Single axis ankle-foot prosthesis with mechanically adjustable range of motion
Inventors
McNicholas, Sara Koehler • Nickel, Eric • FAIRHURST, Stuart • Keister, Justin • Hansen, Andrew H.
Assignees
United States Goverment Represented By Department Of Veterans Affairs AS • US Department of Veterans Affairs
Publication Number
US-11712351-B2
Publication Date
2023-08-01
Expiration Date
2039-06-14
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Abstract
An ankle prosthesis can have a base and an upper hinge component that is pivotably attached to the base about an axis. First and second biasing elements can bias the upper hinge component in first and second rotational directions, respectively. At least one selectively extendable and retractable locking element can extend from one of the base and the upper hinge component and engage the other of the base and the upper hinge component to limit the pivotable movement of the upper hinge component.
Core Innovation
The invention describes an ankle prosthesis comprising a base and an upper hinge component pivotably attached about an axis. The prosthesis includes first and second biasing elements that bias the upper hinge component in opposite rotational directions toward a neutral position. Additionally, it features at least one selectively extendable and retractable locking element that extends from either the base or the upper hinge component and engages the other component to limit the pivotable movement of the upper hinge.
The locking element(s) can be selectively extended to engage a stop surface when the upper hinge is in the neutral position, thereby locking or limiting movement. When retracted, the locking element permits movement of the upper hinge component in one of the rotational directions from the neutral position. The prosthesis can include a second such locking element to control the range of motion in the opposite rotational direction, offering an adjustable range of motion around the neutral position.
Claims Coverage
The patent includes one independent claim with various dependent claims illustrating the inventive features of the ankle prosthesis design.
Selective extendable and retractable locking element for controlling pivotable movement
The ankle prosthesis comprises a base and an upper hinge component pivotably attached about an axis, with a first selectively extendable and retractable locking element extending from one component. When in the neutral position and the locking element is in a locking position, it engages the other component to limit movement.
Second locking element providing adjustable range of motion in opposite direction
A second selectively extendable and retractable locking element can also extend from one component and engage the other at the neutral position to lock movement in the opposite rotational direction, allowing selective retraction to permit movement.
Locking elements configured as adjustment screws within threaded holes engaging stop surfaces
The upper hinge defines first and second threaded holes housing the first and second screws that can advance to engage stop surfaces on the base, limiting the range of pivotable motion in respective rotational directions from the neutral position.
Opposite side placement of locking elements relative to the pivoting axis
The first and second locking elements are arranged on opposite sides of a vertical plane that includes the pivot axis, allowing independent control of motion directions.
Range indicators showing allowable ranges of motion
The prosthesis includes range indicators associated with the locking elements, which can be markings on an adjustment wrench, windows displaying screw positions with markings, gauges with pointers, spring-loaded ball detents, or sets of markings on the upper hinge to indicate the restricted range of motion.
Base structure including footplate and lower hinge non-rotatably attached
The base comprises a footplate and a lower hinge component that is non-rotatably attached to the footplate, forming the structural foundation for the upper hinge pivotally attached thereto.
Locking elements implemented as set screws
The first and second selectively extendable and retractable locking elements are implemented as set screws disposed in the threaded holes of the upper hinge component.
Locking elements permitting at least fifteen degrees rotation when retracted
The selective retraction of the locking elements permits at least fifteen degrees of rotational movement in their respective directions from the neutral position, with final range limited by engagement between the upper hinge and base.
Electronically controlled locking elements with linear actuators
In an alternate embodiment, the locking elements include pivotable platforms coupled to non-backdrivable linear actuators positioned between the base and platform. These actuators rotationally position the platforms relative to stop surfaces on the upper hinge component to limit movement, controllable by a microcontroller with sensors and possibly a remote device.
The claims cover an ankle prosthesis with a pivoting upper hinge component having selectively extendable and retractable locking elements on opposite sides, implemented as screws or actuated platforms, that engage stop surfaces to limit motion in opposing rotational directions. The range of motion is adjustable and indicated by various mechanical or electronic means, with the prosthesis built upon a base including a footplate and lower hinge.
Stated Advantages
Provides adjustable stability of the ankle prosthesis, particularly useful during initial rehabilitation after amputation.
Documented Applications
Use in prosthetic ankle-foot systems designed primarily for walking mobility.
Adjustable stability during rehabilitation phases after amputation.
Therapist-controlled adjustment of prosthesis range of motion using mechanical or electronic means.
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