Designing a passive dynamic SLS-3D printable ankle-foot orthosis

An ankle-foot orthosis (AFO) is a medical aid that helps individuals with deficient walking patterns achieve a more natural gait. There are various types of AFOs prescribed for different reasons. This thesis specifically focuses on passive dynamic ankle-foot orthoses (PD-AFOs) and even within that branch a very specific type: the carbon dorsal...

Interacting effects of AFO stiffness, neutral angle and footplate stiffness on gait in case of plantarflexor weakness: A predictive simulation study

To maximize effects of dorsal leaf ankle foot orthoses (AFOs) on gait in people with bilateral plantarflexor weakness, the AFO properties should be matched to the individual. However, how AFO properties interact regarding their effect on gait function is unknown. We studied the interaction of AFO bending stiffness with neutral angle and...

Predicting the effects of ankle-foot orthoses on the gait of patients with calf muscle weakness: A predictive forward dynamics simulation study

Various neuromuscular disorders such as spinal cord injury, Charcot-Marie-Tooth disease and poliomyelitis lead to calf muscle weakness, which limits the patient's ability to propel their body forward during gait. Their abnormal gait pattern is characterized by increased ankle dorsiflexion, excessive knee flexion during stance and reduced ankle...

Design, fabrication and validation of an ankle-foot orthosis simulator system to optimize mechanical characteristics of AFOs for humans with impaired locomotion

The muscles around the ankle (calf and dorsal flexors) are essential for performing activities in daily life, like walking. Neurological and muscular pathologies, such as stroke, cerebral palsy, spinal cord injury, muscle atrophy and post-polio syndrome, affect the ability of voluntary muscle control and/or muscle strength of such muscles. This...

Application of mechanical metamaterials in a parametric, 3D printed ankle foot orthosis

During this project the possibilities of enriching the functionality of an Ankle Foot Orthosis (AFO) by implementing mechanical metamaterials are researched. The project is executed for Buchrnhornen, a company based in Eindhoven which has over 70 years of experience in manufacturing orthopaedic shoes and orthosis in a traditional way. Mechanical...

Description of orthotic properties and effect evaluation of ankle-foot orthoses in non-spastic calf muscle weakness

Objective: To describe the orthotic properties and evaluate the effects of ankle-foot orthoses for calf muscle weakness in persons with non-spastic neuromuscular disorders compared with shoes-only. Design: Cross-sectional study. Subjects: Thirty-four persons who used ankle-foot orthoses for non-spastic calf muscle weakness. Methods: The...

Stiffness-Optimized Ankle-Foot Orthoses Improve Walking Energy Cost Compared to Conventional Orthoses in Neuromuscular Disorders: A Prospective Uncontrolled Intervention Study

In persons with calf muscle weakness, walking energy cost is commonly increased due to persistent knee flexion and a diminished push-off. Provided ankle-foot orthoses (AFOs) usually lower walking energy cost. To maximize the reduction in energy cost, AFO bending stiffness should be individually optimized, but this is not common practice....

Ankle foot orthoses in cerebral palsy: Effects of ankle stiffness on trunk kinematics, gait stability and energy cost of walking

In children with cerebral palsy (CP), rigid ventral shell ankle-foot orthoses (vAFOs) are often prescribed to reduce excessive knee flexion in stance and lower the energy cost of walking (ECW). However, how vAFOs affect ECW is a complex issue, as vAFOs may have an impact on lower limb biomechanics, upper body movements, and balance. Besides,...

Development of a 3D printed patient specific Ankle Foot Orthosis

Patients diagnosed with drop foot syndrome experience difficulties creating enough clearance during walking, resulting in stumbling over very small obstacles. An Ankle Foot Orthosis is an orthopaedic aid which limits the plantar flexion of the foot, providing a safe walking gait for the patient. Currently, these AFOs are vacuum formed over a...

Modifying ankle foot orthosis stiffness in patients with calf muscle weakness: gait responses on group and individual level

BACKGROUND: To improve gait, persons with calf muscle weakness can be provided with a dorsal leaf spring ankle foot orthosis (DLS-AFO). These AFOs can store energy during stance and return this energy during push-off, which, in turn, reduces walking energy cost. Simulations indicate that the effect of the DLS-AFO on walking energy cost and...

Design of an assistive cycling ankle-foot orthosis for Charcot-Marie-Tooth patients

This master thesis elaborates on the development of a assistive cycling ankle-foot orthosis for Charcot-Marie-Tooth patients. Study the influence of assistive torque on the kinematic analysis of the knee and ankle joints of a CMT patient on an ergometer bike.

Development of an ankle-foot orthosis that provides support for flaccid paretic plantarflexor and dorsiflexor muscles

ADJUST, a novel ankle-foot orthosis (AFO) that we have developed, allows the ankle a normal range of motion (ROM) while providing support for flaccid ankle-muscle paresis. It consists of two leaf-spring hinges that independently control plantarflexion and dorsiflexion stiffness. To evaluate whether ADJUST meets the minimum mechanical...

Design and evaluation of a stiffness compensating ankle-foot orthosis

This study proposes an ankle-foot orthosis (AFO) based on a novel concept to compensate increased ankle joint stiffness by adding negative stiffness to the joint. The negative stiffness working principle is a mechanism consisting of a spring generating force around a rotation axis, with a variable moment arm. The spring force is decreasing, when...