Title of Invention

A NOVEL DIABETIC FOOTWEAR FOR PREVENTION OF FOOT SOLE ULCERS

Abstract

This invention relates to a novel diabetic footwear for prevention of foot sole ulcers. The new footwear, namely, sandals and shoes used for prevention and healing of foot sole ulcers are designed based on important engineering principle of unloading the foot sole. The design geometry of the insole and outer sole of the new footwear, namely, sandals and shoes, used for prevention of foot sole ulcers, the selection of materials for the insole and outer sole, their hardness, and the density are determined by three dimensional finite element stress analysis of foot- footwear composite model, which give the least foot sole stresses, thus preventing foot sole ulcers. The design geometry of the insole and outer sole, heel insert or flat bottomed rocker with extended shoulders and their axis of fixation on the outer sole of the new footwear, ( sandals and shoes) used for healing of foot sole ulcers , hardness, density and the selection of type of materials to be used for the above components of the new footwear, are determined by three dimensional finite element stress analysis of foot-footwear composite model, which give the least foot sole stresses, thus helping in very fast healing of even long duration non-healing foot sole ulcers in any part of foot sole of diabetic patients.

Full Text

A Novel Diabetic Footwear for Prevention of Foot Sole Ulcers Field of Invention This invention in general relates to the Biomedical Engineering field. In particular this invention relates to an unique category of footwear intended to be used by diabetic subjects for prevention of foot sole ulcers. Prior Art Diabetes mellitus is increasing globally. Foot ulceration is a common sequel to diabetes mellitus. Foot ulceration in the diabetic patient is the most common single precursor to amputation having been identified in 85% of lower extremity amputations. Foot sole ulcers occur in feet that are either insensate or ischemic or both or subject to high foot pressures. Therefore, it becomes important to prevent high pressures in the early stage itself by providing appropriate footwear to the diabetic subjects to reduce the foot pressure thus prevent ulcers and be suitable to be worn by them depending upon their work requirement and weather conditions . There are some diabetic subjects (with complete loss of foot sole sensation) having already foot sole ulcers in different parts of the foot sole which do not heal for a long time due to high foot pressures. These diabetic subjects have to be given appropriate foot wear to reduce the foot sole pressures to heal the ulcers quickly and be suitable to be worn by them depending upon their work requirement and weather conditions. The footwear for prevention of foot sole ulcers, of diabetic subjects offered in the western world, is mainly shoes. " A comprehensive concept of the medical, functional, and technical requirements of the type of footwear is still lacking to date " (Dahmen et al 2001, Diabetic Care, Vol. 24, 705-709). " Footwear that, is aesthetically acceptable to people with diabetes and prior foot ulcers has received little study in the United States" (Reiber et al 2002, J. Rehab. Research & Development, Vol. 39, 615-622). The footwear available commercially in the western world for diabetic subjects for prevention of foot sole ulcers is shown in Figure 1 (Reiber et al 2002, J. Rehab. Research & Development, Vol. 39, 615-622). This is a shoe with hard outer sole (1), and a thin medium hard insole and leather upper (2) with lace to properly hold the foot in the shoe. The footwear for prevention of foot sole ulcers, available in the market for diabetic subjects in India, are shown in Figure 3 and Figure 4. Figure 3 shows a simple sandal with thin hard rubber insole (1 ) and hard rubber outer sole (2 ), front leather strap (3) to hold big toe and wide leather back strap (4) connected to the front strap. This type of footwear is not suitable for diabetic subjects since the thin hard insole does not reduce foot pressure and does not prevent foot ulcers. The leather straps are also hard without any inner soft lining. Therefore, this will introduce high friction between the upper part of foot and sandal, possibly giving rise to ulcers in the upper part of the foot. This footwear without a back strap going around the ankle, will not be able to hold the foot inside the footwear for diabetic subjects with complete loss of foot sole sensation. The inability of the diabetic subjects with sensory loss to hold the foot inside the footwear often results in the foot getting injured by hitting the external objects. Figure 4 shows a sandal available in the Indian market as 'Dia-sole for foot rehef for diabetic subjects' possibly for prevention of foot sole ulcers. This