WO2015025191A1

WO2015025191A1 - Drop foot orthosis

Info

Publication number: WO2015025191A1
Application number: PCT/IB2013/056758
Authority: WO
Inventors: Massimiliano SOLIDORO
Original assignee: LA SANITARIA PARMENSE SNC DI RONCHINI LAURA & SOLIDORO MASSIMILIANO
Current assignee: LA SANITARIA PARMENSE SNC DI RONCHINI LAURA & SOLIDORO MASSIMILIANO
Priority date: 2013-08-20
Filing date: 2013-08-20
Publication date: 2015-02-26
Anticipated expiration: 2016-02-20

Abstract

The finding consists of an orthosis for foot drop, intended to control and stabilize the position of the foot of a user with reduced or absent control of the lifting function. The orthosis (1) comprises a shaped plantar insole (2), adapted to support in abutment at least the rear and median parts of the sole of the foot, and means (3) for locking the same insole (2) to the lower part of the leg of the user. The locking means (3) comprise a pair of flaps, respectively internal (4) and external (5), which are extended from opposite sides in the rear portion of the plantar insole (2) intended to support the heel, along a direction substantially perpendicular to that of the same insole (2), and have height such to affect the Achilles tendon on both sides up to being arranged in abutment against the immediately supramalleolar area.

Description

DROP FOOT ORTHOSIS

TITLE: Orthosis for foot drop.

DESCRIPTION

The present invention is situated in the technical field relative to the surgical medical aids for supporting dysfunctions or disabilities of the locomotor apparatus.

In particular, the invention regards an ankle-foot orthosis, intended to correct the dysfunction known as foot drop.

Foot drop is a pathological conditions of the lower limbs characterized by considerable difficulty or impossibility for a subject to lift the front part of his/her foot during deambulation. Such condition can be caused by various factors, such as the weakness of the anterolateral muscles of the leg, adapted for lifting and lowering the foot by means of the tibiotarsal joint (ankle), lesions that affect the aforesaid muscles, or neurological problems regarding the nerves assigned for controlling the same muscles.

The presence of this pathology leads the subject to drag the foot during walking or to have a so-called "steppage" gait, i.e. to lift the leg upward in order to not hit the ground with the tip of his/her foot. Even if not considered a severely disabling pathology, it is clear that it still involves significant inconvenience and limitations for those who suffer therefrom.

In order to control and make less evident and irritating the problems deriving from foot drop, particular orthoses are used, so-called A.F.O foot-leg tutors, which the patient applies when he must walk.

In general, an orthosis is an orthopedic aid that can carry out one or more functions: supporting, unloading, immobilizing, guiding, correcting the posture or correctly positioning a specific part of the human body, such as a limb or a part thereof.

With regard to the correction of the foot drop, orthoses are known of various types, which differ from each other due to construction structure or for the materials used.

By way of example, a first type of known orthosis provides for a structure made of plastic material, e.g. polyethylene or polypropylene, which comprises an insole adapted to fully or partially supporting the sole of the foot. From the rear side of the insole, an upright is extended that is substantially perpendicular, enclosing the heel, winding around the Achilles tendon and extending for the entire surface of the calf. Outlets are possibly provided in the upright for the heel and for the rear zone of the calf.

At the upper end of the upright, a horizontal band of soft fabric is provided, intended to be wound around the calf in order to stabilize the position of the orthosis. The closure of the band, usually of Velcro type, is adjustable in order to be adapted to the circumference of the calf. Since the coupling between the insole and the uprights is rigid, or has minimal elastic behavior, the foot is supported by the insole in a position perpendicular to the lower part of the foot. An orthosis variant of the type described above is made of leather, in order to obtain a more natural sensation of contact with the skin.

The conventional orthoses described above have various drawbacks. Firstly, they are rather bulky and do not allow wearers to conceal them from their placement on the lower part of the leg; consequently, the problem associated with the orthosis also becomes evident. This is rather limiting and often causes embarrassment, especially in the summer or for women who wish to wear skirts.

The winding structure of the upright is also hard to adapt to the anatomy of the lower part of the leg of the single user, due to the even considerable conformation differences between different subjects. For this reason, there are also frequent problems due to the excessive pressure exerted by the orthosis in some contact zone, which produces reddening/rashes and soreness of the affected part.

For some orthosis models, it is advised a manual adaptation operation of the upright on the calf, to be executed after having warmed the upright itself, for example by means of a hairdryer. Such operations are hard to execute and often obtain results of poor quality.

