AU2012244285A1 - Absorbent wrap for a limb - Google Patents

Abstract

An absorbent wrap (10) for a limb or part thereof for use in combination with an immobilising limb orthoses of the type having a compressible liner; the wrap being sized and dimensioned such that it can be folded over and around a limb in a realisably fastenable manner, the wrap comprising a skin contact layer, an absorbent layer that may be the skin contact layer or which may be a further layer. 02/, v W~t

Description

ABSORBENT WRAP FOR A LIMB FIELD OF THE INVENTION 5 The present invention relates to an absorbent wrap for a limb. In particular, the present invention is directed towards an absorbent wrap for use beneath a limb orthoses and especially an ankle-foot orthoses. BACKGROUND OF THE INVENTION 10 The present invention will be described with particular reference to a limb wrap for use with a an immobilising limb orthoses and especially an ankle-foot orthotic device. However, it will be appreciated that the absorbent wrap of the present invention may be used to cover and wrap any limb that is suffering from an injury that may require an absorbent covering around substantially the entire limb. 15 Some examples are weepy leg syndrome in diabetics, excess exudate from traumatic skin injuries, skin grafts and the like. Orthotic devices are used to support, stabilise or position a part of the body. In contrast to conventional plaster casts, limb orthoses can be removed for bathing. 20 An orthotic device can also be removed to allow a medical practitioner accesses the progress of healing and, where the device is used to immobilise a limb after surgery such as arthroplasty, change dressings or otherwise monitor the healing processes as required. 25 Orthotic devices that immobilise limbs typically have a rigid or semi-rigid support and a padded or cushioning liner having an opening into which the limb, or part thereof, may be placed. The liner is then firmly secured around the limb by. means of straps or the like so as to provide a snug and comfortable fit. The liner provides stability, protection and support. Proper fitting of the liner is necessary 1 for proper rehabilitation. When properly fitted, the liner adjusts itself to the contours of the leg to give a snug and comfortable fit. Limb orthoses are generally divided into upper and lower limb devices. Upper 5 limb orthoses include forearm- wrist hand orthoses, hand orthoses and upper extremity orthoses. Lower limb orthoses include ankle-foot orthoses, knee orthoses and knee-ankle-foot orthoses. Orthotic devices that are used by patients who suffer an injury to the lower foot or 10 ankle and allow a patient to walk are commonly known as fracture boots, cam walkers cast boots or medical boots. In the present specification, the term fracture boot will be used. It will be understood that this term refers to any immobilisation device for the foot and ankle. 15 Fracture boots support and immobilise the foot and allows the patient to walk. Fracture boots are widely used to treat ankle sprains, soft tissue injuries, ligament tear, tendonitis and fractures. The basic design of fracture boots is that they have a rigid sole or foot rest, a compressible boot liner that is typically formed from neoprene and hook and loop strapping. In use, a patient puts their foot against 20 the sole. The neoprene liner is then wrapped securely around the leg and fixed in place by the straps. The liner provides stability, protection and compression. Compression is important as it prevents fluids from accumulating and therefore reduces pain and swelling. 25 The advantages of fracture boots over traditional plaster casts are obvious. A patient can walk without crutches, the ability to weight bear facilitates the healing process. One disadvantage is that the foam liner absorbs sweat and accumulates dead skin cells. The moist, warm dark environment within the liner promotes bacterial and fungal growth that occurs generates a foul smell. The moist 30 atmosphere beneath the liner can irritate the skin and in some cases cause an allergic reaction. Even further, the environment against the skin is not sterile and 2 if there are any breaks in the skin, this can lead to infection. It is also extremely important to manage post-surgical wounds to reduce the risk of infection. Health care practitioners therefore recommend that patients wear socks beneath a 5 fracture boot liner and to wash the liner every 4 to 7 days. The liner must be thoroughly dried before refitting the boot. This means that the patient cannot use the boot until it is thoroughly dry. It may also be difficult and painful to fit a sock over a bruised and swollen foot or ankle. Socks also increase the amount of sweat. It may also not be possible to put a sock over a surgical dressing and 10 impossible in cases where a patient has k wires extending from toe joints. Further, any bunching, folding or the like of a sock beneath the liner can inhibit circulation, create pressure injuries or the like. Despite these disadvantages and the wide acceptance of fracture boots as an alternative to plaster cases, there is no alternate solution available to patients. 