Bidirectional Tuning of the AFO Stiffness

NCT ID: NCT06412055

Last Updated: 2025-02-05

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: NA
• Total Enrollment: 10 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2024-05-15
• Study Completion Date: 2025-02-01

Brief Summary

The goal of this pilot study with a pre-post design is to investigate the effects of separate individualization of the AFO stiffness towards plantar- and dorsiflexion in a spring-hinged AFO on walking compared to a spring-like AFO (3 types) having the same stiffness in both directions.

People with a neuromuscular disease or nerve injury causing at least plantarflexor weakness (determined as the inability to perform 3 single heel rises), with an indication for or using an AFO, will be fitted with a new, custom-made spring-hinged AFO with the NEURO SWING® system ankle joint (Fior& Gentz, Lüneburg, Germany), of which the stiffness of ventral and dorsal compartment of this spring-hinged AFO will be individualized. For comparison, measurements will be performed with three different prefab spring-like AFOs with different stiffness levels (but which have a similar stiffness towards plantar and dorsiflexion), and the participants' current AFO if applicable, and shoes-only at baseline.

The main outcome parameters will be the maximal ankle plantarflexion angle, ankle angular velocity and knee flexion angle during the loading response, which will be measured using a 3D gait analysis. Secondary outcomes include other gait biomechanics, walking energy cost, walking speed, standing balance, perceived physical functioning and perceived walking ability.

Detailed Description

Many neuromuscular diseases cause weakness of the ankle dorsiflexors and plantarflexors, resulting in an altered gait pattern. In particular, weakness of the plantar flexors leads to a reduced walking ability as it hampers safety in both standing and walking. The primary treatment to improve walking ability and safety during standing and walking in dorsiflexor and/or plantarflexor weakness is the provision of ankle-foot orthoses (AFOs). To maximize treatment outcomes in case of lower leg weakness, the optimal AFO stiffness needs to be individually determined. Individual optimization of the stiffness can be performed with a spring-like AFO or with a spring-hinged AFO. With a spring-like AFO, the stiffness towards plantar- and dorsiflexion is similar, oftentimes resulting in a higher than necessary stiffness towards plantarflexion. An advantage of spring-hinged AFOs is that, unlike spring-like AFOs, the stiffness can be separately optimized in the directions of dorsiflexion and plantarflexion.

The objective of this pilot study is to evaluate the effects of separate individualization of the AFO stiffness towards plantar- and dorsiflexion in a spring-hinged AFO compared to three types of spring-like AFO having the same stiffness in both directions on gait biomechanics, walking energy cost, walking speed, and standing balance. Additionally, effects will be evaluated of the optimal spring-hinged AFO 6 weeks after delivery of the AFO on perceived physical functioning, walking ability and satisfaction in daily life compared to the participants' AFO used at baseline if applicable or walking with shoes-only.

In this pilot study with a pre-post design, people with a neuromuscular disease or nerve injury causing at least plantarflexor weakness with an indication for or using an AFO will be fitted with a new, custom-made spring-hinged AFO with the NEURO SWING® system ankle joint (Fior& Gentz, Lüneburg, Germany). The stiffness of ventral and dorsal compartment of this spring-hinged AFO will be individualized using a previously developed optimization algorithm. The spring-hinged AFO with optimal stiffness settings will be used at home for 6-weeks. For comparison, the investigators will test the direct effects of three different prefab spring-like AFOs with different stiffness levels (but which have a similar stiffness towards plantar and dorsiflexion) of 2.8, 1.4 and 0.6 Nm/degrees respectively in a randomized order, and the participants' current AFO if applicable, and shoes-only at baseline.

Conditions

Neuromuscular Disorders

Study Design

• Allocation Method: NA
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: TREATMENT
• Blinding Strategy: NONE

Study Groups

NEURO SWING AFO

Participants will be fitted with a new custom-made spring-hinged AFO with the NEURO SWING® system ankle joint. Following a previously developed algorithm, the stiffness will be individually selected from six different configurations tested during an optimization measurement directly after delivery of the new AFO. Thereafter, participants will use the optimized AFO with individualized stiffness at home for six weeks during the course of the study.

Group Type: EXPERIMENTAL

NEURO SWING AFO (Fior& Gentz, Lüneburg, Germany)

Intervention Type: DEVICE

stiffness-optimized custom-made spring-hinged AFO with the NEURO SWING® system ankle joint build in

WalkOn Reaction® (Ottobock, Duderstadt)

Intervention Type: DEVICE

comparator: prefab spring-like AFO without hinge with a predefined stiffness (2.8 Nm/degree).

Matrix Max2® (TruLife, Dublin, Ireland)

Intervention Type: DEVICE

comparator: prefab spring-like AFO without hinge with a predefined stiffness (1.4 Nm/degree)

Matrix® (TruLife, Dublin, Ireland)

Intervention Type: DEVICE

comparator: prefab spring-like AFO without hinge with a predefined stiffness (0.6 Nm/degree)

Interventions

NEURO SWING AFO (Fior& Gentz, Lüneburg, Germany)

stiffness-optimized custom-made spring-hinged AFO with the NEURO SWING® system ankle joint build in

Intervention Type: DEVICE

WalkOn Reaction® (Ottobock, Duderstadt)

comparator: prefab spring-like AFO without hinge with a predefined stiffness (2.8 Nm/degree).

Intervention Type: DEVICE

Matrix Max2® (TruLife, Dublin, Ireland)

comparator: prefab spring-like AFO without hinge with a predefined stiffness (1.4 Nm/degree)

Intervention Type: DEVICE

Matrix® (TruLife, Dublin, Ireland)

comparator: prefab spring-like AFO without hinge with a predefined stiffness (0.6 Nm/degree)

Intervention Type: DEVICE

Eligibility Criteria

Inclusion Criteria

1. Age 18 years or older;

2. Presence of plantar flexor weakness in at least one leg, determined as a score lower than 5 on the manual muscle testing scale (Medical Research Council- MRC) and/or inability to perform three single heel rises, with or without dorsiflexion weakness;

3. Indicated for or using an AFO;

4. Ability to walk 6-minutes consecutively (with assistive device, if necessary).

Exclusion Criteria

1. When wearing the AFO, not able to walk short bouts of 10m without walking aids, such as a walker;

2. Foot deformities that do not fit in prefab spring-like AFOs;

3. Weakness of the knee extensor muscles, for which a knee-ankle-foot orthosis is indicated.

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

FIOR & GENTZ

UNKNOWN

Sponsor Role: collaborator

Academisch Medisch Centrum - Universiteit van Amsterdam (AMC-UvA)

OTHER

Sponsor Role: lead

Responsible Party

Merel Brehm

Principal Investigator

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Frans Nollet, MD PhD

Role: STUDY_DIRECTOR

Amsterdam UMC, location AMC

Locations

Department of rehabilitation medicine Amsterdam UMC, location AMC

Amsterdam, , Netherlands

Site Status: RECRUITING

Countries

Netherlands

Central Contacts

Merel-Anne Brehm, PhD

Role: CONTACT

m.a.brehm@amsterdamumc.nl

+ 3120 5664049

Elza van Duijnhoven

Role: CONTACT

e.vanduijnhoven@amsterdamumc.nl

+3120 5666915

Facility Contacts

Merel Brehm, PhD

Role: primary

m.a.brehm@amsterdamumc.nl

+ 31 20 5663669

Other Identifiers

NL85684.018.23

Identifier Type: -

Identifier Source: org_study_id