceived to play an important role within the stroke rehabilitation pathway. Further evaluative research is warranted to explore the optimal timing and benefits, and the orthotist's role within the stroke rehabilitation team.

Impact of an ankle foot orthosis on reactive stepping in young adults

BACKGROUND

Ankle-foot orthoses (AFOs) have been shown to improve gait and static balance in individuals with lower extremity weakness and instability. However, the effects of AFOs on dynamic balance reactions including reactive stepping responses are not well known. Therefore, the purpose of this study was to determine the effects of an AFO on reactive stepping responses in healthy young adults.

RESEARCH QUESTION

Does an AFO alter reactive stepping responses in healthy young adults?

METHODS

Twenty healthy young adults completed 10 reactive stepping trials using a lean-and-release system for each of three AFO conditions: 1) no AFO, 2) AFO on left leg and 3) AFO on right leg. Trials were recorded using 3D motion capture and force plates. Stepping limb preference and temporal, spatial, and kinematic variables were measured. Differences between conditions were determined by a one-way ANOVA with a Tukey post-hoc.

RESULTS

With no AFO, participants demonstrated a preference for stepping with the right leg, 7.0 ± 3.9 of 10 trials. With an AFO on the right leg, this preference decreased to 5.7 ± 4.4 (p = 0.03). With an AFO on the left leg, this preference increased to 8.1 ± 3.3 (p = 0.03). Reaction times were not significantly different between conditions, but participants took a significantly shorter reactive step with the leg wearing the AFO. Peak ankle, knee, and hip joint angles were significantly less with the AFO on the stepping limb compared to the stance limb.

SIGNIFICANCE

This study shows that AFO use can influence reactive stepping limb preference and stepping limb kinematics in healthy young adults. These results can inform future research on AFO users with gait impairments. These finding may also be helpful in developing interventions to address the specific effects of an AFO on reactive stepping responses.

Optimized Design of a Variable Viscosity Link for Robotic AFO

Herein we present the development of a novel Ankle Foot Orthosis for gait support of people with foot-drop symptoms. The developed AFO uses an elastic link mechanism to brake the ankle joint during initial contact, thus mitigating foot-slap, and an integrated energy store-and-release mechanism to support toe lift in the swing phase, thus mitigating toe-drag. This paper presents improvements in the braking-holding power of the elastic link mechanism over its previous version, the torque-angle characteristics of the developed AFO with the renewed elastic link, and a pilot test with one person with foot-drop symptoms to verify the proposed functions of the developed AFO.

Effectiveness of Daily Use of Bilateral Custom-Made Ankle-Foot Orthoses on Balance, Fear of Falling, and Physical Activity in Older Adults: A Randomized Controlled Trial

BACKGROUND

Foot problems are prevalent in older adults, which may increase the risk and concern for falls. Ankle-foot orthoses (AFO) have been shown to be effective in the stabilization of lower extremities, but their long-term effectiveness in improving balance and their potential to encourage older adults to become more physically active are still debated.

OBJECTIVE

This randomized controlled trial investigated the effectiveness of daily use of a custom-made AFO on balance, fear of falling, and physical activity in older adults.

STUDY DESIGN

Forty-four older adults with concern about or at risk for falling were randomly allocated to either the control group (CG; 77.3% female, age 75.6 ± 6.5 years, BMI 29.3 ± 6.4) or the intervention group (IG; 63.6% female, age 73.7 ± 6.3 years, BMI = 27.8 ± 4.8). The IG received walking shoes and bilateral custom-made AFO. The CG received only walking shoes. At the baseline and 6-month follow-ups, balance and physical activity were assessed using validated wearable instrumentation and fear of falling was assessed using the Fall Efficacy Scale-International (FES-I). Adherence and acceptability toward wearing the AFO were assessed using self-reported questionnaires at the 6-month follow-up.

RESULTS

No significant between-group difference was observed at baseline (p = 0.144-0.882). Compared to baseline and the CG, hip, ankle, and center-of-mass (COM) sways were significantly reduced at the 6-month follow-up in the IG while standing with the feet together during the eyes-open condition (p = 0.005-0.040). Within the IG, the FES-I was reduced significantly (p = 0.036) and there was an increasing trend in the number of walking bouts with a medium effect size (d = 0.52, p = 0.440) compared to baseline. However, there were no significant changes in FES-I and physical activity measures in the CG (p = 0.122-0.894). The reduction in COM sway in the IG was moderately correlated with adherence (r = -0.484, p = 0.047) and strongly correlated with baseline COM sway (r = -0.903, p < 0.001).

CONCLUSION

Results suggest that bilateral custom-made AFO plus walking shoes is effective in improving balance compared to walking shoes alone, and it significantly reduces the fear of falling, with a nonsignificant but noticeable positive trend in physical activity, compared to baseline. The results also suggest that older adults with poor balance at baseline and higher daily adherence to using the AFO will gain more benefit from the AFO intervention.

