Constructing an Ankle Foot Orthosis for Eight Year Old Children with Spastic Cerebral Palsy
Abstract/Contents
- Abstract
- Cerebral palsy (CP) is one of the most common motor disorders in children in the United States, with 3 out of every 1000 8-year-old children diagnosed with the condition each year. Children with CP lack the musculoskeletal integrity to maintain a proper gait pattern. A healthy gait cycle consists of a “stance phase” where the foot hits and pushes off the ground into a “swing phase” where the foot leaves the ground and clears through the air. Often the stance phase of their gait cycle will break down into “flexed knee gait,” where the ankle exhibits significant excess dorsiflexion that results in the knee being bent, or “flexed." During the swing phase, this lack of musculoskeletal integrity allows the foot to experience excess plantarflexion. An Ankle Foot Orthosis is an assistive device built with the intention of supporting the ankle and foot to help keep it aligned during the gait cycle. Current AFO solutions on the market do not adequately address both of these gait abnormalities, and these devices are often bulky and cumbersome to wear. Thus, our team set out to design and build an AFO for 8-year old children with CP that will support their foot and ankle against excess dorsiflexion in stance and plantarflexion in swing. We also strove to make a durable device with a positive appearance. Our team analyzed the forces and moments acting on the foot and ankle during each part of the gait to find the forces that the AFO needs to oppose to stabilize the foot. Using Generative Design in Autodesk Fusion 360, we designed an AFO, made from Carbon Fiber, that provides sufficient support to withstand the loads involved in flexed-knee gait and is easy to take on and off while having a mass of 0.109 kilograms and a maximum thickness of 3 mm. The loads include 450 N on the shin plate due to excessive dorsiflexion and 7.8 N on the foot plate during foot drop. The design methodology was validated with parts made from Nylon PA 12. Using this geometry, we validated the carbon fiber design through testing against our load requirements for real world use. We plan to provide our design to Dr. Jessica Rose for future clinical work.
Description
| Type of resource | text |
|---|---|
| Date created | 2021 |
Creators/Contributors
| Author | Huerta, Bryce |
|---|---|
| Author | Chen, Sarah |
| Author | Gomez, Lizbeth |
| Author | Orozco, Daniela |
| Primary advisor | Rose, Jessica |
| Primary advisor | Schadl, Kornél |
| Sponsor | Stanford Department of Orthopaedics |
| Advisor | Wood, Jeffrey |
| Advisor | Traylor, Amelia |
Subjects
| Subject | Ankle-Foot Orthosis |
|---|---|
| Subject | AFO |
| Subject | Cerebral Palsy |
| Subject | CP |
| Subject | Mechanical engineering |
| Subject | Stanford Department of Orthopaedics |
| Genre | Student project report |
Bibliographic information
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- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
Preferred citation
- Preferred Citation
- Huerta, Bryce; Chen, Sarah; Gomez, Lizbeth; Orozco, Daniela. (2021). Constructing an Ankle Foot Orthosis for Eight Year Old Children with Spastic Cerebral Palsy. Stanford Digital Repository. Available at: https://purl.stanford.edu/dn232ht1727
Collection
ME170 Mechanical Engineering Design
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