GB2139089A

GB2139089A - Weight-bearing orthosis

Info

Publication number: GB2139089A
Application number: GB08307715A
Authority: GB
Inventors: John Alan Drew
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-03-21
Filing date: 1983-03-21
Publication date: 1984-11-07
Also published as: GB2139089B; GB8307715D0

Abstract

A shell 1 is shaped so as to support the knee and the proximal part of the leg below the knee. It comprises an anterior portion 2 and a posterior portion 3 of thermosoftening plastics, e.g. polypropylene, which are connected together at an adjustable height relative to each other. The posterior portion 3 is connected to supporting means such as a posterior leaf spring 16. <IMAGE>

Description

SPECIFICATION Weight-bearing orthosis There are many abnormal biomechanical and/or physiological conditions of the lower limb that would benefit from partial "unloading" of the foot. In many situations, the efficacy of any prescribed orthosis may depend on two factors: the fit and the time taken for supply once the need has been identified. The conventional method of making an orthosis has been to take a negative cast from which a positive model of the leg is prepared and to mould a high molecular weight plastics to this cast to create a a bespoke orthosis.

The present invention provides a weight bearing orthosis comprising a shell shaped so as to support the knee and the proximal part of the leg below the knee, and supporting means connected to the shell and extending downwards from the shell, the shell comprising an anterior portion of thermosoftening plastics material, a posterior portion of thermosoftening plastics material, and means for connecting the two portions together at an adjustable height relative to each other, the posterior portion being connected to the supporting means.

The connecting means preferably comprise a clip which is attachable to the anterior portion at a plurality of different heights and which receives a forwardly projecting part of the posterior portion.

Preferably there are two such forwardly projecting parts on opposite sides of the posterior portion, the said parts being releasably interconnectable, e.g. by lacing. The anterior and posterior portions may also be releasably interconnected by strips.

The supporting means is preferably connected to posterior portion at a selected one of a plurality of available heights. For this purpose, groups of connecting holes may be provided in one of these components, one hole in each group being selected to achieve the required height of the posterior portion. The supporting means may, for example, comprise a posterior leaf spring (i.e. a resilient member which descends along the calf, passes round the heel, and projects under the foot) or a pair of metal or plastics side stems for fitting in sockets in a shoe. The posterior leaf spring is preferably of thermosoftening plastics material.

The shell may be provided internally with one or more pressure redistribution or cushioning pads, preferably covered by a lining.

The invention also provides a kit for making an orthosis as described above, the kit comprising a plurality of anterior portions, posterior portions, and supporting means as defined above, and means for connecting any selected anterior portion to any selected posterior portion at an adjustable height relative to each other, any selected posterior portion being connectable to any selected supporting means.

The trained technician will be able to select and assemble components for circumferential pressure redistribution and for vertical and rotational alignment to effect vertical unloading, and with a minimum of reshaping by means of local heating and moulding, as well as grinding, can effect a comfortable bespoke fit.

The invention will be described futhter, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side view of an orthosis; Figure 2 is a rear view of the orthosis; Figure 3 is a rear view of a portion of the orthosis; Figure 4 is an exploded side view of the shell of the orthosis; and Figure 5 is a section through the upper part of the shell.

The orthosis illustrated comprises a shell 1 shaped so as to support the knee and the proximal part of the leg below the knee. The shell 1 comprises an anterior portion 2 and a posterior portion 3 which have been selected from a plurality of such portions of different size and shape, to give the best available fit. The portions 2,3 are premoulded from polypropylene. In order to achieve a bespoke fit, the portions 2,3 are locally remoulded using a hot air gun and, when cool, are tested by offering up to the limb.

On each side of the anterior portion 2, a clip 4 is connected to selected ones of a plurality of holes 6 in the anterior portion 2; forward projections 7 of the posterior portion 3 fit under the respective clips 4.

