WO2009064189A1

WO2009064189A1 - Clubfoot splint

Info

Publication number: WO2009064189A1
Application number: PCT/NL2008/050730
Authority: WO
Inventors: Mark Stefan Besselink; Nicolaas Gerardus Adrianus Van Leerdam; Leendert Van Bekkum
Original assignee: Kunst & Van Leerdam Ip B.V.
Priority date: 2007-11-16
Filing date: 2008-11-17
Publication date: 2009-05-22
Also published as: NL2002219C2; NL1034707C2; NL2002219A1

Abstract

A splint for connecting a clubfoot for treating on the one leg of a patient, in particular a baby, to the lower zone of the other leg of the patient comprises: a shoe fitting around the foot; an element which can be coupled to the lower zone of the other leg; and a connecting rod which is present between the shoe and the element and which is connected to the shoe and the element via two respective pivot means, each with three rotation degrees of freedom; wherein the degree of freedom of rotation around the central axis of the connecting rod defines a rotation angle range of at least 30°, and each of the two other degrees of freedom of rotation define a rotation angle range of at least 135°.

Description

CLUBFOOT SPLZMT

The invention relates to a splint with which a clubfoot in babies is corrected. A clubfoot is a congenital abnormality in the position of the foot, wherein the foot is tilted downward and inward and wherein the forefoot points inward. About two hundred children are born with clubfeet in the Netherlands every year.

A common treatment method for correcting a clubfoot is to fix the foot and the ankle in the correct position using a plaster cast, after which an operation usually follows in which the Achilles tendon is lengthened, after which a splint is prescribed for the child until he/she is four years old. The child wears this splint day and night until it begins to stand and walk. In this latter case the splint is only worn at night. The splints known in practice comprise two orthopaedic shoes which are rigidly connected to each other at a determined fixed angle using a connecting rod. This angle is the angle of correction of the splint. A known splint with the above described properties is the "Dennis Brown splint".

A significant drawback of the splints known in practice is that the angle of correction is a fixed angle, whereby the ankle joint can no longer move. This has an adverse effect on the development of the ankle.

Known from US-A-5 401 235 is a splint in which the angle of correction is not fixed. According to this publication each foot can rotate around one fixed axis,^' perpendicularly of the connecting rod, wherein a spring produces the necessary corrective force. A significant drawback of said splints known in practice and the splint according to US-A-5 401 235 is that both feet are connected to each other such that a free movement of both legs relative to each other is not possible. whereby the kicking reflex of the baby is suppressed and whereby crawling is made difficult, this adversely affecting the development of the child. A drawback of the splint according to US-A-5 401 235 is that this splint has a free angle of correction in only one direction.

The invention is based on the insight that correction is desired in three directions, so that the baby can kick, and later crawl, without substantial limitations.

In respect of the above the invention provides a splint for connecting a clubfoot for treating on the one leg of a patient, in particular a baby, to the lower zone of the other leg of the patient, which splint comprises: a shoe fitting around the foot; an element which can be coupled to the lower zone of the other leg; and a connecting rod which is present between the shoe and the element and which is connected to the shoe and the element via two respective pivot means, each with three rotation degrees of freedom; wherein the degree of freedom of rotation around the central axis of the connecting rod defines a rotation angle range of at least 30°, and each of the two other degrees of freedom of rotation define a rotation angle range of at least 135°.

Attention is drawn to US-A-3 777 747. Known from this publication is a clubfoot splint which has two degrees of freedom of rotation.

A similar technique is known from FR-A-2 740 970. US-A-5 382 225 shows and describes a clubfoot splint in which the soles of two shoes are coupled to a rigid connecting rod by means of ball joints. After positioning the shoes in the correct manner the ball joint is fixed. A correction as desired according to the invention is thus not possible herewith. In addition, the pivot angles are limited to low values in two of the three degrees of freedom.

Attention is also drawn to DE-U-20 2006 005 117. Also known from this publication is a clubfoot splint which has certain degrees of freedom, but these differ greatly from those desired according to the invention.

According to a specific aspect of the invention, the splint can have the special feature that the connecting rod is elastic, forms part of the pivot means, and determines one of the three degrees of freedom.

Such a connecting rod can for instance consist of a rubber or a rubber-like material.

Alternatively, an elastic connecting rod can be embodied such that the connecting rod is a torsion rod. A torsion rod can for instance take a more or less strip-like form and have a more or less flat form when at rest. The ends can rotate relative to each other, whereby an elastic torsional deformation occurs in the rod. In its intermediate position the rod has a natural rest position, without stop means being necessary for this purpose.

According to yet another aspect of the invention, the splint can be provided with spring means and stop means, which together define a rotation rest position in at least one of the degrees of freedom.

It is important to emphasise that use is made according to the invention of wholly free-running hinges, so not hinges for once-only setting and fixing, with a range of a minimum of about 135°-180°, in both the endo/exo-rotation and the varus/valgus-tilting. This has the purpose of ensuring that the child can crawl and walk in a fairly natural way with the splint. In addition, the recommended position for a clubfoot treatment, i.e. a slight valgus tilt and about 70° exorotation, must be imposed by means of spring means. It is also noted in this respect that the connecting rod embodied as torsion rod is an option, but is not essential for the treatment of a clubfoot.

In a practical embodiment the splint is embodied such that the spring means comprise at least one torsion spring.

In the case where the patient has two clubfeet, the splint can be embodied such that the element is a second shoe.

