WO2003057094A1

WO2003057094A1 - Foot orthosis

Info

Publication number: WO2003057094A1
Application number: PCT/SE2002/002163
Authority: WO
Inventors: Magnus Alm
Original assignee: Magnus Alm
Priority date: 2001-11-27
Filing date: 2002-11-26
Publication date: 2003-07-17
Also published as: SE0103952L; SE520639C2; AU2002367305A1

Abstract

The invention relates to a foot orthosis that comprises a foot-receiving support in the form of a shoe insert (1), as well as a an arm attachable to a lower leg of a user, in relation to which the shoe insert is turnable, more precisely around a point (15) located on a level above the sole part (3) of the shoe insert, the shoe insert being actuated by spring means that always aim to turn the insert back to a predetermined starting position in relation to the arm.

Description

FOOT ORTHOSIS

Background of the Invention

As a consequence of nerve lesions, usually on the calf nerve (nervus peroneus) , people may be affected by a so-called foot-drop, which means that certain muscles in the lower part of the leg and the foot are paralysed to such an extent that the front part of the foot cannot be lifted. Also other neurological damage and diseases, such as myelocele, may be at the bottom of difficulties to control the motions of the foot. With the purpose of facilitating the situation of those affected in respect of the ability to walk, facilities of two principally different types have previously been developed, viz. on one hand so-called dorsal splints, and on the other hand toe- lifting orthoses. A dorsal splint consists of a form-stiff construction that keeps the foot in a given position approximately perpendicularly to the lower part of the leg. In this way, it is certainly avoided that the foot hangs down in an uncontrolled way, but by the foot being immovable, it is nowhere near following the anatomical motion pattern that characterizes natural walk. Therefore, in comparison with dorsal splints, toe-lifting orthoses are advantageous insofar as they allow joint motions between the foot blade and the lower part of the leg at the same time as they help to lift up the foot blade in connection with the foot being about to leave the ground in order to initiate a footstep. However, such foot orthoses neither provide any satisfactory solution to the problem, for instance in respect of the ability to laterally support the foot and the ability to facilitate the adaptations of the foot in. all the different phases that are involved in an anatomically natural step motion, respectively.

Objects and Features of the Invention

The present invention aims at managing the above-men- tioned shortcomings of previously known facilities for people having foot-drop and at providing an improved foot orthosis . Therefore, a primary object of the invention is to provide a foot orthosis that not only facilitates the step motions of the foot by actively actuating the same during different motion phases, but also provides a good lateral support so that the foot is kept straight during the step motions, i.e. without being laterally turned or tilted. Another object is to provide a foot orthosis that in its entirety may be applied to the foot and lower part of the leg of the user without the same being visible from the outside of a shoe or a pair of trousers, respectively, or the like. It is also an object to provide a foot orthosis, which by means of simple changes may be utilized by growing children or people in general, the foot anatomy of which being altered.

According to the invention, at least the primary object is attained by the features defined in claim 1. Preferred embodiments of the foot orthosis according to the invention are furthermore defined in the dependent claims.

Brief Description of the Appended Drawings

In the drawings: Fig 1 is a perspective view of a foot orthosis according to the invention, Fig 2 is an exploded view in perspective of an attachment between an arm and a shoe insert included in the orthosis, Fig 3 is a schematic cut view showing the arm in a basic position in relation to the attachment, Fig 4 is an analogous view showing the arm and the attachment turned in relation to each other, Figs 5-7 are schematic side views showing the foot orthosis in different functional states, Fig 8 is a perspective view showing an alternative embodi- ment of the invention, and

Fig 9 is a side view of the orthosis according to fig 8, shown in a functional state immediately after putting down the heel .

Detailed Description of Preferred Embodiments of the Invention The orthosis shown in fig 1 includes two main components, viz. a support for a foot, in its entirety designated 1, as well as an arm 2, which is turnable in relation to the support 1 and actuated by spring means that always aim to bring back the arm to a certain starting position in relation to the support. In the shown, preferred embodiment, the support 1 consists of a shoe insert, which in addition to a sole part 3 includes a rear, substantially U-shaped border part 4, which is intended to surround and support the heel portion of the foot. The top side of the sole part 1 has a shape being adapted to the shape of the foot of the user, while the bottom side suitably has a shape being adapted to the shape of the shoe in question. In practice, the shoe insert may be made by individ- ual shaping (moulding) of a suitable elastic material having a certain inherent rigidity.