15 It is therefore an object of the present invention to provide such an alternative. SUMMARY OF THE INVENTION According to a first broad form of the invention there is provided an absorbent 20 wrap for a limb or part thereof for use in combination with an immobilising limb orthoses of the type having a compressible liner; the wrap being sized and dimensioned such that it can be folded over and around a limb in a realisably fastenable manner, the wrap comprising a skin contact layer, an absorbent layer that may be the skin contact layer or which may be a further layer. 25 The absorbent wrap of the present invention is sized and dimensioned so that it can be folded over and around a limb in a releasably fastenable manner. The release means can be any suitable means known in the art and is typically a releasable adhesive tape. This is advantageous as it allows the wrap to be 30 removed for bathing and partially removed to check wounds, healing progress and change wound dressings. 3 The wrap is preferably disposable in that it is not intended to be washed and re used. Generally, the wrap may be disposed of every 1 to 3 days. 5 Preferably, the wrap is provided for use in a sterile manner. Methods for sterilizing wound care products and maintaining them in a sterilized condition prior to use are known in the art. Suitably, the wraps of the present invention are individually packaged and sterilized by gamma irradiation. 10 The size and shape of the wrap will generally depend upon the limb or part thereof. The wrap may have fold lines to assist with folding and wrapping around the limb. In the preferred embodiment where the wrap is for use with a fracture boot, the 15 wrap has a major panel for wrapping about the calf, a minor panel for wrapping around the foot and a connecting portion connecting the two panels. In this way, the two panels can be independently wrapped around the foot and calf for a comfortable fit. 20 The wrap has a moisture absorbent layer that may be a skin contact layer. The moisture absorptivity properties of the layer are suitably selected that they will adsorb the amount of perspiration that a human will perspire from the covered limb over a period of about 12 to about 64 hours, preferably between about 18 to about 56 hours, preferably between about 24 to about 48 hours. For example, the 25 human foot can perspire up to 300ml to 400ml per day. The layer may also be able to absorb excess exudate from a wound. Typically, the absorbent layer is an absorbent nonwoven web. Suitable nonwoven webs are those nonwoven webs which are moisture stable. By "moisture stable", it 30 is meant a nonwoven web which does not lose its integrity when the nonwoven 4 web becomes wetted by a fluid. Exemplary absorbent nonwoven webs include, for example, nonwoven webs of airlaid fiber layers, coform fiber layers, tissue layer meltblown fiber layers or laminates thereof and laminates of airlaid fiber layers, tissue layers, coform fiber layers or meltblown fiber layers or laminates 5 thereof with a nonwoven support. In one embodiment of the present invention, the absorbent nonwoven web is an airlaid web or a coform web, or a laminate of an airlaid web or a coform web with a support nonwoven web. The absorbent layer material is preferably an airlaid material. Airlad materials 10 provide a good degree of absorption for only a relatively thin layer. It is desirable for use with an orthotic device that the layer is thin for patient comfort and that it does not interfere with compression of the joint. Further air laid materials do not appreciably swell upon absorption. This is also important for use beneath a compression liner of a fracture boot. Excessive swelling of the wrap as it absorbs 15 fluid may unduly increase pressure applied to the limb and interrupt circulation. Although this may be addressed by readjusting the straps of the device this is undesirable. "Airlaying" is a known process by which a fibrous nonwoven layer can be formed. 20 In the airlaying process, bundles of small fibers having typical lengths ranging from about 3 to about 52 millimeters are separated and entrained in an air supply and then deposited onto a forming screen, usually with the assistance of a vacuum supply. The randomly deposited fibers then are bonded to one another using, for example, hot air, a spray adhesive, or a binder. The term "airlaid fiber layer" as 25 used herein with reference to the present invention relates to layers obtained by means of an airlaying process. Examples of suitable air-laid materials are those comprising a mixture of at least 70 wt.-% cellulose fibers, from about 2 to 6 wt-% polyethylene powder, 5 to 25 wt 30 % bicomponent or conjugate fibers, and optionally up to 2 wt-% of a latex binder, wherein the sum of the weight percentages of the different components present in the material adds up to 100 wt-%. Alternatively, the absorbent layer material may 5 be a coform material containing between 30 and 50 wt-% polypropylene and between 50 and 70 wt-% cellulose, wherein the sum of the weight percentages of the different components present in the material adds up to 100 wt-%. Specifically, the coform material may contain between 30 and 40 wt-% 5 polypropylene and between 60 and 70 wt-% cellulose. In a further embodiment, the coform material contains 40 wt-% polypropylene and 60 wt-% cellulose. The absorbent material may further comprise additives to improve its properties, such as surfactants or the superabsorbent materials described above to improve the intake or overall absorbent capacity of the absorbent article, respectively. 