WO2019175589A1

WO2019175589A1 - Medical device

Info

Publication number: WO2019175589A1
Application number: PCT/GB2019/050717
Authority: WO
Inventors: Timothy Cooney
Original assignee: Orthotic Composites Limited
Priority date: 2018-03-14
Filing date: 2019-03-14
Publication date: 2019-09-19
Also published as: GB201804090D0; GB2571965A

Abstract

An orthosis comprises a first composite portion, a second composite portion and a hinge. The first composite portion and second composite portion each comprise a polymer reinforced with a plurality of fibres. The first composite portion is shaped to substantially correspond to a subject's body part on a first side of a joint and comprises a first prominent portion defining an area which is configured, in use, to be spaced apart from the subject's body part. The second composite portion is shaped to substantially correspond to a subject's body part on a second side of the joint and comprises a second prominent portion defining an area which is configured, in use, to be spaced apart from the subject's body part. The hinge comprises a first connecting portion rotatably coupled to a second connecting portion. The first connecting portion is coupled to the first prominent portion and the second connecting portion is coupled to the second prominent portion, thereby rotatably connecting the first and second composite portions. The first connecting portion is not bonded between layers of fibres within the first composite portion and the second connecting portion is not bonded between layers of fibres within the second composite portion.

Description

Medical Device

The present invention relates to medical devices, in particular orthotic devices. More specifically, the present invention relates to an orthotic composite, a method of making the orthotic composite, and an apparatus for carrying out the method.

It has been found that composite fibre materials can be effectively employed to offer an orthotic force pattern, i.e. the application of a force on pressure tolerant areas of a person’s anatomy using an orthosis to force a biomechanical change, whilst

simultaneously being lightweight and strong.

As explained in WO 2017/ 103621 Ai, an orthosis composite may be produced by laying sheets of pre-impregnated carbon fibres on a tool, and then curing the sheets while they remain in place on the tool. The cured product may then be removed from the tool to provide an orthotic composite.

However, in addition to the composite materials, some orthoses also comprise a metal component. For instance, a knee ankle foot orthosis (KAFO) maybe provided to support the lower leg and knee of a patient who suffers from muscle weakness or paralysis. A KAFO may consist of a lower portion and an upper portion connected by a hinge. The lower portion may comprise a footplate, which supports the patient’s foot, a lower elongate strut extending up the patient’s ankle and calf, and a lower cuff by which the KAFO is secured to the patient’s calf. The upper portion may comprise an upper elongate strut extending up and around the patient’s thigh, and an upper cuff by which the KAFO is secured to the patient’s thigh. The hinge is provided adjacent to the patient’s knee, allowing the patient to bend their leg while wearing the KAFO.

Metal components, such as a hinge, are normally integrated into the composite material. Accordingly, the orthosis can be produced by providing a hinge comprising a first flange and a second flange, whereby the first flange is rotatably connected to the second flange. The first flange can be sandwiched between two or more layers of the sheets of pre-impregnated carbon fibres on the tool defining the lower portion of the KAFO and the second flange can be sandwiched between two or more layers of the sheets of pre-impregnated carbon fibres on the tool defining the upper portion of the KAFO. The sheets can then be cured to provide the KAFO. However, any metal component which is used will be required to withstand the heat and pressure of the curing cycle. Furthermore, it is essential that the metal component does not move during the curing process, as this could affect the alignment of the orthotic composite. Similarly, the unavoidable expansion of the metal during the curing cycle can also weaken the bond between the metal and the composite structure. Accordingly, the bond between the metal component and the composite structure tends to form a weak point in the final product which can fail over time. Furthermore, the metal stem can also fail due to stresses at the exit point of the laminate. The present invention arises from the inventors work in attempting to overcome the problems associated with the prior art.

Hence, in accordance with a first aspect of the invention, there is provided an orthosis comprising:

a first composite portion comprising a polymer reinforced with a plurality of fibres, and being shaped to substantially correspond to a subject’s body part on a first side of a joint;

a second composite portion comprising a polymer reinforced with a plurality of fibres, and being shaped to substantially correspond to a subject’s body part on a second side of the joint; and

a hinge comprising a first connecting portion rotatably coupled to a second connecting portion, wherein the first connecting portion is coupled to the first composite portion and the second connecting portion is coupled to the second composite portion, thereby rotatably connecting the first and second composite portions, characterised in that the first connecting portion is not bonded between layers of fibres within the first composite portion and the second connecting portion is not bonded between layers of fibres within the second composite portion.

Advantageously, the hinge can be added after the first and second composite portions have been cured, and so does not need to withstand the heat and pressure of the curing cycle. Furthermore, the hinge can be more strongly coupled to the first and second composite portions than would have been possible in prior art devices.

Preferably, the first composite portion comprises a first prominent portion defining an area which is configured, in use, to be spaced apart from the subject’s body part, and the first connecting portion is coupled to the first prominent portion. Preferably, the first prominent portion is configured, in use, to be provided substantially adjacent to the joint. Preferably, the first prominent portion defines a substantially planar surface.

Preferably, the second composite portion comprises a second prominent portion defining an area which is configured, in use, to be spaced apart from the subject’s body part, and the second connecting portion is coupled to the second prominent portion. Preferably, the second prominent portion is configured, in use, to be provided substantially adjacent to the joint. Preferably, the second prominent portion defines a substantially planar surface.