A different orthosis type provides for a gaiter made of elastic material, which is wound and fixed around the mid-upper part of the calf, a sleeve made of fabric wound around the foot at the metatarsal, and an adjustable belt that connects the gaiter with the sleeve, in order to maintain the foot in a position substantially perpendicular to the leg. In order to remedy the clear difficulty of putting on closed footwear, due to the presence of the sleeve, the latter can be substituted by a particular shoe adapted to clasp the adjustable belt.

In addition to the drawback constituted by the bulk and hence by the excessive visibility, this type of orthosis adds the drawback of requiring a special shoe, that is costly and not always adapted to the conformation of the foot.

The following documents are also known from the patent literature: US2006/0270958, DE8805663, DE9314920 and W098/34572.

US2006/0270958 discloses an orthosis that has two rear levers which :

- are extended to the calf

- the median zone of said levers is joined in order to abut against the Achilles tendon, as the same figure illustrates; this does not create leverage on the malleolar parts.

DE8805663 discloses an orthosis that has two levers which :

- enclose - including them - the malleoli laterally and the wings are laterally extended with the disadvantage of increasing the constraint of the malleolar articular fulcrum, i.e. the exact opposite of that undertaken up to now.

In addition, for both abovementioned cases, the insole must be extended for the entire length of the foot in order to operate efficiently, whereas in the current case it is ¾ the foot length.

One object of the invention is to propose an orthosis for foot drop capable of effectively opposing the collapse in plantarflexion of the foot that results practically invisible once worn, since the physiological levers of the foot are exploited by means of two uprights, acting as clamps, which are clasped to the supramalleolar zone.

Another object of the present invention is to propose an orthosis for controlling the foot drop capable of supporting the foot in a safe manner without adaptations being required for particular anatomic conformations of the user.

A further object of the invention is to propose an orthosis for foot drop which can be worn and removed in a quick and natural manner.

The abovementioned objects are all attained by the orthosis for controlling the foot drop, object of the present finding, which is characterized for that provided in the below-reported claims.

This and other characteristics will be clearer from the following description of several embodiments thereof, illustrated as a mere non-limiting example in the enclosed set of drawings.

Figure 1 : illustrates a ¾ front perspective view of a preferred embodiment of the orthosis, object of the invention;

Figure 2: illustrates a view of the rear side of the orthosis of figure 1;

Figure 3 : illustrates a perspective view of the orthosis of the preceding figures fit on a foot of a user;

Figure 4: illustrates a side view of a step of introducing the orthosis of figure 1 in a shoe;

Figure 5: illustrates a side view of the same orthosis once introduced in the shoe.

With particular reference to figure 1, an orthosis for foot drop is indicated with the reference number 1; in other words, this is an orthosis intended to control and stabilize the foot of a user with limited or absent control of the lifting function of the foot in a position in which it is substantially perpendicular to the axis of the lower part of the leg.

For this purpose, the orthosis 1 comprises a plantar insole 2, shaped according to the form of the sole of the user's foot, from the heel to the forefoot, or at least of the rear and median parts thereof.

The plantar insole 2 is extended and covers, once worn, ¾ of the surface of the foot that it supports.

As a function of the severity of the user's dysfunction, the irregularities in the conformation of his/her foot and the needs of the user himself/herself, the insole 2 can be provided with a shape based on standard physiological characteristics, in different sizes as a function of the size of the foot, or it can be custom- produced starting from a cast of the user's foot.

From the rear side of the plantar insole 2, means 3 extend for locking the insole 2 itself to the lower part of the user's leg. According to the invention, such means are constituted by a pair of flaps, respectively internal 4 and external 5, which are extended from opposite sides in the rear portion of the insole 2, i.e. that intended to support the heel, along a direction substantially perpendicular to the insole 2 itself (see also figure 2).

Each malleolar clamp or internal 4 and external 5 flap have height such to affect the Achilles tendon of the user on both sides, and to be arranged in abutment against the immediately supramalleolar zones thereof (figure 3). For such purpose, the flaps 4,5 are shaped in a manner so as to be perfectly adapted to the line of the rear part of the ankle, and are obtained diverging in the direction of the front part of the insole 2.

Basically, once the prosthesis is worn, the flaps 4, 5 act as clamps adapted to press and clasp the supramalleolar zone.

The plantar insole 2 and the internal 4 and external 5 flaps are conveniently made in a single body. In order to correctly carry out its function, the orthosis 1 is made with a material equipped with rigidity characteristics sufficient to make it substantially undeformable in normal use conditions, or at most with a minimal elastic response that tends to absorb and oppose undesired movements of the foot on the tibiotarsal joint.