The turnable or tiltable arm 2 is connected to an attachment 5, which in a suitable way is fixed on the outside of the U-formed border part 4 of the shoe insert, and which at the same time forms a joint device for the arm. More precisely, the attachment 5 is fixed to the outside of one of the two long side walls that converge at the rear via a rounded heel cap. The nature of the attachment 5 will be more closely described below, reference being made to figs 2-4. At the upper end thereof, the arm 2 is connected to a cuff, in its entirety designated 6, by means of which the arm may be attached at the lower part of the leg of the user. In the example, the cuff 6 is composed of a soft and comparatively thick cushion 7, e.g. of foam rubber, as well as one or more belts 8, which may be attached in a suitable way, e.g. by means of VELCRO© connections. As is clearly seen in fig 1, the arm 2 consists of a flat, comparatively thin rail, e.g. of plastic or metal.

Reference is now made to figs 2-4, which illustrate how the attachment 5 is composed of two plates 9, 10, the first-mentioned one of which is fixed on the shoe insert 1, while the other one is detachably connected to the first one. The two plates are of a triangular basic shape. The plate 9 has a thickened base part 11 at the bottom thereof, through which a number of attaching elements 12 extend in the form of pins (or screws), which are^' driven in and anchored in the sole part 3 of the shoe insert 1. In the inside of the plate 9, a countersink 13 is formed, the depth of which corresponds to the thickness of the arm 2. Said countersink is delimited by two side flanges 14, the upper ends of which are spaced-apart, so that the countersink 13 opens upwards. In the area between the upper ends of the flanges 14, a circular tumbling 15 is formed, which forms a joint for the arm 2. For this purpose, the arm 2 is made with a hole 16, into which the tumbling 15 is insertable. In the area surrounding the hole 16, the arm 2 is of an enlarged width, whereby two opposite edge surfaces 17 may be pressed against inclined, upper edge surfaces 18 of the flanges 14. A lower end portion 19 of the arm 2 is comparatively narrow and has a gen- tly rounded shape.

In the area below the tumbling or pivot pin 15, two springs 20 are arranged, acting from opposite directions against the lower end portion 19 of the arm. In the shown example, each individual spring consists of an elastically deflect- able wire, having one end anchored in the base part 11 of the plate 9, and the opposite free end pressed against the end portion 19 of the arm. In the attachment, two means 21 are furthermore included for individual adjustment of the spring force in the two spring wires 20. The adjustment means, most clearly seen in fig 2, consists of a cylindrical pulley 21 that is detachably connected to the plate 9 via an eccentric male/ female coupling, the male and female member of which is of a polygonal cross-section shape. Thus, in the example, a hexagonally shaped male member 22 is formed on the pulley 21, which is insertable in a hole or seating 23, .formed hexagonally in an analogous way, in the plate 9. In the mounted state, the pulley 21 is located in association with a lower, arched part of the substantially S-shaped spring wire 20. By applying the male member 22 in different positions in the appurtenant hole 23, the pulley is brought to stretch the free end of the individual spring wire differently hard against the lower end portion 19 of the arm 2.

The second plate 10 serves as a cover plate, which is attachable against the first flanges of the plate 9, e.g. by means of screws.

The plates 9, 10, as well as the arm 2, may in practice be of a very limited thickness (e.g. in the range of 1- 1,5 mm), whereby the total thickness of the attachment becomes limited. In this way, the shoe insert 1 can be inserted in a shoe without obstacles of the outer attachment. In other words, the attachment can be housed between the border part 4 of the insert and the interior of the shoe. In this connection, it should be specifically pointed out that the joint 15 for the arm 2 is situated in the immediate vicinity of the upper portion of the triangular attachment, i.e. at a level above the sole part 3 of the shoe insert 1. This means that the joint is located essentially in front of the ankle around which the foot moves in relation to the lower part of the leg (the fulcra of the foot and the shoe insert thus coincide) . The consequence of this is that the shoe insert 1 can turn in relation to the arm 2 in the same motion pattern as the foot versus the lower part of the leg.

Reference is now made to figs 5-7, illustrating dif- ferent phases during a footstep. The shoe insert 1 is here schematically shown inserted in a shoe, designated 24, through the upwardly turned opening of which the arm 2 protrudes. Depending on the height of the shoe, a larger or smaller part of the lower portion of the arm 2 may be covered by the side piece of the shoe. However, this does not stop turning of the arm, by the same being able to move to and fro in the space inside the shoe side piece.

In a basic position, shown in fig 5 in connection with the putting down phase of the heel of the step motion, the springs 20 keep the shoe insert, and thereby the shoe, at approximately a right angle to the arm 2, which is fixed to the lower part of the leg of the user. More precisely, the sole parts of the insert and the shoe, respectively, extend at approximately 90° to the arm. In this state, the two spring wires 20 are uniformly pressed against the lower end portion 19 of the arm, as is shown in fig 3, and keep said end portion centred between the flanges 14.