Preferably, the first connecting portion is shaped to have the same profile as the first prominent portion and the second connecting portion is shaped to have the same profile as the second prominent portion. Accordingly, in embodiments where the prominent portions are substantially planar, the first and second connecting portions are preferably also substantially planar.

Preferably, the first connecting portion is fixedly coupled to the first composite portion, and more preferably the first prominent portion, by a resin. Preferably, the second connecting portion is fixedly coupled to the second composite portion, and more preferably the second prominent portion, by a resin. Preferably the resin is an epoxy resin.

Alternatively, or additionally, the first connecting portion maybe fixedly coupled to the first composite portion, and more preferably the first prominent portion, by a mechanical fastening. Furthermore, the second connecting portion may be fixedly coupled to the second composite portion, and more preferably the second prominent portion, by a mechanical fastening.

Accordingly, the first connecting portion may comprise a first plate disposed on a first side of the first composite portion, preferably on a first side of the first prominent portion, and the second connecting portion may comprise a second plate disposed on a first side of the second composite portion, preferably on a first side of the second prominent portion, and the hinge may further comprise:

a first projection coupled to the first plate and extending through an aperture in the first composite portion; a second projection coupled to the second plate and extending through an aperture in the second composite portion; and

a joining portion extending between and coupled to the first and second projections, wherein the joining portion is disposed on a second side of the first and second composite portions.

Preferably, the first projection is fixedly coupled to the first plate. Accordingly, the first connecting portion may be viewed as comprising the first plate and the first projection. Preferably, the second projection is fixedly coupled to the second plate. Accordingly, the second connecting portion may be viewed as comprising the second plate and the second projection. Preferably, the joining portion is rotatably coupled to the first projection. Preferably, the joining portion is rotatably coupled to the second projection.

Preferably, the first side of the first and second composite portions is an internal side of the first and second composite portions. Preferably, the second side of the first and second composite portions is an external side of the first side of the first and second composite portions. It may be appreciated that, in use, the internal side of the first and second composite portions is the side closest to the patient’s body part and the external side of the first and second composite portions is the side furthest from the patient’s body part.

An orthosis may be considered to be a brace, splint, or other artificial external device serving to support the limbs or spine or to prevent or assist relative movement. The orthosis may comprise an upper-limb orthosis, a lower-limb orthosis or a spinal orthosis.

The upper limb orthosis may be selected from the group consisting of a clavicular and shoulder orthosis, an arm orthosis, an elbow orthosis, a forearm-wrist orthosis, a forearm-wrist-thumb orthosis, a forearm-wrist-hand orthosis, a hand orthosis, and an upper-extremity orthosis. Accordingly, the joint maybe a wrist joint or and elbow joint.

The lower limb orthosis may be selected from the group consisting of an ankle-foot orthosis (AFO), a knee-ankle-foot orthosis (KAFO), a knee orthosis and a hip-knee- ankle-foot orthosis (HKAFO). Accordingly, the joint maybe an ankle joint, a knee joint or a hip joint.

In a preferred embodiment, the orthosis comprises an ankle-foot orthosis (AFO), a knee orthosis, a knee-ankle-foot orthosis (KAFO), or a hip-knee-ankle-foot orthosis (HKAFO).

In an embodiment where the orthosis comprises an AFO, the first composite portion may correspond to a patient’s foot and the second composite portion may correspond to a patient’s lower leg.

In an embodiment where the orthosis comprises a knee orthosis, the first composite portion may correspond to a patient’s lower leg and the second composite portion may correspond to a patient’s upper leg.

In an embodiment where the orthosis comprises a KAFO, the first composite portion may correspond to a patient’s foot and lower leg and the second composite portion may correspond to a patient’s upper leg. Alternatively, the KAFO orthosis may comprise a first composite portion correspond to a patient’s foot, a second composite portion corresponding to a patient’s lower leg, a third composite portion corresponding to a patient’s upper leg, a first hinge rotatably connecting the first composite portion to the second composite portion and a second hinge rotatably connecting the second composite portion to the third composite portion. The orthosis may comprise a prosthetic component. The prosthetic component may be an artificial limb.

Accordingly, in one embodiment, the orthosis is configured for use by a lower leg amputee. A lower limb amputee may be understood to have had their leg amputated below the knee. Accordingly, the first composite portion may comprise a lower leg prosthetic component coupled to an orthotic component configured to correspond to the remainder of a patient’s lower leg and the second composite portion may correspond to a patient’s upper leg. In an alternative embodiment, the orthosis is configured for use by a lower arm amputee. A lower arm amputee may be understood to have had their arm amputated below the elbow. Accordingly, the first composite portion may comprise a lower arm prosthetic component coupled to an orthotic component configured to correspond to the remainder of a patient’s lower arm and the second composite portion may correspond to a patient’s upper arm.

The orthosis may comprise a hinge, wherein in use the hinge is disposed to a side of the joint. Preferably, the hinge is disposed on an external side of the joint.

It maybe appreciated that if the orthosis is an AFO, a knee orthosis, a KAFO or a HKAFO it may be for use on a first leg and/ or foot of a patient. The patient may also have a second leg. Accordingly, the external side of the joint maybe understood to refer to a portion of an external side of the first leg, wherein the portion is substantially adjacent to the joint. Similarly, the external side of the first leg may be understood to be the side of the first leg which is generally disposed furthest from the second leg.