A material that is particularly adapted for such purpose due to its mechanical characteristics, its lightness and versatility in molding the orthosis, has been found to be pre-impregnated carbon fiber.

In particular, the orthosis 1 is preferably obtained with a plurality of superimposed layers of pre-impregnated carbon fiber with thermosetting resins, in a suitable heatable mold. For the purpose of uniforming the mechanical characteristics of the orthosis in every direction, the successive fabric layers are preferably arranged crossed with an angle between the fibers of 45°.

As pre-impregnating substances, the following can be used for example: epoxy resins (preferable for the characteristics of resistance to the stresses and to the environmental conditions), phenol resins or other suitable industrial impregnating substances. The hardening of the resin and the stabilization of the orthosis are conveniently carried out in hot conditions in a suitably arranged mold.

In the internal face 4a, 5a of the malleolar clamps or internal 4 and external 5 flaps, contact bearings are provided, respectively 6,7, adapted to make the physiological point of abutment against the tibia and fibula more effective and the abutment of the same flaps more comfortable, and to avoid or reduce to a minimum the possibility of inflammation or soreness of the supramalleolar area.

The insole 2 can also have a slightly supinated arch, adapted to aid the stability of the foot with respect to the lateral movements.

Figures 3,4 and 5 illustrate two different ways of applying the orthosis 1 to the foot of the user.

In figure 3, the orthosis 1 is applied to the foot before this is introduced in the shoe. For this purpose, it is clear that the plantar insole 2 supports the foot from the heel to the forefoot at the metatarsal heads, and that the internal 4 and external 5 flaps arranged in abutment on both sides of the tendon and the malleolus, leaving the latter free in its movements, are opposed to the drop of the foot.

Figure 4 illustrates a first step for introducing the orthosis 1 in a shoe 8, whereas in figure 5 the orthosis 1 is completely inserted in the same shoe 8. At this point, the foot can be easily introduced in the shoe, and the orthosis 1 is immediately ready for use.

In each case, when the orthosis 1 is applied and the shoe 8 is worn by the user, the two points of abutment at the supramedullary level constituted by the upper part of the internal 4 and external 5 flaps provide the foot, by means of the insole 2, with a dorsally-directed thrust which opposes the collapse in plantarflexion, and allows maintaining the same foot lifted even when it is not situated in abutment against the ground. The above-described invention therefore allows advantageously opposing, in a simple and effective manner, the collapse in plantarflexion of the foot, also resulting practically invisible once worn.

Another advantage obtained by the orthosis according to the present invention is to obtain a safe and comfortable support for the foot without requiring adaptations for particular anatomical conformations of the user, such as the circumference of the calf, or systems for fixing the orthosis itself to the user's leg.

Claims

C LAI M S

1. Orthosis for foot drop, intended to control and stabilize the position of the foot of a user with reduced or zero control of the lifting function of the same foot, of the type comprising a plantar insole (2) shaped with length such to be extended, once worn for ¾ the length of the foot; the insole (2) adapted to support in abutment at least the rear and median parts of the sole of said foot, and means (3) for locking said plantar insole (2) to the lower part of the user's leg, said orthosis (1) being characterized in that said locking means (3) comprise a pair of flaps, respectively internal (4) and external (5), which are extended from opposite sides in the rear portion of said plantar insole (2) intended to support the heel, along a direction substantially perpendicular to that of the same abovementioned insole (2), and have height such to affect both sides up to the immediately supramalleolar area, the coupling between the abovementioned insole (2) and the flaps (4), (5) being rigid or with minimal elastic behaviour; said flaps (4, 5) operating, when mounted, as malleolar clamps which are clasped to the supramalleolar zone.

2. Orthosis, according to claim 1, characterized in that the abovementioned plantar insole (2) and flaps (4), (5) are obtained in a single body.

3. Orthosis, according to claim 1, characterized in that the abovementioned flaps (4), (5) are obtained diverging towards the front part of the abovementioned plantar insole (2).

4. Orthosis, according to claim 1, characterized in that in the internal face (4a), (5a) of the abovementioned flaps (4), (5), contact bearings (6), (7) are provided that are adapted to make the abutment of said flaps (4), (5) more comfortable.

5. Orthosis, according to claim 1, characterized in that the abovementioned plantar insole (2) has a slightly supinated arch.

6. Orthosis, according to claim 1 or claim 2, characterized in that it is obtained with a plurality of superimposed layers made of pre-impregnated carbon fiber fabric.

7. Orthosis, according to claim 6, characterized in that said layers of carbon fiber fabric are superimposed with an angle between the fibers of 45°.