sandal has thin insole (1 ) made of microcellular plastic (MCP) in the fore-foot part and very thin insole in the heel part of footwear, supported by very hard moulded plastic outer sole (2) with back (3) and front leather straps (4); both the straps are fitted with Velcro to hold the foot inside the sandal. This footwear without the help of buckle on the Velcro strap cannot be made to adjust the foot size within the footwear with appropriate grip and therefore gives rise rubbing action between the foot and the strap which could result in ulcers in the upper part of the foot. These type of footwear is also not able to accommodate swelling in the diabetic foot. Since the insole is not appropriately designed for its thickness, hardness and the material density, it is not efficient to reduce the foot pressure to the required extent and thus will not be able to protect the foot from foot sole ulcers. The durability of the footwear is low due to the material of the insole being not suitable for wash and wear and it is also very costly. There are no footwear (sandals or shoes) available in the Indian market for healing of foot sole ulcers. The Limitations of Prior Art Limitations of Existing Footwear for Prevention and Healing of Foot Sole Ulcers: 1. Foot wear both in India or in the westem world is not designed by stress analysis of foot-footwear composite model for minimizing the foot sole stresses which are necessary to unload the foot sole and reduce the foot sole pressure. Therefore, the thickness, hardness, type of material and its density used for the footwear insole and outer sole are not appropriate to reduce the diabetic foot sole pressures to the required extent and thus, to protect the diabetic foot from foot sole ulcers or healing of ulcers. 2. The footwear insole is very thin less than appropriate for reduction of foot sole stresses. 3. The existing footwear available in the Indian market (sandal type) for relief of pressure with thin micro-cellular plastic insole (MCP) absorbs water, not suitable for wash and wear, has low diorability. 4. The footwear insole is not of appropriate thickness and harder than required hardness and therefore not able to reduce foot sole pressure to the required level and thus inefficient in prevention of foot sole ulcers and it is also heavy. 5. The footwear outer sole is thicker and made of material harder than required hardness and therefore is not able to reduce foot sole stresses below necessary level to protect the foot sole from ulcers. 6. The footwear is heavier than required and therefore uncomfortable. 7. There is no soft inner lining attached to the straps of the sandal or to the irmer part of shoe upper and thus it gives rise to high frictional forces between the footwear upper and the foot upper part which results in ulcers in diabetic subjects with complete loss of foot sole sensation. 8. In diabetic patients with complete loss of foot sole sensation, it is essential to constrain the foot within the footwear to avoid injury to foot by hitting against outside objects. Both the sandals available in the Indian market are not able to take care of this aspect. 9. The existing footwear is very costly cannot be afforded by most of the diabetic patients. 10. There is no footwear available in the Indian market for healing of foot sole ulcers. 11. One model of the shoe available in the western world is meant for healing of foot sole ulcers in the fore foot areas only and that design is not efficient since it is not designed by the stress analysis of the foot-shoe composite model. Therefore, it is not able to unload and reduce the foot sole stresses around the ulcer region to the required extent and thus it takes considerable time (4 to 6 months) for healing of ulcers. 12. There are no footwear (sandals or shoes) available in India or in the westem world for healing of foot sole ulcers in the heel as well as the in the mid-foot region of the diabetic foot. Because of the limitations listed above, it has become very essential and urgent to develop appropriate footwear (sandals to be used in southern India for tropical weather and shoes for use in cold weather or as per the need of the profession) for use by the diabetic patients for prevention of foot sole ulcers and healing of foot sole ulcers (if they already exist) in all parts of the foot sole area. This invention "A Novel Diabetic Footwear for Prevention of Foot Sole Ulcers" has many improvements as compared to earlier used footwear. 