After effectuated putting down of the heel, the foot turns clockwise around the ankle, meaning that the insert 1 as well as the shoe 24 are turned clockwise around the joint 15 until the entire sole of the shoe has been pressed against the ground, as is shown in fig 6. During this motion phase, the front spring 20 (to the right in fig 3) is tightened. Hence, when the step motion proceeds to the next phase, viz ■ turning of the lower part of the leg in the clockwise direction around the ankle, the front spring 20 will initially support the turning motion of the lower part of the leg, more precisely up to the perpendicular basic position according to the above, and then the continued turning of the lower part of the leg in the direction clockwise or forwards involves successive tightening of the rear spring 20 (to the left in fig 4) (at the same time as the effect of the front spring is reduced towards zero) . When the step motion approaches the completion thereof and the toe portion of the shoe leaves the ground in the moment immediately after the motion phase that is shown in fig 7, the rear spring 20 will guarantee a turning of the insert, the shoe and the foot therein in the direction clockwise around the joint 15, which means that said spring brings the insert back to the starting position in which the same extends perpendicularly to the arm. In other words, the springs guarantee an alternate effect on the foot of the user in such a way that the foot is constantly brought back to the starting position mentioned above. In this way, the orthosis according to the invention ensures that the step motions of the foot take place in a controlled way, i.e. without the foot hanging enervatedly down from the ankle, the linking connection between the arm and the shoe insert ensuring a good mobility of the foot. Furthermore, the foot is directed laterally on one hand in such a way that the foot blade is kept in the direction straight forward from the lower part of the leg, and on the other hand inasmuch as the foot blade is in itself not tilted laterally.

In figs 8 and 9, an alternative embodiment of the orthosis according to the invention is shown. In this case, two arms 2 are connected to the shoe insert 1, which arms are placed on the outside of the two opposite side pieces of the border part 4. The individual arm 2 is connected to an attachment 5" via an elastically resilient waist portion 15' that serves not only as a joint in the sense that the same enables turning of the arm backwards as well as forwards, but also as a spring means, which through inherent elasticity always aims to bring the arm back to the starting position according to fig 8. In practice, said resilient waist portion 15' may consist of a body of rubber or a rubber-like material that in a suitable way, e.g. through vulcanisation, is connected to the arm and the attachment, respectively. An advantage of this embodiment is that the attachment and the arm may have the same (limited) thickness, e.g. in the range of 1-3 mm. Another advantage is the existence of two arms that operate parallel to each other on both sides of the shoe insert and that direct the shoe insert in a particularly steady way laterally.

Feasible Modifications of the Invention The invention is not limited to solely the embodiments described above and shown in the drawings. Thus, it is for instance feasible to spare the separate attachment on the outside of the shoe insert, more precisely by directly integrating the arm and a resilient joint portion for the same with one or both of the side pieces of the shoe insert. In other words, the arm or the arms may extend in the same vertical plane as the side pieces of the U-formed border part of the shoe insert. Of course, the orthosis may be made with two arms, as in figs 8 and 9, entirely independent of the type of joint that acts between the arm and the shoe insert or attachments on the outside of the same.

Claims

1. Foot orthosis, comprising a foot-receiving support (1) and an arm (2) attachable to a lower leg of a user, in relation to which arm the support is turnable, more precisely around a point (15, 15') located on a level above a lower part (3) of the support, the support being actuated by spring means (20, 15'). that always aim to turn the support back to a predetermined starting position in relation to the arm, c h a r a c- t e r i z e d in that the same comprises a separate attachment (5) applied to the outside of the support, which attachment has two thin plates (9, 10) between which a pivot pin (15) extends, around which the arm (2) is turnable, and that two springs (20) are arranged in a space between the plates (9, 10) and under the pivot pin (15) , which springs act from opposite directions against a lower end portion (19) of the arm.

2. Foot orthosis according to claim 1, c h a r a c t e ri z e d in that the individual spring consists of an elasti- cally deflectable wire (20) , which has one end anchored in the attachment and the opposite free end pressed against the lower end portion (19) of the arm.

3. Foot orthosis according to claim 2, c h a r a c t e r- i z e d in that the attachment includes means (21) for individual adjustment of the spring force in the two spring wires (20).^'

4. Foot orthosis according to claim 3, c h a r a c t e r- i z e d in that the individual adjustment means consists of a pulley (21) that is detachably connected to one of the plates (9, 10) via an eccentric male/female coupling, the male member (22) and female member (23) of which is of a polygonal cross- section shape.

5. Foot orthosis according to any one of the preceding claims, c h a r a c t e r i z e d in that two arms acting parallel to each other are connected to the support.

6. Foot orthosis according to any one of the preceding claims, c h a r a c t e r i z e d in that the support consists of an insert (1) applicable inside a shoe, which insert is of a shape adapted to the foot and in addition to a sole part (3) includes a rear, U-shaped border part (4), on the outside of which the arm or arms (2) are attached.