Alternatively, it may be appreciated that if the orthosis is an elbow orthosis it may be for use on a first arm of a patient. The patient may also have a body. Accordingly, the external side of the joint maybe understood to refer to a portion of an external side of the first arm, wherein the portion is substantially adjacent to the joint. Similarly, the external side of the first arm may be understood to be the side of the first arm which is generally disposed furthest from the body.

In a more preferred embodiment, the orthosis may comprise a pair of hinges, wherein in use the pair of hinges are disposed either side of the joint. Accordingly, in use, a first hinge may be disposed on an external side of the j oint, and a second hinge may be disposed on an external side of the joint.

In accordance with a second aspect, there is provided a method of making an orthosis, the method comprising: - - providing a tool substantially corresponding to a subject’s body part comprising a joint;

positioning a curable material comprising a plurality of fibres over a portion of the tool;

curing the curable material to cause it to become a rigid structure;

- removing the rigid structure from the tool; separating the rigid structure substantially adj acent to the j oint to obtain separate first and second composite portions, wherein the first composite portion is shaped to substantially correspond to the subject’s body part on a first side of the joint and the second composite portion is shaped to substantially correspond to the subject’s body part on a second side of the joint;

providing a hinge comprising a first connecting portion rotatably coupled to a second connecting portion; and

fixing the first connecting portion to the first composite portion and fixing the second connecting portion to the second composite portion to provide an orthosis.

In accordance with a third aspect, there is provided a method of making an orthosis, the method comprising: - providing a tool substantially corresponding to a subject’s body part comprising a joint or providing a pair of tools, where a first tool corresponds to a subject’s body part on a first side of a joint and a second tool corresponds to a subject’s body part on a second side of the joint;

positioning a curable material comprising a plurality of fibres over a portion of the or each tool to define first and second structures;

- curing the curable material to cause it to become rigid first and second

composite structures, wherein the first composite portion is shaped to substantially correspond to the subject’s body part on a first side of the joint and the second composite portion is shaped to substantially correspond to the subject’s body part on a second side of the joint;

- removing the first and second composite structures from the or each tool;

Advantageously, the methods of the second and third aspects allow a hinge to be fixed to the tool after the curable material has been cured. Accordingly, the hinge does not need to withstand the heat and pressure of the curing cycle. Furthermore, since the hinge can be added be a technician after the cure cycle, it is substantially easier to obtain the desired alignment and/or to modify the position of the component. The inventors have found that it is possible to produce orthoses much faster using the method of the first aspect than using prior art methods.

Preferably, the methods of the second and third aspects produce the orthosis of the first aspect.

The tool may correspond to at least a portion of a foot, a leg, a hand and/or an arm. For instance, if the method is a method of making a KAFO, the tool may correspond to the subject’s upper leg, knee, lower leg and foot, and the joint is the knee. Alternatively, if the method is a method of making an AFO, the tool may correspond to the subject’s lower leg, ankle and foot, and the joint is the ankle.

Preferably, the or each tool comprises a prominent portion, wherein the prominent portion is disposed substantially adjacent to the joint and defines an area spaced apart from the surface of the corresponding body part. Preferably, the prominent portion defines a surface which is prominent of the surface of the corresponding body part. Accordingly, the portion of the or each tool over which the plurality of fibres is placed preferably comprises at least a portion of the prominent portion. Accordingly, in the second aspect, positioning a curable material comprising a plurality of fibres over a portion of the or each tool may comprise positioning a curable material comprising a plurality of fibres over a portion of the tool comprising at least a portion of a prominent portion. Accordingly, the resultant rigid structure preferably comprises a prominent portion. Preferably, separating the rigid structure comprises separating the rigid structure at the prominent portion. Preferably, separating the rigid structure comprises cutting the rigid structure.

Accordingly, in the third aspect, positioning a curable material comprising a plurality of fibres over a portion of the or each tool may comprise:

- positioning a curable material comprising a plurality of fibres over a first

portion of the tool disposed on a first side of the joint, or over a portion of the first tool, wherein the first portion of the tool or the portion of the first tool comprises at least a portion of a prominent portion; and

positioning a curable material comprising a plurality of fibres over a second portion of the tool disposed on a second side of the joint, or over a portion of the second tool, wherein the second portion of the tool or the portion of the second tool comprises at least a portion of a prominent portion.

Accordingly, preferably both the first and second composite structures comprise a prominent portion configured, in use, to be spaced apart from the subject’s body part.

Preferably, the prominent portion defines a substantially planar surface.

Advantageously, both the first and second composite structures comprise a

substantially planar portion, enabling the hinge to be joined thereto more easily.

The curable material maybe either a UV-curable or a heat-curable material.

Preferably, the curable material is in sheet form. In some embodiments, the curable material may be tensioned after they have been applied to the polymeric material. In other embodiments, tensioning is not required.

Preferably, the curable material comprises at least one composite sheet including an inner core of the plurality of fibres impregnated with a polymer resin. The or each composite sheet maybe of the type often referred to as a“pre-preg”, in that it comprises a fibre composite sheet p re-impregnated with resin.

The resin may comprise a thermosetting resin or a thermoplastic resin. Preferably, the resin comprises a thermosetting resin. Preferably, the thermosetting resin is an epoxy resin. The curable material is preferably uncured at the time of being placed over the tool. Advantageously, this allows the curable material to be carefully worked around the 3D shape of the tool. Preferably, the plurality of fibres are manipulated, such that they form a three dimensional shape represented by the tool. Due to the tacky uncured resin, the pre-preg holds its position well on the tool surface.

