GB2168610A

GB2168610A - Drop-foot appliance

Info

Publication number: GB2168610A
Application number: GB08432193A
Authority: GB
Inventors: Jonathan Mark Vander-Molen
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-12-20
Filing date: 1984-12-20
Publication date: 1986-06-25
Also published as: GB2168610B; GB8432193D0

Abstract

An orthopaedic appliance vacuum moulded in polypropylene for a condition known as drop-foot, has an upper leg piece 1, a lower leg piece 2 and a foot piece 3. The foot piece 3 is angularly and linearly adjustably secured to the lower leg piece 2 by bolts 4 extending through slots 11 using a cremated adjustment disc. Wings 13 on the upper leg piece 1 are connected by a strap 9 extending around the calf of the wearer. Spine portions 14, 19 of the upper and lower leg pieces are formed as nested, part cylindrical channels 15, 20 with co-acting, axially spaced, depressions and protruberances 18 axially adjustably to position the upper leg piece relative to the lower leg piece. A full range of wearers may be fitted using a restricted range of components by virtue of the adjustable connections. <IMAGE>

Description

SPECIFICATION Improvements in orthopaedic appliances This invention relates to orthopaedic appliances and, more particularly, to an orthopaedic appliance of plastics material for a condition known as drop-foot.

There are several designs of such appliances in existence to assist patients to overcome the condition and to walk safely. Some are obtainable as stock items, others as made to measure bespoke appliances.

Established stock designs generally take the form of a one piece moulding, vacuum formed in thermosetting plastics material such as polypropylene. The general shape is that of a letter 'L' and comprises a foot portion which fits under a patient's foot and within the confines of his shoe, and which in combination with the shoe, acts as one unit with the foot.

A vertical member (or members) arises from the heel end of the foot plate and extends upwardly around the back and/or sides of the leg to a position just above the 'belly' of the calf muscle, that is, just above the region of the largest circumference of the calf muscle.

At this position, the vertical member or members are formed into a band around the calf.

In general this band is an incomplete circle fitting against the rear of the leg, just below the knee, and is held in contact with the leg by a variety of fastenings, such as a strap and buckle, or a touch and close VELCRO strap.

The footplate imparts lift to the foot and shoe by the use of counter pressure at the top of the vertical member or members at the calf band where it engages the rear of the patient's calf. In effect, pressure arising from downward rotation of the foot about the ankle joint is resisted by the 'L' shape, the force then being transferred up to the calf band where the leg exerts a force to counteract it.

The design of the appliance and the use of the correct plastics material in terms of weight, thickness, flexibility is of paramount importance to ensure the correct degree of 'lift', a controlled amount of 'spring' for walking on uneven terrain, etc., and a low material fatigue failure rate.

In such established stock designs, taken as ready-made stock items, any adjustment is limited to a selection of the nearest stock size and some local application of remoulding of small areas of pressure by the use of a heat gun and/or by trimming parts away with a knife, Whether these adjustments are made in an orthopaedic clinic or in a workshop by craftsmen there is an element of risk that changes in the durability and possibly the effectiveness of the appliance may occur.

According to the present invention there is provided an orthopaedic appliance formed of plastics material for a condition known as drop-foot including a first portion formed with means adapted to secure an upper part thereof in relation to a patient's leg above a "belly" portion of the patient's calf muscle, a second portion adapted slidably to mate with the first portion, retaining means operative to position the first portion relative to the second portion, a third portion adapted to support the patient's foot and connecting means adapted to position the third portion relative to the second portion whilst permitting angular and linear adjustment between the third portion and the second portion.

Preferably, the second portion is formed with a pair of lobes arranged partially to extend around the patient's ankle and to mate with a corresponding pair of lobes on the third portion with bores in one pair of lobes registering with slots in the other pair of lobes and connecting bolts extending through registering bores and slots in respective lobes.

Suitably, each mating face of the pair of lobes formed with bores is provided with an array of radial crenations, each mating face of the pair of lobes formed with slots is provided with an array of parallel extending crenations and an adjustment disc interposed between co-acting mating faces is formed with corresponding arrays of radial crenations on one face and parallel extending crenations on the opposed face.

Desirably, the first portion and the second portion are formed as channel sections with re-entrant flanges on one portion embracing flanges on the other portion, a multiplicity of depressions on one portion being respectively engageable with a protuberance on the other portion axially to locate the one portion relative to the other portion.

Advantageously, the first portion is formed with a pair of wings arranged partially to extend around the patient's calf each provided with press stud attachment means for an adjustable retaining strap.

The invention will now be described, by way of example, with reference to the accompanying, partly diagrammatic, drawings, in which: Figure 1 is a side elevation of a drop-foot appliance, with a wearer's leg shown in dashed outline; Figure 2 is a front view of the appliance; Figure 3 is a removed section taken on the line Ill-Ill of Figure 1; Figure 4 is an "exploded" perspective view of a lower portion of the appliance; and Figure 5 is an edge view of an adjustment disc.

The appliance includes an upper leg piece 1, a lower leg piece 2 and a foot piece 3, each moulded in a polypropylene plastics material by, for example, a vacuum moulding process.

The lower leg piece 2 is connected to the foot piece 3 by means of a pair of bolts 4 respectively extending through slots 11 in ankle lobes 12 of the foot piece and co-acting with threaded inserts 5 positioned through the lower leg pieces. The upper leg piece 1 is formed, at the upper end thereof, with wings 13 arranged partially to extend around the calf and each having secured thereto a male portion 8 of a press stud. Female portions of the press studs are formed as buckles 6 threaded on to a strap 9 carrying a tibial pad 7.