10 The absorbent layer may be an additional layer to the skin contact layer. In this case, the skin contact layer is suitably a liquid permeable layer that can wick moisture away from the surface of the skin towards the absorbent layer. The skin contact layer may be manufactured from materials known in the art. Known 15 materials include, for example, card weaves and spunbonded nonwovens made of polyester, polypropylenes, polyethylene's, nylon or other heat-bonded fibers. Other polyolefins such as copolymers of polypropylene and polyethylene, linear, low-density polyethylene fiber nonwovens which are finely perforated or mesh-like materials are also suitable. Other suitable materials include composite materials 20 of polymers and nonwoven material. The composite layers are usually formed by extrusion of the polymer on a layer of spunbonded nonwoven to form an integral layer. These materials may contain pigments, such as titanium dioxide to improve the masking properties of the top layer or other additives to improve the properties of the material, like substances improving the hydrophilic properties of the top 25 layer, e.g. surfactants. The absorbent layer may also comprise or further comprise a superabsorbent material. Superabsorbent materials suitable for use in the present invention are known to those skilled in the art, and may be in any operative form, such as 30 particulate form, fibers and mixtures thereof. Generally stated, the superabsorbent material can be a water-swellable, generally water-insoluble, hydrogel-forming polymeric absorbent material, which is capable of absorbing at 6 least about 15, suitably about 30, and possibly about 60 times or more its weight in physiological saline (e.g. saline with 0.9 wt % NaCI). The superabsorbent material may be biodegradable or bipolar. The hydrogel-forming polymeric absorbent material may be formed from organic hydrogel-forming polymeric 5 material, which may include natural material such as agar, pectin, and guar gum; modified natural materials such as carboxymethyl cellulose, carboxyethyl cellulose, and hydroxypropyl cellulose; and synthetic hydrogel-forming polymers. Synthetic hydrogel-forming polymers include, for example, alkali metal salts of polyacrylic acid, polyacrylamides, polyvinyl alcohol, ethylene maleic anhydride 10 copolymers, polyvinyl ethers, polyvinyl morpholinone, polymers and copolymers of vinyl sulfonic acid, polyacrylates, polyacrylamides, polyvinyl pyridine, and the like. Other suitable hydrogel-forming polymers include hydrolyzed acrylonitrile grafted starch, acrylic acid grafted starch, and isobutylene maleic anhydride copolymers and mixtures thereof. The hydrogel-forming polymers may be lightly crosslinked 15 to render the material substantially water insoluble. Crosslinking may, for example, be by irradiation or covalent, ionic, Van der Waals, or hydrogen bonding. The absorbent wrap preferably further comprises a backing layer. The backing layer is suitably formed from a liquid impermeable material. The material may be 20 of any suitable material that is sufficiently liquid-impermeable so that it prevents a significant amount of liquid passing to the foam liner and retain the fluid within the absorption layer. The backing layer may for instance consist of a polymeric film having the desired extensibility. The backing layer may allow atmospheric vapor and moisture to pass through the absorbent article while preventing body fluid 25 from passing through. Suitable polymer materials for use as the backing layer are, for instance, Kraton 1107, a thermoplastic elastomeric A-B-A (styrene isoprene-styrene, S-1-S) copolymer or Solprene 420, which is also a S-1-S copolymer or mixtures thereof. Furthermore, a layer made of different types of polyethylene having different densities may be used. Additionally, 30 microembossed polyethylene or polypropylene films or films of polyolefin foams may be used. The backing layer may also be a layer which may be prepared from a mixture of polyethylene's having different densities. 7 The backing layer may be vapor permeable so as to allow the wrap to breath so as to improve comfort. The backing layer may also provide a surface that in use can resist any rubbing 5 between the wrap and a neoprene liner of a fracture boot. The backing layer may also provide a degree of support to the absorbent layer. The wrap may also include one or more further layers such as additional absorbent layers, bonding layers or the like. 10 Where the wrap includes more than one layer, the layers may be laminated or otherwise joined together by means known in the art. Preferably an adhesive is not used so as to avoid the inclusion unnecessary chemicals. A preferred method of joining year is by ultrasonic welding. 