Papers

2013

Optimising Ankle Foot Orthoses for children with Cerebral Palsy walking with excessive knee flexion to improve their mobility and participation; protocol of the AFO-CP study

Yvette L Kerkum, Jaap Harlaar, Annemieke I Buizer, Josien C van den Noort, Jules G Becher and Merel-Anne Brehm

Feb 2013 BCM Pediatrics

Abstract

Ankle-Foot-Orthoses with a ventral shell, also known as Floor Reaction Orthoses (FROs), are often used to reduce gait-related problems in children with spastic cerebral palsy (SCP), walking with excessive knee flexion. However, current evidence for the effectiveness (e.g. in terms of walking energy cost) of FROs is both limited and inconclusive. Much of this ambiguity may be due to a mismatch between the FRO ankle stiffness and the patient’s gait deviations. The primary aim of this study is to evaluate the effect of FROs optimised for ankle stiffness on the walking energy cost in children with SCP, compared to walking with shoes alone. In addition, effects on various secondary outcome measures will be evaluated in order to identify possible working mechanisms and potential predictors of FRO treatment success.

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2014

Defining the Mechanical Properties of a Spring-hinged Ankle Foot Orthosis to Assess its Potential Use in Children With Spastic Cerebral Palsy

Yvette L. Kerkum, Merel-Anne Brehm, Annemieke I. Buizer, Josien C. van den Noort, Jules G. Becher, and Jaap Harlaar

Dec 2014 Human Kinetics Journals

Abstract

A rigid ventral shelf ankle foot orthosis (AFO) may improve gait in children with spastic cerebral palsy (SCP) whose gait is characterized by excessive knee flexion in stance. However, these AFOs can also impede ankle range of motion (ROM) and thereby inhibit push-off power. A more spring-like AFO can enhance push-off and may potentially reduce walking energy cost. The recent development of an adjustable spring-hinged AFO now allows adjustment of AFO stiffness, enabling tuning toward optimal gait performance. This study aims to quantify the mechanical properties of this spring-hinged AFO for each of its springs and settings. Using an AFO stiffness tester, two AFO hinges and their accompanying springs were measured. The springs showed a stiffness range of 0.01−1.82 N·m·deg−1. The moment-threshold increased with increasing stiffness (1.13–12.1 N·m), while ROM decreased (4.91–16.5°). Energy was returned by all springs (11.5–116.3 J). These results suggest that the two stiffest available springs should improve joint kinematics and enhance push-off in children with SCP walking with excessive knee flexion.

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2015

Acclimatization of the gait pattern to wearing an ankle–foot orthosis in children with spastic cerebral palsy

Yvette L. Kerkum, Merel-Anne Brehm, Kim van Hutten, Josien C. van den Noort, Jaap Harlaar, Jules G. Becher and Annemieke I. Buizer

Jul 2015 Clinical Biomechanics

Abstract

Ankle–foot orthoses can be prescribed to improve gait in children with cerebral palsy. Before evaluating the effects of ankle–foot orthoses on gait, a period to adapt or acclimatize is usually applied. It is however unknown whether an acclimatization period is actually needed to reliably evaluate the effect of a new orthosis on gait. This study aimed to investigate whether specific gait parameters in children with cerebral palsy would change within an acclimatization period after being provided with new ankle–foot orthoses.

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The Effects of Varying Ankle Foot Orthosis Stiffness on Gait in Children with Spastic Cerebral Palsy Who Walk with Excessive Knee Flexion

Yvette L. Kerkum, Annemieke I. Buizer, Josien C. van den Noort, Jules G. Becher, Jaap Harlaar and Merel-Anne Brehm

Nov 2015 PLOS ONE

Abstract

Rigid Ankle-Foot Orthoses (AFOs) are commonly prescribed to counteract excessive knee flexion during the stance phase of gait in children with cerebral palsy (CP). While rigid AFOs may normalize knee kinematics and kinetics effectively, it has the disadvantage of impeding push-off power. A spring-like AFO may enhance push-off power, which may come at the cost of reducing the knee flexion less effectively. Optimizing this tradeoff between enhancing push-off power and normalizing knee flexion in stance is expected to maximize gait efficiency. This study investigated the effects of varying AFO stiffness on gait biomechanics and efficiency in children with CP who walk with excessive knee flexion in stance.

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2016

An individual approach for optimizing ankle-foot orthoses to improve mobility in children with spastic cerebral palsy walking with excessive knee flexion

Yvette L. Kerkum a,*, Jaap Harlaar a, Annemieke I. Buizer a, Josien C. van den Noort a,Jules G. Becher a, Merel-Anne Brehm

May 2016 GAIT & POSTURE

Abstract

Ankle-Foot Orthoses (AFOs) are commonly prescribed to promote gait in children with cerebral palsy (CP). The AFO prescription process is however largely dependent on clinical experience, resulting in confusing results regarding treatment efficacy. To maximize efficacy, the AFO's mechanical properties should be tuned to the patient's underlying impairments. This study aimed to investigate whether the efficacy of a ventral shell AFO (vAFO) to reduce knee flexion and walking energy cost could be improved by individually optimizing AFO stiffness in children with CP walking with excessive knee flexion. Secondarily, the effect of the optimized vAFO on daily walking activity was investigated.

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2017

How does a Personalized Rehabilitative Model in fluence the Functional Response of Different Ankle Foot Orthoses in a Cohort of Patients Affected by Neurological Gait Pattern?

Maurizio Falso, Eleonora Cattaneo, Elisa Foglia, Marco Zucchini and Franco Zucchini

Aug 2017 Journal of Novel Physiotherapy and Rehabilitation

Abstract

Orthoses need to support physiotherapy as well as surgical treatment. Related to patient’s rehabilitative goals and pathological gait pattern, orthotists have to produce an orthoses that using an adjustable ankle joint system with preloaded disc springs can store the energy brought in by the body weight and produce a tuning effect on patient’s gait and sense of balance. The purpose of this study was to establish how a personalized proprioceptive individualized rehabilitative treatment could influence the functional response of different AFOs (Ankle Foot Orthoses) in a cohort of patients affected by neurological gait pattern.

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The Categories of AFO and Its Effect on Patients With Foot Impair: A Systemic Review

Yong Feng and Yang Song

Nov 2017 Physical Activity and Health

Abstract

There are a lot of ailments that would lead to foot impair. For instance, cerebral palsy (CP), stroke, multiple sclerosis (MS), hemiplegia, duchenne muscular dystrophy (DMD) and so on. With the further deterioration of these diseases, gait would become imbalanced and then it may contribute to high risk of fall incidence. Thus, it is urgent to invent a tool to adjust the foot impair. Most of the previous studies had found that the ankle-foot orthoses (AFO) has a significant effect to overcome the foot impair. Studies that investigated the ankle-foot orthoses (AFO) and its effect on patients with foot impair are various and abundant. Nevertheless, there are a little studies that integrated the categories of AFO and its specific effect on patients with foot impair. It is important to integrate the categories of AFO and its specific effect on patients with foot impair because the previous studies had proved that different designs of AFO have different mechanical properties and these would affect outcomes in a way. The purpose of this paper is to review and integrate the published studies on the categories of AFO and its effect on patients with foot impair and thereby offer better guidelines and suggestions for prescriptions and future studies

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