The plurality of fibres may comprise carbon fibres, polymer fibres and/or glass fibres. The polymer fibres may comprise polyamide fibres and/or polyethylene fibres. The polyamide fibres may comprise aramid fibres, such as those sold under the brand name Kevlar®. The polyethylene fibres may comprise high molecular weight polyethylene fibres, such as those sold under the brand name Dyneema®. The plurality of fibres may comprise unwoven fibres. The unwoven fibres may comprise unidirectional fibres. Additionally, or alternatively, the plurality of fibres may comprise woven fibres. The woven fibres may comprise twill fibres. The method preferably comprises disposing a layer of polymeric material over the tool prior to positioning the curable material over the tool. Subsequent to positioning the curable material over the tool, and prior to curing the curable material, the method may comprise wrapping a releasable membrane over the tool and the first and second curable materials. The membrane may be a polytetrafluoroethylene-based film. A vacuum-permeable breather fabric may be placed over the releasable membrane. This resultant structure may then be placed in a heat-tolerant vacuum bag comprising a vacuum valve.

The vacuum bag-enclosed tool maybe placed in an oven (e.g. convection oven) or an autoclave. The oven or autoclave may have a vacuum tube entering into it through an aperture in one side thereof. The tool is preferably placed under vacuum pressure whilst in the oven or autoclave.

Advantageously, the vacuum pressurizes the curable material thereby sucking out any air trapped within the substrate consisting of the tool and curable materials. Any resultant air bubbles would act to weaken the structure.

The temperature in the oven or autoclave maybe gradually increased until it reaches a curing temperature. The temperature maybe increased over at least io minutes, more preferably, at least 20 minute or 30 minutes, and most preferably at least 40 minutes.

The tool may then be heated for at least 1 hour or 2 hours at the curing temperature.

Preferably, the tool is heated for between 1 hour and 5 hours at a curing temperature. More preferably, the tool is heated for between 2 hours and 4 hours at a curing temperature. Most preferably, the tool is heated for about 3 hours at a curing temperature.

The curing temperature is preferably between 60 °C and 180 °C, more preferably between 70 °C and 170 °C, between 80 °C and 160 °C or between 90 °C and 150 °C, and most preferably between 100 °C and 140 °C, or between 110 °C and 130 °C. Fixing the first connecting portion to the first composite portion and fixing the second connecting portion to the second composite portion may comprise disposing a second curable material between the first connecting portion and the first composite portion and between the second connecting portion and the second composite structure.

In one embodiment, the second curable material comprises a glue. Preferably, the glue used is a thermosetting glue. More preferably, the glue is an epoxy glue. The glue may be degassed before it is applied.

In an alternative embodiment, the second curable material comprises a layer of curable material. The layer of curable material may comprise a layer of resin. The resin may comprise a thermosetting resin or a thermoplastic resin. Preferably, the resin comprises a thermosetting resin. Preferably, the thermosetting resin is an epoxy resin. In one embodiment, the layer of curable material does not comprise any fibres.

Alternatively, the layer of curable material may comprise fibres, preferably glass fibres, more preferably woven glass fibres. Advantageously, the glass fibres improve the handleability of the layer of curable material. Preferably, the first connecting portion of the hinge is shaped to have the same profile as the first prominent portion and the second connecting portion of the hinge is shaped to have the same profile as the second prominent section. Accordingly, in

embodiments where the prominent portions are substantially planar, the first and second connecting portions are preferably also substantially planar.

Preferably, the method comprises fixing the first connecting portion to the first prominent portion and fixing the second connecting portion to the second prominent portion. Accordingly, the method may comprise:

disposing a second curable material on the first connecting portion and/or the first composite portion;

positioning the first connecting portion substantially adjacent to the first composite portion such that the second curable material is disposed between the first connecting portion and the first composite portion; and retaining the first connecting portion in place relative to the first composite portion and curing the second curable material, thereby fixing the first connecting portion to the first composite structure. Preferably, the second curable material is disposed on the first connecting portion and/or on the first prominent portion and the first connecting portion is then positioned substantially adjacent to the first prominent portion.

A vacuum maybe applied to the first connecting portion and first composite portion while the second curable material is curing.

In embodiments where the second curable material is a glue, curing the second curable material may comprise maintaining the first connecting portion, the first composite portion and the second curable material at room temperature and allowing the second curable material to cure.

In embodiments where the second curable material is a layer of curable material, curing the second curable material may comprise applying heat to the first connecting portion, the first composite portion and the second curable material to cause the second curable material to cure.

The method may comprise:

disposing a second curable material on the second connecting portion and/or on the second composite portion;

- positioning the second connecting portion substantially adjacent to the second composite portion such that the second curable material is disposed between the first connecting portion and the first composite portion; and

retaining the second connecting portion in place relative to the second composite portion and curing the second curable material, thereby fixed the second connecting portion to the second composite structure.

Preferably, the second curable material is disposed on the second connecting portion and/or on the second prominent portion and the second connecting portion is then positioned substantially adjacent to the second prominent portion and held in place until the glue has set. A vacuum maybe applied to the second connecting portion and second composite portion while the second curable material is curing.

In embodiments where the second curable material is a glue, curing the second curable material may comprise maintaining the second connecting portion, the second composite portion and the second curable material at room temperature and allowing the second curable material to cure.

In embodiments where the second curable material is a layer of curable material, curing the second curable material may comprise applying heat to the second connecting portion, the second composite portion and the second curable material to cause the second curable material to cure.