In the case of one clubfoot the splint can have the special feature that the element comprises an ankle strap.

The invention will now be elucidated with reference to the accompanying drawings.

In the drawings: figure 1 shows a perspective view of a clubfoot splint according to the invention with two shoes; figure 2 shows a perspective view of a hinge with two degrees of freedom, as applied in the splint according to figure 1; figure 3 shows a view corresponding with figure 2 of a ball joint to which a resetting spring is added; figure 4 shows a perspective view corresponding with figure 1 of a second embodiment in which the splint comprises one shoe and one adjustable ankle strap; figure 5 is a rear view of the splint according to figure 1 which shows that the left-hand hinge has a free pivotability of about 180°; and figure 6 is a top view of the splint according to figure 1 which shows that the hinges also have a free pivotability of 135°-180° in the plane perpendicularly of figure 5.

Figure 1 shows a clubfoot splint 31 according to the invention in a first embodiment. The splint comprises two shoes 1, preferably of the orthopaedic type, and a connecting rod 2. Connecting rod 2 is connected to shoes 1 by means of hinges 3.

Hinges 3 are of the type with two degrees of freedom. Rod 2 is embodied as torsion rod which is accommodated in a sleeve. This torsion rod 2 defines the third degree of freedom of rotation in combination with spring means .

The rod could also be of a rigid type. In that case it must be connected to hinge 3 by means of a pivoting element such that the overall hinge construction has three degrees of freedom of rotation.

Figure 2 shows the way in which hinges 3 are constructed and connected to shoes 1. A plate 5 has through-holes 21, 22 for passage of bolts, screws or other suitable elements for coupling to sole 23 of shoe 1. In the drawn embodiment the sole 23 has for this purpose through-holes 24. Broken lines 25, 26 indicate the eventual coupling between plate 5 and sole 23 by means of connecting elements (not drawn) via through- holes 21, 22, 24.

Rod 2 is connected to a hinge core 27, round which a hinge bush 6 is rotatable around a central pivot shaft 9. A torsion spring 10 exerts such a pivoting force that the front side of shoe 1 is forced outward.

Hinge bush 6 carries a pivot shaft 7 around which two tongues 28, bent into round shape, of plate 6 extend in freely rotatable manner. A torsion spring 4 exerts a spring force such that the outer side of shoe 1 undergoes a slight upward spring force.

Figure 3 shows an alternative wherein shoe 1 and connecting rod 2 are connected to each other by means of a schematically shown ball joint 11, to which a resetting spring 12 is added. This resetting spring 12 in the form of a draw spring fulfills the same function as torsion spring 4 according to figure 2.

Figure 4 shows a splint 32 which differs from the splint 31 according to figure 1 in the sense that splint 32 comprises one shoe 1 and one ankle strap 13 arranged on the other end of connecting rod 1. Ankle strap 13 is of known adjustable type and is connected to connecting rod 2 by means of a ball joint 33. Figure 5 shows in full lines a rear view of splint 31 in the situation where the shoes point forward, so perpendicularly of the plane of the drawing, counter to the action of springs 4 and 10. Broken lines in the same figure show that connecting rod 2 can pivot downward through about 90°, for instance while maintaining the spatial position of shoe 1. The drawing also shows that rod 2 can move upward, likewise at an angle of about 90°. It will be apparent herefrom that the overall rotation freedom of hinges 4 is about 180°.

It is apparent from the top view of figure 6 that hinge 4 also allows a rotation freedom of a maximum of about 180° in the plane of the drawing.

Not drawn is that, owing to the presence of torsion spring 2, a mutual rotation of shoes 1 corresponding to the elastic torsion of this rod is also possible.

The stop means optionally used to determine the rest position in a degree of freedom can be of any known and generally usual type. A great advantage of the splint according to the invention relative to any prior art reference known to the inventors is that, when the splint is used, the legs of the patient can move with a great measure of freedom relative to each other, whereby the kicking reflex and crawling remain possible for the baby. The development of the child is hereby impeded considerably less than when use is made of any prior art technique. In addition, the ankle associated with the foot for treating can move better due to the movable angle of correction, whereby the development of the ankle is impeded considerably less than in the prior art.

Claims

1. Splint for connecting a ciuoroot ior treeiuing on the one leg of a patient, in particular a baby, to the lower zone of the other leg of the patient, which splint comprises: a shoe fitting around the foot; an element which can be coupled to the lower zone of the other leg; and a connecting rod which is present between the shoe and the element and which is connected to the shoe and the element via two respective pivot means, each with three rotation degrees of freedom; wherein the degree of freedom of rotation around the central axis of the connecting rod defines a rotation angle range of at least 30°, and each of the two other degrees of freedom of rotation define a rotation angle range of at least 135°.

2. Splint as claimed in claim 1, wherein the connecting rod is elastic, forms part of the pivot means, and determines one of the three degrees of freedom.

3. Splint as claimed in claim 2, wherein the connecting rod consists of a rubber or a rubber-like material.

4. Splint as claimed in claim 2, wherein the connecting rod is a torsion rod.

5. Splint as claimed in any of the claims 1-4, comprising spring means and stop means, which together define a rotation rest position in at least one of the degrees of freedom.

6. Splint as claimed in claim.5, wherein the spring means comprise at least one torsion spring.

7. Splint as claimed in any of the claims 1-6, wherein the element is a second shoe.

8. Splint as claimed in any of the claims 1-6, wherein the element comprises an ankle strap.