Patent Application
20230301812
Many different devices have been utilized in the past to assist with lower extremity conditions that lead to weakness, abnormal gait, contracture, and joint deformity. One of these devices is an ankle foot orthosis (AFO), which helps provide support and assist in normalizing gait mechanics, balance and stability, and endurance and distance. AFOs normalize gait by providing support for joint segments of the foot, ankle and knee with stop motion or resistance. AFOs come in many different forms, material selections, trimlines, strap configurations and components to provide very specific functions to the patient.
As is well known, traditional AFOs typically combine multiple materials to achieve the necessary support functions, while also providing comfort and usability. That said, the selection configuration and characteristics of the various components involved greatly affect the way an AFO operates, and consequently need to be carefully considered when designing such products.
One particular concern with AFO design is the flexibility of the footplate. When the footplate is too flexible, the patient has decreased power at toe-off and it does not generate propulsion late in the stance cycle to achieve adequate step length on the contralateral swing limb. Footplate stiffness will provide various level of stability for the user, and thus should be carefully designed into the AFO.
To provide specific levels of stability and other functions, early braces (early AFOs) used a metal stirrup which is incorporated into a shoe. These braces, as generally illustrated in
As can be appreciated, it would be beneficial to have an orthosis that is more streamlined and user friendly that can be used in many different shoes rather than being attached to a specific shoe. Further, thermoplastic AFO designs provide additional support while increasing surface area on the limb, thus providing enhanced foot and ankle alignment control, and more comfort for the user. Further, the traditional AFO, as generally discussed above, does not provide support beyond creating a structured ankle joint. More specifically, the prior art AFO is not capable of providing any significant lateral support to the user. As such, an improved and more efficient AFO is clearly desirable.
An improved ankle foot orthosis (AFO) is achieved by incorporating a reinforced stirrup footplate into the design. The reinforced stirrup footplate is specifically configured to have desired levels of stiffness and is structured in a way simulate pushoff within a normal gait cycle. The additional stiffness below a user's foot, and support on either side of the user's heel also controls compensations in the transverse plane (in-toeing and out-toeing). This stirrup footplate is also configured to be easily incorporated into an AFO in a manner that provides significant levels of support, in multiple directions, thereby maximizing the functional benefit to the patient.
Further advantages and features of the various embodiments can be seen from reading the following description, in conjunction with the drawings in which:
To provide additional levels of stability for users of an AFO, a simplified stirrup footplate is being provided which can be formed into the plantar surface of an AFO to provide additional levels of stability in numerous directions. A primary goal of this simplified stirrup footplate is to provide stability along the length of the footplate, while also providing lateral or torsional stability for the user's foot while in use. As will be described in further detail below, the stirrup foot plate is an accessory component that is fabricated and bonded to the plantar surface of a custom fabricated thermal plastic AFO.
A rigid/reinforced foot plate is often indicated for patients that have sagittal plane deficits that include crouch gait, early heel off, fall-off at the knee at mid-stance, anterior center of mass, toe walking, plantarflexion weakness, and observed short step length. AFO stiffness provides additional control, mid-stance and terminal stance and encourages knee extension by resisting ankle dorsiflexion. The increased stiffness in the toe plate creates a ground reaction force that encourages knee extension, propulsion at push-off and contralateral increase step length.
The various embodiments of the stirrup footplate discussed in further detail below includes lateral projections that are located at approximately malleolar center while viewing in the sagittal plane. They extend proximally just distal to the malleolus mediately and laterally. These lateral extensions increase transverse plane and coronal plane stiffness, preventing commonly observed, external and internal foot projections (torsional rotation) and genuvalgum in the coronal plane.
Turning now to
As suggested above, it is contemplated that stirrup footplate 40 may be heat bonded to a thermoplastic portion of an AFO 60. In one embodiment, this bonding will occur during a vacuum forming process which will produce a unitary component having additional levels of support for a user's foot. The
It is generally contemplated that stirrup footplate 40 will be a formable plastic material, that can be easily formed into portion of AFO 60. That said, stirrup footplate 40 will be more rigid or stiff than material making up AFO 60, thereby providing specific levels of additional support for the portions of AFO 60 where this component is incorporated. Further, it is contemplated that various types of alternative materials could be used, but certain types of plastics are well suited for this purpose. Additionally, the thermoplastic material contemplated can also be combined with other components, such as padding and supporting straps, and other components used to form a completed AFO 60
As will be recognized, the stirrup footplate 40 reinforces (stiffens) the toe plate of AFO 60 and the lateral extensions 46, 48 on either side provide transverse (torsion) plane control. In its most general form, this stirrup footplate 40 is an addition to a lower extremity foot plate that provides additional features not previously possible. In most cases, it will be added to existing models of an AFO that are specifically tailored for a particular patient.
As suggested above, one application of the stirrup footplate 40 will allow an AFO 60 to be inserted into a shoe of the user. Generally, this is achievable by configuring the stirrup footplate 40 from a relatively thin portion of plastic material, which is easily formable to the bottom of an AFO's foot bed. One embodiment of AFO 60 is illustrated in
Referring now to
It is important to note that the stirrup footplate 40 described and illustrated above is formed from a type of plastic, so that it can be easily bonded to a thermoplastic AFO 60. Although it is an additional component, it will provide the ability to be easily combined with the thermoplastic AFO 60 in a manner that essentially creates a unitary component. By carefully selecting the material thickness (i.e., the thickness of the plastic material making up the AFO 60), the level of added support can be customized to meet the specific needs of a patient. Additionally, the type of material used can also be varied to meet desired treatment goals. It is contemplated that the stirrup can be formed from polypropylene, or carbon infused polycarbonate, although other alternatives may be possible. Further, stirrup footplate 40 can be manufactured in many different ways, including but not limited to injection molding, 3D printing, stamping, etc. Further, it is possible that stirrup footplate 40 can be integrally formed as a portion of AFO 60 itself, and may undergo trimming after it has been bonded to AFO 60 to allow for customized fittings.
To provide ambulatory therapy and necessary support for patients, AFO 60 is specifically designed to be insertable into a shoe. Referring now
The poly carbonate stirrup comes in various sizes and thicknesses to accommodate pediatric and adult patients and to provide various levels of support. Various embodiments can allow for the use of plastic materials that are 3/32″, ⅛″, 5/32″, 3/16″ thick. Clearly, this can vary depending upon the specific type of material used and the level of stiffness desired. Clearly, other thicknesses are possible. Also, it is expected that the stirrup footplate 40 may be offered in many different sizes and slightly different configurations so that different sizes of patients can be accommodated. In addition, the material to be used will effect stiffness and the level of support provided. In one example, various poly-carbon materials have been found to be effective. Other material may include polypropylene, or carbon infused polycarbonate.
Various embodiments of the invention have been described above for purposes of illustrating the details thereof and to enable one of ordinary skill in the art to make and use the invention. The details and features of the disclosed embodiment[s] are not intended to be limiting, as many variations and modifications will be readily apparent to those of skill in the art. Accordingly, the scope of the present disclosure is intended to be interpreted broadly and to include all variations and modifications coming within the scope and spirit of the appended claims and their legal equivalents.
| Number | Date | Country | |
|---|---|---|---|
| 63269798 | Mar 2022 | US |