The first connecting portion may comprise a first plate with a first projection extending therefrom, the second connecting portion may comprise a second plate with a second projection extending therefrom, and the hinge may further comprise a joining portion configured to extend between and reversibly couple to the first and second projections. Preferably, the joining portion is configured to rotatably coupled to the first projection. Preferably, the joining portion is configured to rotatably coupled to the second projection.

Preferably, the method comprises forming a first hole in the first composite portion. Preferably, the hole is formed in the prominent portion of the first composite portion. Preferably, the method comprises forming a second hole in the second composite portion. Preferably, the hole is formed in the prominent portion of the second composite portion.

Preferably, the method comprises:

placing the first connecting portion so that the first plate is disposed on a first side of the first composite portion and the first projection extends through the first hole;

placing the second connecting portion so that the second plate is disposed on a first side of the second composite portion and the second projection extends through the second hole; and

- coupling the joining portion to the first and second projections on a second side of the first and second composite portions. In a most preferred embodiment, the method comprises:

disposing a glue on a face of the first plate;

placing the first connecting portion so that the face of the first plate is disposed adjacent to a first side of the first composite portion and the first projection extends through the first hole;

disposing a glue on a face of the second plate;

placing the second connecting portion so that the face of the second plate is disposed adjacent to a first side of the second composite portion and the second projection extends through the second hole;

allowing the glue to set, optionally under a vacuum, thereby bonding the first connecting portion to the first composite portion and bonding the second connecting portion to the second composite portion; and

coupling the joining portion to the first and second projections on a second side of the first and second composite portions, thereby rotatably coupling the first and second composite structures to provide an orthosis.

Preferably, the first side of the first and second composite structures is an internal side of the first side of the first and second composite structures. Preferably, the second side of the first and second composite structures is an external side of the first side of the first and second composite structures. It may be appreciated that, in use, the internal side is the side closest to the patient’s body part and the external side is the side furthest from the patient’s body part. The method of the second aspect may also comprise covering any fibres which were exposed when the rigid structure was cut with a layer of resin. Preferably, the layer of resin is epoxy resin.

In accordance with a fourth aspect there is provided a tool for manufacturing an orthosis, the tool substantially corresponding to a subject’s body part comprising either a joint or a region adjacent to a joint, the tool comprising a prominent portion disposed at or substantially adjacent to the joint and defining a surface spaced apart from the surface of the corresponding body part. Advantageously, the tool can be used in the methods of the second and third aspects. Preferably, the tool comprises plaster of Paris or resin. The resin may be epoxy or polyurethane resin. Preferably, the tool comprises a layer of polymeric material disposed over the plaster of Paris or epoxy resin. The polymeric material may comprise nylon, polyethylene, polytetrafluoroethylene or polypropylene.

Preferably, the prominent portion defines a substantially planar surface. Preferably, the prominent portion defines a surface which is prominent of the surface of the corresponding body part. All of the features described herein (including any accompanying claims, abstract and drawings), and/ or all of the steps of any method or process so disclosed, may be combined with any of the above aspects in any combination, except combinations where at least some of such features and/ or steps are mutually exclusive. For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying Figures, in which: -

Figure 1 is a plaster cast of a patient’s leg forming a tool that is used for preparing an orthotic device;

Figure 2 is the plaster cast of a patient’s leg of Figure 1 with a polymeric sheet fitted thereto;

Figure 3 is the plaster cast of a patient’s leg with a polymeric sheet fitted thereto of Figure 2 with pre-impregnated fibre sheets laid thereon;

Figure 4 is a top plan view of a hinge;

Figure 5 is a perspective view of the hinge of Figure 4;

Figure 6 is a side an orthotic composite; and

Figure 7 is a perspective view of the orthotic composite of Figure 6.

Examples

Plaster of Paris is safe, adaptable and cheap. Accordingly, Plaster of Paris is used in orthotic manufacturing to both capture the shape of a person’s anatomy and modify a workable and unique‘tool’ 2 for manufacturing. An example of a tool 2 used to make an orthosis 4 is shown in Figure 1. A unique tool 2 may be made for each individual who requires an orthosis 4. Alternatively, it is possible to use a standard tool 2 to create multiple identical orthoses 4, which reduces costs but means that it may be necessary for the size and fitting of the orthoses 4 to be adjusted after manufacture to ensure they are suitable for the user. A standard tool is usually made using a pourable two part epoxy or polyurethane‘tooling’ resin, or milled from a pre-fabricated block of‘epoxy tooling board’. These materials are more durable than plaster allowing use for multiple cures, for instance the inventors aim for over 1000 cures per tool.

The tool 2 shown in Figure 1 comprises a plaster portion 6 corresponding in shape to a portion of the client’s anatomy, for example an arm, leg or foot. In the embodiment illustrated in Figure 1, the tool comprises portions corresponding to a person’s foot 8, lower leg 10 and upper leg 12. A metal rod 14 extends out from the plaster portion 6, by which the tool 2 can be held steady by locating the metal rod 14 in a clamp 16. The rod 14 is hollow and also provides the source of vacuum pressure, as described below.

The tool 2 shown in Figure 1 comprises two prominent portions. A left hand side prominent portion 18 is disposed on the left hand side of the tool and extends between the lower leg portion 10 and the upper leg portion 12. A corresponding right hand side prominent portion (not shown) is disposed on the other side of the tool 2. Each of the prominent portions 18 define a flat surface 22 which is prominent of the surrounding surface of the tool 2.