Shape Memory Ankle-Foot Orthoses

Electrically actuated ankle-foot orthoses (AFOs) were designed and prototyped using shape memory textile composites. Acrylic copolymers were synthesized as the matrix to demonstrate shape memory effects, whereas electrothermal fabrics were embedded to generate uniform heat as a trigger. Superior to conventional polymeric orthoses, shape memory AFOs (SM-AFOs) could be repeatedly programmed at least 20 times with stable shape fixity and recovery. Evidenced by clinical practice, SM-AFOs were effectively actuated at 10 V, allowing the correction of ankle angles with 10° plantarflexion. Ultimately, we envision a smart orthopedic system that can advance progressive rehabilitation with manipulation under safe and convenient conditions.

The effect of augmented somatosensory feedback on standing postural sway

Impaired balance resulting from reduced postural control occurs with aging and various medical conditions. Sensory input for balance control is provided by the visual, vestibular and somatosensory systems. Previous research suggests that increased proprioceptive feedback from various lower extremity devices improves balance. Mixed results have been reported with the use of orthoses such as ankle foot orthoses (AFOs). In this study, 20 healthy subjects wore footplates in their shoes or straps around their lower legs in order to imitate the somatosensory feedback produced by wearing AFOs, but without providing ankle restriction. Subjects' standing balance was assessed using force plates and computerized dynamic posturography (the sensory organization test-SOT) to determine if either the footplates or the lower-leg straps would affect standing balance. The results revealed no significant difference with the use of the footplates, however, wearing the straps resulted in reduced postural sway for conditions when visual cue deprivation was combined with manipulation of somatosensory or vestibular feedback. This effect was more pronounced in participants with the poorest baseline measures of balance. These findings suggest that lower extremity devices, such as AFOs, may augment somatosensory feedback that could improve balance during challenging sensory deprivation conditions, independent of orthotic support at the ankle.

Effects of ankle-foot orthoses on mediolateral foot-placement ability during post-stroke gait

BACKGROUND

Accurate and precise mediolateral foot placement is important for balance during gait, but is impaired post stroke. Mediolateral foot placement may be improved with ankle-foot orthosis use.

OBJECTIVE

The purpose of this study was to determine whether an ankle-foot orthosis improves mediolateral foot-placement ability during post-stroke ambulation.

STUDY DESIGN

Crossover trial with randomized order of conditions tested.

METHODS

The accuracy and precision of mediolateral foot placement was quantified while subjects targeted four different randomized step widths. Subjects were tested with and without their regular non-rigid ankle-foot orthosis in two separate visits (order randomized).

RESULTS

While ankle-foot orthosis use corrected foot and ankle alignment (i.e. significantly decreased mid-swing plantar flexion, p = 0.000), effects of ankle-foot orthosis use on hip hiking (p = 0.545), circumduction (p = 0.179), coronal plane hip range of motion (p = 0.06), and mediolateral foot-placement ability (p = 0.537) were not significant.

CONCLUSION

While ankle-foot orthosis-mediated equinovarus correction of the affected foot and ankle was not associated with improved biomechanics of walking (i.e. proximal ipsilateral hip kinematics or mediolateral foot-placement ability), it may affect other aspects of balance that were not tested in this study (e.g. proprioception, cerebellar, vestibular, and cognitive mechanisms).

CLINICAL RELEVANCE

Studies that investigate the effect of ankle-foot orthosis on gait can help advance stroke rehabilitation by documenting the specific gait benefits of ankle-foot orthosis use. In this study, we investigated the effect of ankle-foot orthosis use on mediolateral foot-placement ability, an aspect of gait important for maintaining balance.

Dorsiflexion assist orthosis reduces the physiological cost and mitigates deterioration in strength and balance associated with walking in people with multiple sclerosis

OBJECTIVE

To evaluate the effect of wearing a dorsiflexion assist orthosis (DAO) on walking distance, physiological cost, fatigue, and strength and balance measures after a modified 6-minute walk test (6MWT) in people with multiple sclerosis (MS).

DESIGN

Randomized crossover trial.

SETTING

Hospital Movement Laboratory.

PARTICIPANTS

People with moderate MS and Expanded Disability Status Scale score of 3.7±0.7 (N=34; 26 women).

INTERVENTIONS

Modified 6MWT with and without a DAO worn on the weaker leg.

MAIN OUTCOME MEASURES

Distance walked, perceived fatigue, and the physiological cost of walking were compared between walking conditions. Pre- and postwalk changes in knee extensor and ankle dorsiflexor isometric strength and standing postural sway with eyes open and closed were compared between walking conditions.

RESULTS

There were no differences in distance walked or perceived fatigue between the 2 walking conditions. However, there was a reduced physiological cost of walking (P<.05), a smaller reduction in knee extensor strength (P<.05), and a smaller increase in standing postural sway with eyes open (P<.01) after walking while wearing the DAO compared with walking without wearing the DAO.