15 It is desirable that the wrap have a degree of stiffness so that it will not be subject to lumping, twisting or otherwise deforming under normal conditions of use, whilst having sufficient flexibility so that it can conform to the shape of the limb. This is advantageous as it provides maximum contact with the skin for comfort and water 20 absorption. Methods of providing materials with a desired flexibility or stiffness are known in the art and depend upon the materials used. In the preferred embodiment where the absorbent layer is made from an air laid nonwoven material, the material may embossed or perforated with holes and/or slits. Perforation points can provide bending points at which the material can be bent 25 without excessively bending the surface to enhance flexibility. The perforations may extend though a backing layer, if present. The thickness of the wrap is typically such that it does not interfere with the function of the orthoses. Typically, the wrap has a width or thickness of between 30 about 0.2mm to about 2.0mm, preferably between about 0.5mm to about 1.5mm, more preferably between about 0.8mm to about 1.2mm. 8 The wrap may also include one or more additives, preferably within the absorbent layer that may absorb odour, mask odour, have antibacterial or antifungal properties, anti-inflammatory properties or wound healing properties. Suitable 5 additives include essential oils such as eucalyptus oil, tea tree oil or lavender oil. According to a further form of the invention, there is provided a method of treating an injury to a limb, comprising providing a wrap as described in the first embodiment, folding the wrap over the injured limb and releasably securing the 10 wrap around the limb. The limb may further be placed within a limb orthoses having a compressible foam liner and fastening the orthoses about the limb and periodically replacing the wrap with a fresh wrap. If the wrap is to be used to treat a non-joint related injury, the 15 wrap may be secured in place using bandages or other means as is known in the art. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a plan view of a preferred absorbent wrap of the present invention for 20 wrapping around a lower limb; Figure 2 is a schematic view of the wrap of figure 1 in the folded position; Figure 3 is a perspective view of a further preferred absorbent wrap of the present invention for wrapping around a lower limb; and Figures 4 to 7 show schematically how the wrap shown in Figure 3 is wrapped 25 around a lower limb. DETAILED DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view of a preferred wrap 10 of the present invention that is for use with a fracture boot. The wrap 10 is made from a layer of an air laid 30 nonwoven material that is ultrasonically bonded to a water impermeable backing 9 layer. The material is formed on a roll as per conventional materials and then stamped to provide the shape of the blank wrap 10. The wrap in the dry state is about 1 mm thick. The wrap is perforated to provide a desired degree of flexibility such that it can conform to the shape of a patient's lower limb.. 5 The air laid nonwoven material provides the skin contact layer. The material is lint free and non-allergenic. The wraps are individually wrapped and sterilized using gamma irradiation. 10 The wrap 10 has two panel portions, a minor panel 12 and a major panel 14 connected together at a fold line 16. The minor panel 10 has opposed side tabs 18 and 20 marked by fold lines 22, 24 that are embossed into the material. The major panel 14 also has opposed side tabs 24, 26, also marked by embossed fold lines 28, 30. 15 The edge 32 of the major panel 14 remote from fold line 16 is inwardly curved towards the centre. In use, the curve sits behind the knee and defines a downward curve that allows for movement of the knee to facilitate patient comfort. 20 The wrap has peelable adhesive strips 34, 36 along the length of one side of each of the major and minor panel tabs. Figure 2 shows the wrap 10 when folded over with the tabs adhered together. It may be seen that the folded wrap is in a boot shape. 25 Figure 3 shows an alternative wrap shape for a lower limb. Figures 4 to 7 shows the steps of folding the wrap around a lower limb. A user's foot is placed on the minor panel 12 with the heel on the fold line 16. The tabs are then folded over the foot and then the calf. 30 10 The encased foot is then placed into a fracture boot and the boot is tightened using the hook and loop fasten straps as per conventional practice. It will be appreciated that the absorbent wrap of the present invention provides a 5 wrap that can be used beneath the foam liner of an orthotic device and in particular a fracture boot to absorb perspiration, collect dead skin cells, absorb exudate from surgical wounds and allow the limb to at least partially breathe. This considerably reduces the bacterial action in the normally closed and humid environment of a neoprene fracture boot liner. This reduces odour, improves 10 patient comfort, reduces the risk of infection and can promote healing of surgical or other wounds. The wrap is relatively thin so that it is comfortable beneath the liner and does not interferes with the compression exerted on the liner to the immobilised joint. Further, it does not unduly swell when moisture is absorbed so as not to add unduly provide excessive compressive forces on the limb that may 15 provide discomfort, or reduce circulation. Still further as the wrap is allergen free and is provided in a sterile form it reduces the risk of irritation, allergic reactions and infection. 20 It will be appreciated that various changes and modifications may be made to the inventions described and claimed herein without departing the spirit and scope thereof. 11