A 1 to 2 mm thick layer of homopolymer polypropylene sheet 24 is heated in an infrared oven at 190 °C for 30 minutes. When warm, the polypropylene sheet 24 is then draped over the plaster portion 8 of the tool 2 and a seal 26 is created by joining the

polypropylene 20 with itself, as shown in Figure 2. A seal 28 is also created around the rod 14, i.e.“vacuum tube”.

As mentioned above, the hollow rod 14 is inserted into the plaster portion 6. This allows ease of handling, and also allows the rod 14 to be connected to a vacuum system (not shown). For example, the rod 14 can be connected to a rotary vane vacuum pump or a domestic vacuum cleaner. One hole in the rod 14 is usually sufhcient to create sufficient vacuum pressure to seal the polypropylene around the tool 2. However, on larger tools 2, it may be preferred to drill into the internal rod 14 in suitable sections in order to spread the vacuum pressure sufficiently. The vacuum is maintained until the polypropylene 24 has cooled to ambient temperature or about 21 °C. The length of time for allowing cooling depends upon the ambient room temperature. For example, if this is maintained at about 21 °C, it can take about 45 minutes to cool sufficiently.

After the polypropylene 24 has cooled, the vacuum is removed and the polypropylene sheet 24 retains the shape of the tool 2. The polypropylene-covered tool 2 can then be moved freely around the workshop using rod 6, as it is no longer tied to the vacuum system.

As shown in Figure 3, layers of p re-impregnated (pre-preg) fibres 30 are then placed on the polypropylene-covered tool 2 in the desired locations for making the orthosis 4.

The pre-preg fibres 30 may comprise carbon, aramid, high molecular weight polyethylene fibres and/or glass fibres. Each of these fibres maybe impregnated with a similar resin system, such as an epoxy based system. The fibres are usually woven like a fabric, and so manipulation of the pre-preg fibres 30 weave over and around polymeric material on the tool may be required. Thus, the pre-preg fibres 30 are manipulated such that they form a three dimensional shape represented by the tool. Due to the tacky uncured resin, the pre-preg holds the position well on the tool surface. The desired thickness is obtained by adding multiple layers of pre-preg to a pre- determined‘fibre lay-up design’. One preferred curable material that maybe used is a carbon fibre epoxy resin system pre-preg, which may be obtained from Gurit, Cytex or PRF Composites in which the resin is curable at about 120 °C.

In the illustrated embodiment, the layers of pre-preg fibres 30 are cut and positioned on the tool to define:

- a footplate 32 disposed on the base of the foot portion 8;

a calf cuff 34 disposed on the lower leg portion 10;

a thigh cuff 40 disposed on the upper leg portion 12;

a first strut 36 which extends between the footplate 32 and the calf cuff 34; and - left and right hand second struts second struts 38 which are disposed on the left and right hand side of the tool 2, respectively, and each extend between the calf cuff 34 and the thigh cuff 40 and respectively cover the left and right prominent portions 18 to define a planar section 39 (only the left second strut 38 is shown in the Figure ). The pre-preg fibres 30 are then cured. The step of curing the fibres can involve either UV-curing or heat-curing the curable material. The pre-preg is wrapped in a releasable membrane, such as a polytetrafluoroethylene-based film. A vacuum-permeable breather fabric is then placed over the releasable membrane, and this resultant structure is then placed in a heat-tolerant vacuum bag comprising a vacuum valve. The vacuum bag-enclosed tool is then placed in a convection oven (or an autoclave). The oven or autoclave has a vacuum tube entering into it through an aperture in one side thereof. The tool 2 is placed under vacuum pressure whilst in the oven or autoclave.

The vacuum pressurizes the pre-preg thereby sucking out any air trapped within the substrate. Any resultant air bubbles would only act to weaken the structure. The tool 2 may then be heated for at least 1 or 2 hours at 120 °C.

The curing process does not damage the protective polypropylene layer 20 which is placed over the tool 2. Accordingly, the tool 2 can be used in multiple cure cycles without any adjustment to the tool 2 or the protective polypropylene layer 20 being necessary.

The resultant structure is then‘demoulded’ from the tool 2 by mechanically prying it off the tool 2. The polypropylene sheet 20 does not stick to the resin, and so this process is straightforward unless there is some sort of geometry that‘locks’ the device in place.

The structure will then be cut roughly midway through the planar section 39 on each side to provide lower and upper portions 31, 33. The lower and upper portions 31, 33 may also require their edges to be smoothed.

A hinge 44, as shown in Figures 4 and 5, may be used to connect the lower and upper portions 31, 33. The hinge 44 comprises a planar lower back plate 46 and a planar upper back plate 48. First and second lower projections 50, 52 extend from an upper surface 53 of the lower back plate 46. Each of the lower projections 50, 52 comprises a base 58, which is disposed adjacent to the lower back plate 46, and collar (not shown) which extends above the base portion 58. Both the base 58 and collar have a circular cross section, with the collar defining a smaller outer radius than the base portion 58. For each projection 50, 52, the collar is disposed concentrically about the same axis as the base 58. The internal surface of the collar defines a screw thread.