A spine portion 14 of the upper leg piece 1, having a greater thickness than the wings 13, is moulded as a part cylindrical channel 15 flanked by planar flanges 16. Six closely spaced, hemispherical, depressions 17 are formed centrally of the channel 15 in the concave face thereof with corresponding protuberances 18 being raised on the convex face.

A spine portion 19 of the lower leg piece 2 is moulded as a part cylindrical channel 20 flanked by re-entrant flanges 21 arranged to make a sliding fit with the spine portion 14 of the upper leg piece 1. A single hemi-spherical, projection 22 is formed centrally of the channel 20 in the convex face thereof and is arranged to co-act respectively with each of the depressions 16 axially to position the lower leg piece 2 in relation to the upper leg piece 1.

The lower leg piece 2 is formed, at the lower end thereof, with lobes 23 arranged partially to extend around the ankle each being embossed on the respective outer face with a circular array 24 of crenations of triangular cross-section extending radially from a bore 25 for the threaded insert 5. The respective inner faces of the lobes 12 of the foot pieces 3 are formed with an array 26 of parallel extending crenations of triangular cross-section and, on assembly, adjustment discs 10 are interposed between the respective lobes 23 on the lower leg piece 2 and the lobes 12 on the foot pieces 3. Each adjustment disc 10 is formed on one face 27 with radial crenations corresponding to the array 24 and on the other face 28 with parallel crenations corresponding to the array 26.

To assemble the appliance, the planar flanges 16 of the upper leg piece 1 are registered with the reentrant flanges 21 of the lower leg piece 2 and the two pieces moved axially such that the projection 22 engages with one of the depressions 17 approximately to give the requisite length of the combined pieces. The foot piece 3 is then positioned on the lower leg piece 2 with the slots 11 in register with the bores 25, the adjustment discs 10 being interposed between respective adjacent lobes 12 and lobes 23 and the bolts 4 threaded into the respective threaded inserts 5.

To fit the appliance to a patient, the assembled appliance is offered to the leg and any adjustment in length is effected manually by sliding the upper leg piece 1 relative to the lower leg piece 2 such that the projection 22 engages with an appropriate depression 17.

The foot piece 3 is then adjusted in relation to the lower leg piece 2 by slacking off the bolts 4 and positioning each pair of adjoining lobes 12 and 23 both rotationally and axially of the slots 11 to accommodate any required inversion or eversions of the foot piece, the flexibility of the material permitting differential adjustment as between one pair of adjoining lobes and the other pair. The respective pairs of lobes are retained in the required adjusted position by tightening-up the bolt 4 in the threaded insert 5 to clamp the respective limbs against the adjustment disc 10. Relative rotation is then restrained by engagement of the face 27 of the disc 10 with the radial array 24 of crenations on the lobe 23 and relative axial movement is restrained by engagement of the face 28 of the disc 10 with the parallel array 26 of crenations on the lobe 12. The plastic strap 9, with the tibial pad 7 in position, is then threaded through the buckles 6 to give the requisite length and the buckles attached to the male portions 8 of the press studs to secure the appliance to the leg above the 'belly' of the calf. Since the buckles 6 are provided at each end of the strap 9 and co-operating male portions 8 of the press studs are provided on each wing 13, fastening or opening may be effected on whichever side is convenient to the patient. Furthermore, fastening or opening can be effected through, for example, trousers.

It will be appreciated that aspects of the afore-described appliance may be utilised in other orthopaedic appliances where adjustability in a support against bending is required.

Claims

1. An orthopaedic appliance formed of plastics material for a condition known as dropfoot including a first portion formed with means adapted to secure an upper part thereof in relation to a patient's leg above a "belly" portion of the patient's calf muscle, a second portion adapted slidably to mate with the first portion, retaining means operative to position the first portion relative to the second portion, a third portion adapted to support the patient's foot and connecting means adapted to position the third portion relative to the second portion whilst permitting angular and linear adjustment between the third portion and the second portion.

2. An orthopaedic appliance as claimed in Claim 1, wherein the second portion is formed with a pair of lobes arranged partially to extend around the patient's ankle and to mate with a corresponding pair of lobes on the third portion with bores in one pair of lobes registering with slots in the other pair of lobes and connecting bolts extending through registering bores and slots in respective lobes.

3. An orthopaedic appliance as claimed in Claim 2, wherein each mating face of the pair of lobes formed with bores is provided with an array of radial crenations, each mating face of the pair of lobes formed with slots is provided with an array of parallel extending crenations and an adjustment disc interposed between co-acting mating faces is formed with corresponding arrays of radial crenations on one face and parallel extending crenations on the opposed face.

4. An orthopaedic appliance as claimed in any preceding claim wherein the first portion and the second portion are formed as channel sections with re-entrant flanges on one portion embracing flanges on the other portion, a multiplicity of depressions on one portion being respectively engageable with a protuberance on the other portion axially to locate the one portion relative to the other portion.

5. An orthopaedic appliance as claimed in any preceding claim, wherein the first portion is formed with a pair of wings arranged partially to extend around the patient's calf each provided with press stud attachment means for an adjustable retaining strap.

6. An orthopaedic appliance arranged and constructed substantially as hereinbefore described with reference to the accompanying drawings.