Articulated Custom Ankle-Foot Orthosis with Segmented Hinges
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Solution Overview
Problem
Conventional ankle-foot orthoses (AFOs) are cumbersome, expensive, and do not fit in normal-sized shoes, failing to provide adequate medial and lateral stabilization while allowing for dorsal and plantar flexion, which limits mobility and comfort for patients with ankle and foot conditions.
Innovation Solution
An articulated custom AFO system with a padded, lined, and covered design that includes calf and foot stiffeners, hinges, and adjustable tighteners, allowing for normal shoe wear and enhanced mobility through dorsal and plantar ankle flexion, using materials like thermoplastic foam and leather for comfort and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional braces are used to stabilize the ankle area, then medial and lateral stability is achieved, but the braces become large, thick, cumbersome, and do not fit in normal-sized shoes
Solution Approach 1:
The AFO is divided into separate functional components: a foot portion, a calf portion, hinge means connecting them, stiffener means in each portion, and lining means covering the stiffeners. This segmentation allows each component to be optimized independently, reducing overall bulk while maintaining stability function.
Solution Approach 2:
The patent uses thin, flexible lining means (outer lining, inner lining, and tongue) that cover the stiffener means. These flexible layers provide the necessary coverage and comfort without adding significant thickness, enabling the device to fit within normal shoe volumes while maintaining ankle stability.
2Reliability
If conventional braces are used to stabilize the ankle, then joint stability is improved, but the braces become expensive and require specialized shoe modifications
Solution Approach 1:
By segmenting the AFO into modular components (foot portion, calf portion, hinge means, stiffener means, lining means), the device can be manufactured using standard components and assembled through conventional processes, reducing manufacturing complexity and cost while maintaining joint stability.
Solution Approach 2:
The articulated design with hinge means allows the device to perform multiple functions: providing medial and lateral stability while simultaneously permitting controlled dorsal and plantar flexion. This multi-functionality is achieved through a unified structure that can be manufactured using conventional processes.
3Ease of operation
If a hinge is placed in the AFO to permit dorsal and plantar flexion, then normal walking motion is enabled, but the hinge may snag clothing and other objects
Solution Approach 1:
The hinge means is covered by flexible lining means including an outer lining, inner lining, and tongue that extend over the hinge area. This coverage eliminates protruding hinge components that could snag clothing, while the flexible nature of the lining allows the hinge to move freely for normal ankle flexion during walking.
Solution Approach 2:
The lining means acts as an intermediary layer between the mechanical hinge and the external environment (clothing, objects). This intermediate covering protects against snagging while maintaining the hinge's functional movement capability.
4Ease of manufacture
If off-the-shelf ankle braces are used, then cost is reduced, but they do not provide adequate support and chafe sensitive areas
Solution Approach 1:
The AFO is segmented into customizable components that can be configured to match individual patient anatomy and support requirements. This modular approach allows adequate support to be achieved without the high cost of fully custom-molded devices, as standard components can be assembled to meet specific medical needs.
Solution Approach 2:
The flexible lining means (outer lining, inner lining, tongue) are designed to conform to individual patient anatomy, preventing chafing of sensitive areas. These adaptable covering layers can be customized to fit unique foot shapes while maintaining adequate support at a lower cost than rigid custom braces.
Data Source
AI summary
A custom articulated ankle-foot orthosis (AFO) system is disclosed that is formed on a cast of the wearer's foot. It has an adjustably tightenable calf section hingedly connected to an adjustably tightenable foot section. It is made of thermally formable plastic sheet, is lined inside and outside, and is padded inside. The brace permits dorsal/plantar flexion while supporting the ankle against supination and pronation. The apparatus and methods of manufacture are disclosed.