Similarly, first and second upper projections 54, 56 extend from an upper surface 55 of the upper back plate 48. The first and second upper projections 54, 56 are as described above, in relation to the first and second lower projections 50, 52 above. A first connecting portion 60 defines a substantially straight profile and comprises two apertures sized to fit over the collars, but not the bases 58, of the lower and upper first projections 50, 54. A second connecting portion 62 defines a substantially curved profile and comprises two apertures sized to fit over the collars, but not the bases 58, of the lower and upper second projections 52, 56.

Accordingly, when the technician wishes to attach the hinge 44 to the lower and upper portions 31, 33 they would first drill holes in the planar section 39, 43. The holes in the lower portion’s planar section 39 would be configured to receive the respective bases 58 of the first and second lower projections 50, 52. Similarly, the holes in the upper portion’s planar section 43 would be configured to receive the respective bases 58 of the first and second upper projections 54, 56.

The technician would then apply a strong epoxy glue to the upper surface 53 of the lower back plate 46 and would then insert the first and second lower projections 50, 52 through the holes in lower portion’s planar section 39 so that the upper surface 53 of the lower back plate 46 was positioned flush with an internal surface of lower portion’s planar section 39. The lower back plate 46 would be held in place until the glue had set. To avoid voids forming in the glue, a vacuum may be applied. This could be achieved by degassing the glue before application to the upper surface 53 of the lower back plate 46. Alternatively, or additionally, it could be achieved by placing the structure, comprising the lower portion 31 and lower back plate 46, in a vacuum bag and applying a vacuum while the glue is curing. The curing could occur via a chemical catalyst, which may occur at room temperature. Alternatively, heat may be applied to the structure to cause the glue to cure.

Alternatively, instead of applying a glue to the lower back plate, the technician may position a sheet or pre-cured resin over an internal surface of lower portion’s planar section 39. The technician would then insert the first and second lower projections 50, 52 through the holes in the lower portion’s planar section 39 so that the upper surface

53 of the lower back plate 46 was positioned substantially flush with the resin sheet disposed therebetween. The lower back plate 46 would be held in place until the resin had cured. The technician would then place the structure, comprising the lower portion 31 and lower back plate 46, in a vacuum bag, apply a vacuum and place the bag comprising the structure in the oven. The structure could then be heated to cure the resin. The technician would use an analogous method to attach the upper back plate 48 to an internal surface of the upper portion’s planar section 39. The technician would then place the first connecting portion 60 over the collars of the lower and upper first projections 50, 54, and would insert screws 64 into the collars to hold the first connecting portion 60 in place. Similarly, the technician would then place the second connecting portion 62 over the collars of the lower and upper second projections 52, 56, and would insert screws 64 into the collars to hold the second connecting portion 62 in place.

It will be appreciated that the technician would apply a hinge to connect the planar portions 39, 43 on both the left and right hand sides of the lower and upper portions 31, 33

The collars are able to rotate within the first and second connecting portions 60, 62, allowing the hinge to rotate. Furthermore, the shape and size of the first and second connecting portions 60, 62 causes the hinge to rotate in a substantially Fibonacci shaped curve, similar to the natural rotation of the knee.

The technician would also cover any fibres which were exposed due to the cutting of the composite with a layer of resin. This improves the strength of the finished orthosis 4. This could be achieved by applying layers of epoxy over any cut edges and curing the lower and upper portions 31, 33, optionally at the same time as curing the lower and upper portions 31, 33 to attach the hinge 44. Alternatively, resin may be painted over the cut edges and left to cure. This could be done before or after the hinge 44 is attached to the lower and upper portions 31, 33.

Straps 66 and padding etc., as necessary, can also be added as indicated by the design.

A completed orthosis 4 is shown in Figures 5 and 6.

Summary

The ability to add a metal component after the orthotic composite has been cured means that components which would not have withstood the cure cycle can still be used. Furthermore, since the component can be added by a technician after the cure cycle, it is substantially easier to obtain the desired alignment. Alternatively, if the metal component is placed incorrectly, it is still possible to modify the device. Conversely, using prior art methods, it would have been necessary to completely refabricate the product.

The inventors have found that it is possible to produce orthoses much faster using the methods described herein than using prior art methods.

Finally, the join between the metal component and the composite structure is stronger, reducing the likelihood of failure over time.

Claims

Claims l. An orthosis comprising:

a first composite portion comprising a polymer reinforced with a plurality of fibres, and being shaped to substantially correspond to a subject’s body part on a first side of a joint and comprising a first prominent portion defining an area which is configured, in use, to be spaced apart from the subject’s body part;

a second composite portion comprising a polymer reinforced with a plurality of fibres, and being shaped to substantially correspond to a subject’s body part on a second side of the joint and comprising a second prominent portion defining an area which is configured, in use, to be spaced apart from the subject’s body part; and

a hinge comprising a first connecting portion rotatably coupled to a second connecting portion, wherein the first connecting portion is coupled to the first prominent portion and the second connecting portion is coupled to the second prominent portion, thereby rotatably connecting the first and second composite portions, characterised in that the first connecting portion is not bonded between layers of fibres within the first composite portion and the second connecting portion is not bonded between layers of fibres within the second composite portion.

2. An orthosis according to claim l, wherein the first prominent portion is configured, in use, to be provided substantially adjacent to the joint and the second prominent portion is configured, in use, to be provided substantially adjacent to the joint.

3. An orthosis according to either claim 1 or claim 2, wherein the first prominent portion and the second prominent portion each define a substantially planar surface.

4. An orthosis according to any preceding claim, wherein the first connecting portion is shaped to have the same profile as the first prominent portion and the second connecting portion is shaped to have the same profile as the second prominent portion.