Claims (19)

1. An absorbent wrap for a limb or part thereof for use in combination with an 5 immobilising limb orthoses of the type having a compressible liner; the wrap being sized and dimensioned such that it can be folded over and around a limb in a realisably fastenable manner, the wrap comprising a skin contact layer, an absorbent layer that may be the skin contact layer or which may be a further layer. 10

2. The wrap of claim 1 wherein the limb is a lower limb.

3. The wrap of claim 2, wherein the wrap has a major panel for wrapping about the calf, a minor panel for wrapping around the foot and a connecting portion connecting the two panels.

4. The wrap of any one of claims 1 to 3, wherein the absorbent layer 15 comprises an absorbent nonwoven web.

5. The wrap of claim 4, wherein the nonwoven web is an air laid material.

6. The wrap of claim 5, wherein the air laid material is perforated.

7. The wrap of any one of claims 4 to 6, wherein the absorbent layer further comprises a superabsorbent material. 20

8. The wrap of any one of claims 1 to 7, which further comprises a liquid impermeable backing layer.

9. The wrap of claim 8, wherein the backing layer is vapour permeable.

10. The wrap of claim 8 r claim 9 wherein the backing layer is ultrasonically welded to the absorbent layer. 25

11. The wrap of any one of claims 1 to 9, wherein the absorbent layer further includes an antimicrobial agent.

12. The wrap of any one of claims 1 to 10 having a thickness of between about 0.2mm to about 2.0mm. 12

13. The wrap of claim 12 which the thickness is between about 0.5mm to about 1.5mm.

14. The wrap of claim 12 which the thickness is between about 0.8mm to about 1.2mm. 5

15. The wrap of any one of claims 1 to 14 provided in a sterilized package.

16. An absorbent wrap substantially as hereinbefore described with reference to the Figures.

17. A method of treating an injury to a limb, comprising providing a wrap as described in any one of claims 1 to 16, folding the wrap over the injured 10 limb and releasably securing the wrap around the limb.

18. The method of claim 17, wherein the wrapped limb is placed within a limb orthoses having a compressible foam liner and fastening the orthoses about the limb and periodically replacing the wrap with a fresh wrap.

19. The method of claim 17, wherein the wrap is secured in place using 15 bandages. 13