The height of the clips 4 is adjusted so as to achieve the required relative positions of the patella bar 8 of the anterior portion 2 and the popliteal topline 9 of the posterior portion 3. The projections 7 are connected by lacing 11 over the front of the anterior portion 2. The sides of the portions 2,3 are also connected together by "Velcro" (Trade Mark) straps 12 riveted to the posterior portion 3 above and below the projections 7 and passing through return loops 10 attached to the anterior portion 2.

The posterior shell portion 3 has groups of holes 13 (each group consisting of a vertical row of three holes) corresponding to single holes 14 in a posterior leaf spring 16 which has been selected from a plurality of posterior leaf springs of different size and shape. Connection means such as rivets, screws, or nuts and bolts are passed through the holes 13 and 14 which are in register. Thus, by selecting holes 13 from those available, the height of the posterior portion 3 in relation to the posterior leaf spring 16 can be chosen appropriately. Nuts and bolts are preferably only used during fitting. If temporary fixing allowing subsequent height adjustment to alter the degree of vertical weight relief is required, then screws may be used. If, as will be most common, permanent fixing is required, this will preferably be done by riveting.

The posterior leaf spring 16 is preferably made of "Ortholene" (a Trade Mark for an ultra-high molecular weight polyethylene), which is mouldable at about 190 C. The posterior leaf spring 16 is symmetrical with respect to a vertical plane, so that it is equally usable on either a left or a right leg, and its foot piece 17 is of such length that it will come in front of the metatarsal heads. The posterior leaf spring 16 can be modified in shape (by moulding and/or cutting) to suit particular abnormalities, e.g; for sunken metatarsal head conditions, depressions can be moulded in the foot piece 17 or material can be cut away, in order to relieve pressure points.

When an accurate fitting has been achieved, pressure redistribution and cushioning may be provided by means of preformed pads of different size and density (e.g. of expanded plastics material, preferably thermosoftening). Figure 5 shows pads 18,19,20 corresponding to the patella notch, the condylar prominence, and the popliteal region, respectively. Preferably, the pads 18 to 20 are totally covered by a thin premoulded lining (not shown) of thermosoftening expanded plastics, e.g. "Pelite" (Trade Mark), which lines most of the internal surface of the shell.

The exoskeletal structure described above may be used as a prosthesis for partial foot amputations or as a below-knee temporary prosthesis, for example.

Claims

1. A weight bearing orthosis comprising a shell shaped so as to support the knee and the proximal part of the leg below the knee, and supporting means connected to the shell and extending downwards from the shell, the shell comprising an anterior portion of the thermosoftening plastics material, a posterior portion of thermosoftening plastics material, and means for connecting the two portions together at an adjustable height relative to each other, the posterior portion being connected to the supporting means.

2. An orthosis as claimed in claim 1, in which the connecting means comprises a clip which is attachable to the anterior portion at a plurality of different heights and which receives a forwardly projecting part of the posterior portion.

3. An orthosis as claimed in claim 2, in which there are two said forwardly projecting parts on opposite sides of the posterior portion, the said parts being releasably interconnectable.

4. An orthosis as claimed in any preceding claim, including straps for releasably interconnecting the anterior and posterior portions.

5. An orthosis as claimed in any preceding claim, in which the supporting means is connected to the posterior portion at a selected one of a plurality of available heights.

6. An orthosis as claimed in claim 5, in which groups of connecting holes are provided in the supporting means or the posterior portion.

7. An orthosis as claimed in any preceding claim, in which the supporting means comprises a post erior leaf spring.

8. An orthosis as claimed in claim 7, in which the posterior leaf spring is of thermosoftening plastics material.

9. An orthosis as claimed in any preceding claim, in which the shell is provided internally with at least one pressure redistribution or cushioning pad.

10. An orthosis as claimed in claim 9, in which the pad is covered by a lining.

11. A weight bearing orthosis substantially as described with reference to, and as shown in, the accompanying drawings.

12. A kit for making an orthosis according to any preceding claim, the kit comprising a plurality of anterior portions, posterior portions, and supporting means, as defined in claim 1, and means for connecting any selected anterior portion to any selected posterior portion at an adjustable height relative to each other, any selected posterior portion being connectable to any selected supporting means.