5. An orthosis according to any preceding claim, wherein the first connecting portion is fixedly coupled to the first composite portion by a resin, and the second connecting portion is fixedly coupled to the second composite portion by a resin.

6. An orthosis according to claim 5, wherein the resin is an epoxy resin.

7. An orthosis according to any preceding claim, wherein the first connecting portion is fixedly coupled to the first composite portion by a mechanical fastening, and the second connecting portion is fixedly coupled to the second composite portion by a mechanical fastening.

8. An orthosis according to any preceding claim, wherein the orthosis comprises a clavicular and shoulder orthosis, an arm orthosis, an elbow orthosis, a forearm-wrist orthosis, a forearm-wrist-thumb orthosis, a forearm-wrist-hand orthosis, a hand orthosis, an upper-extremity orthosis, an ankle-foot orthosis (AFO), a knee-ankle-foot orthosis (KAFO), a knee orthosis or a hip-knee-ankle-foot orthosis (HKAFO).

9. An orthosis according to any preceding claim, wherein in use the hinge is disposed to a side of the joint.

10. An orthosis according to any preceding claim, wherein in use the hinge is disposed on an external side of the joint.

11. An orthosis according to any preceding claim, wherein the orthosis comprises a pair of hinges, wherein in use the pair of hinges are disposed either side of the j oint.

12. A method of making an orthosis, the method comprising:- providing a tool substantially corresponding to a subject’s body part comprising a joint, wherein the tool comprises a prominent portion, wherein the prominent portion is disposed substantially adjacent to the joint and defines a surface which is prominent of the surface of the corresponding body part;

positioning a curable material comprising a plurality of fibres over a portion of the tool comprising at least a portion of the prominent portion;

curing the curable material to cause it to become a rigid structure;

- removing the rigid structure from the tool;

separating the rigid structure substantially adj acent to the j oint to obtain separate first and second composite portions, wherein the first composite portion is shaped to substantially correspond to the subject’s body part on a first side of the joint and comprises a first prominent portion defining an area which is configured, in use, to be spaced apart from the subject’s body part and the second composite portion is shaped to substantially correspond to the subject’s body part on a second side of the joint and comprises a second prominent portion defining an area which is configured, in use, to be spaced apart from the subject’s body part;

fixing the first connecting portion to the first prominent portion and fixing the second connecting portion to the second prominent portion to provide an orthosis.

13. A method of making an orthosis, the method comprising:- providing a tool substantially corresponding to a subject’s body part comprising a joint or providing a pair of tools, where a first tool substantially corresponds to a subject’s body part on a first side of a joint and a second tool substantially corresponds to a subject’s body part on a second side of the joint, wherein the or each tool comprises a prominent portion, wherein the prominent portion is disposed substantially adjacent to the joint and defines a surface which is prominent of the surface of the corresponding body part;

positioning a curable material comprising a plurality of fibres over a first portion of the tool, wherein the first portion of the tool is disposed on a first side of the joint, or positioning a curable material comprising a plurality of fibres over a portion of the first tool, wherein the first portion of the tool or the portion of the first tool comprises at least a portion of the prominent portion;

positioning a curable material comprising a plurality of fibres over a second portion of the tool, wherein the second portion of the tool is disposed on a second side of the joint, or positioning a curable material comprising a plurality of fibres over a portion of the second tool, wherein the second portion of the tool or the portion of the second tool comprises at least a portion of the prominent portion;

curing the curable material to cause it to become rigid first and second composite structures, wherein the first composite portion is shaped to substantially correspond to the subject’s body part on a first side of the joint and comprises a first prominent portion defining an area which is configured, in use, to be spaced apart from the subject’s body part and the second composite portion is shaped to substantially correspond to the subject’s body part on a second side of the joint and comprises a second prominent portion defining an area which is configured, in use, to be spaced apart from the subject’s body part; removing the first and second composite structures from the or each tool; providing a hinge comprising a first connecting portion rotatably coupled to a second connecting portion; and

14. A method according to either claim 12 or claim 13, wherein the method comprises:

- disposing a second curable material on the first connecting portion and/or the first composite portion;

positioning the first connecting portion substantially adjacent to the first composite portion such that the second curable material is disposed between the first connecting portion and the first composite portion;

- retaining the first connecting portion in place relative to the first composite portion and curing the second curable material, thereby fixed the first connecting portion to the first composite structure;

disposing a second curable material on the second connecting portion and/or the second composite portion;

- positioning the second connecting portion substantially adjacent to the second composite portion such that the second curable material is disposed between the second connecting portion and the second composite portion; and

retaining the second connecting portion in place relative to the second composite portion and curing second curable material, thereby fixed the second connecting portion to the second composite structure.

15. A method according to claim 14, wherein a vacuum is applied to the first connecting portion and first composite portion and to the second connecting portion and second composite portion while the curable material is curing.

16. A method according to either claim 14 or claim 15, wherein the curable material is a glue, preferably a thermosetting glue.

17. A method according to either claim 14 or claim 15, wherein the curable material comprises a layer of curable material comprising a layer of resin, preferably a thermosetting resin.

18. A tool for manufacturing an orthosis, the tool substantially corresponding to a subject’s body part comprising either a joint or a region adjacent to a joint, the tool comprising a prominent portion disposed at or substantially adjacent to the joint and defining a surface spaced apart from the surface of the corresponding body part.