CONCLUSIONS

Despite not increasing walking distance or reducing perceived fatigue, the DAO reduced the physiological cost of walking and maintained knee strength and standing balance, which may have important implications for physical rehabilitation in people with MS. Further trials are required to determine whether the beneficial effects of wearing a DAO found here are maintained for longer periods.

Selective Laser Sintered Versus Carbon Fiber Passive-Dynamic Ankle-Foot Orthoses: A Comparison of Patient Walking Performance

Selective laser sintering (SLS) is a well-suited additive manufacturing technique for generating subject-specific passive-dynamic ankle-foot orthoses (PD-AFOs). However, the mechanical properties of SLS PD-AFOs may differ from those of commonly prescribed carbon fiber (CF) PD-AFOs. Therefore, the goal of this study was to determine if biomechanical measures during gait differ between CF and stiffness-matched SLS PD-AFOs. Subject-specific SLS PD-AFOs were manufactured for ten subjects with unilateral lower-limb impairments. Minimal differences in gait performance occurred when subjects used the SLS versus CF PD-AFOs. These results support the use of SLS PD-AFOs to study the effects of altering design characteristics on gait performance.

The effect of ankle-foot orthoses on self-reported balance confidence in persons with chronic poststroke hemiplegia

BACKGROUND

One intervention often used to address physical impairments post stroke is an ankle-foot orthosis. Ankle-foot orthoses may improve walking speed, stride length, and gait pattern. However, effects on balance, crucial for safe ambulation, are thus far inconclusive. One aspect of balance shown to contribute to functional ability is self-efficacy. Self-efficacy, defined as the belief in one's ability to succeed in particular situations, has been shown to be more strongly associated with activity and participation (as defined by the International Classification of Functioning, Disability, and Health) than physical performance measures of gait or balance.

OBJECTIVES

We investigated whether self-efficacy, or balance confidence when referred to in the context of balance capabilities, is improved with ankle-foot orthosis use.

STUDY DESIGN

Repeated measures study design.

METHODS

Balance confidence was measured using the Activities-specific Balance Confidence Scale in 15 persons with chronic poststroke hemiplegia, with and without their regular ankle-foot orthosis.

RESULTS

Activities-specific Balance Confidence Scale scores were significantly higher (p ≤ 0.01) for the ankle-foot orthosis condition compared to no ankle-foot orthosis.

CONCLUSIONS

One mechanism by which ankle-foot orthosis use may influence balance is improved balance confidence. Future work should explore the specific mechanisms underlying this improvement in self-efficacy. Clinical relevance Self-efficacy may be an important factor to consider when evaluating functioning post stroke. Rehabilitative interventions that improve balance confidence may help restore participation and overall functioning in pathological populations, particularly in the fall-prone poststroke population. Study results provide evidence for improvements in balance confidence with ankle-foot orthosis use.

Influence of modified solid ankle-foot orthosis to be used with and without shoe on dynamic balance and gait characteristic in asymptomatic people

BACKGROUND

Ankle-foot orthoses are usually used in combination with footwear. Shoe design can have a significant effect on kinematics of the lower limb joints and line of action of the ground reaction force during walking. But, ankle-foot orthosis-footwear combination is not appropriate for indoor barefoot walking in some Asian cultures. In this study, we have modified a solid ankle-foot orthosis in order to set it in the same position as a solid ankle-foot orthosis-footwear combination.

OBJECTIVE

To investigate the effect of a modified solid ankle-foot orthosis; a solid ankle-foot orthosis which can be locked in different positions on gait and balance performance in comparison with a conventional solid ankle-foot orthosis, a common solid ankle-foot orthosis-shoe combination in asymptomatic adults.

STUDY DESIGN

Cross sectional.

METHODS

Two standard solid ankle-foot orthoses were manufactured with the ankle joint in neutral position. Then, one of these solid ankle-foot orthoses was modified in order to allow locking in a different alignment. Walk across, limit of stability, and sit-to-stand tests of the balance master system were performed while participants wore the modified solid ankle-foot orthosis aligned in 5°-7° anterior inclination without a shoe and a conventional solid ankle-foot orthosis-shoe combination.

RESULTS

There was no significant change in walking speed, step length, and step width with the conventional and modified solid ankle-foot orthoses. In addition, movement velocity and maximum excursion of the center of gravity during the limit of stability test were not different, although the maximal forward excursion of the center of gravity was longer when wearing the modified solid ankle-foot orthosis compared to the conventional solid ankle-foot orthosis-shoe combination (P = 0.000). Sway velocity of the center of gravity did not change during the sit-to-stand test.

CONCLUSION

The results demonstrated that the modified solid ankle-foot orthosis had the same effects as the conventional solid ankle-foot orthosis-shoe combination on the gait and balance performance of asymptomatic adults. Clinical relevance The findings of the present study can be used as the basis for further investigations on the efficacy of the modified solid ankle-foot orthoses in different neuromuscular populations in order to help people who do not wear shoes at home, as is the custom in some Asian cultures.