1. The new footwear (different designs of sandals and shoes) for diabetic subjects are unique, have new features and many improvements are made as compared to the existing devices. They are designed based on engineering principles of unloading the foot sole to reduce the foot sole stresses or pressures to prevent the foot sole ulcers or healing them (if they already exist) quickly. This is done by stress analysis of three dimensional foot-footwear composite model by using finite element method so as to select dimensions of footwear such as thickness, hardness and materials of footwear insole, outer sole and rocker bottom and its location (wherever it is used) to minimize the foot sole stresses appropriately for prevention and healing of foot sole ulcers, in all regions of the foot sole, within a short time (within 3 to 4 weeks time). 2. The new footwear is able to constrain the diabetic foot within the footwear by appropriate adjustable straps to prevent external injuries. 3. It is able to take care of any swelling in the diabetic foot and also have an appropriate grip on the foot by adjustable straps provided with buckle and Velcro straps. 4. The straps in the footwear or shoe uppers are provided with soft inner linings to avoid or minimize friction between foot and footwear, thus prevent foot ulcers. 5. The new footwear for healing of diabetic foot sole ulcers is provided with novel aesthetic design of rocker with its axis appropriately located in different parts of the outer sole to reduce the foot sole stresses in the ulcer and other regions to speed up the process of healing. 6. The new footwear is light, comfortable and will be made available at low cost (3 to 10 times less than the commercially available footwear depending upon the type of footwear used by the diabetic patients). 7. The new footwear will be made available in all foot sizes, for ladies and men and in 3 colours, depending on the choice of the diabetic subject. 8. The insoles and outer soles of the new footwear are of appropriate thickness, hardness and weight to minimize foot sole stress or pressure (about 3 times less than the commercially available footwear), 9. The new footwear is comfortable, can heal foot sole ulcers in all regions of the foot sole in 3 - 4 weeks time which is 5 - 6 times faster than the healing time needed for footwear available in the westem world. 10. The new footwear (sandal as well as shoe type) has insole made of micro-cellular rubber (MCR) of appropriate quality, hardness, thickness, and washable insole which does not absorb water, and has high durability. It is to be noted that the prior art description gives in detail information of the technology, method, process and system known in the prior art. It explains the deficiency in the related art and the object of the invention being to overcome or surmount the problem associated with the prior art. This forms the essential feature and object of the invention. SUMMARY OF INVENTION The inventors have made great effort to provide new footwear which meet the requirements of the diabetic patients and also the industry and to overcome the problems associated in the prior art. To achieve the above object according to first aspect and feature of the present invention there is provided with different types of footwear for prevention of foot sole ulcers to improve, efficiency. According to second aspect and feature of the invention in addition to first feature the invention comprises footwear which is unique, light weight, comfortable, and economical than existing footwear. At the outset of the description which follows, it is to be understood that ensuing description only illustrate particular forms of this invention. However, such particular forms are only an exemplary embodiment without intending to imply any limitation on the scope of this invention. Accordingly, the description is to be understood as an exemplary embodiment and reading of the invention is not intended to be taken restrictively. The above and other objects features will be clear from the following description of preferred embodiment taken in conjunction with accompanying drawings. The foregoing description is outlined rather broadly preferred and alternative feature of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features of the invention will be described hereinafter that form the subject of claims of the invention. Those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiment as a basis of for manufacturing by way of and modifying other structures for carrying out the same purposes of the present invention. Those skilled in the art should realize such equivalent conception do not depart from the spirit and scope of the invention in its broadest form. The present invention pertains to new footwear for use by diabetic subjects, consists of unique footwear, for prevention of foot sole ulcers. Again, there are two types of footwear, namely sandals and shoes. The sandals are meant to be used in tropical weather and to suit habits of the diabetic population. The shoes are to be used in mostly colder weather and to suit the habits and professional requirements of the diabetic subjects. The new footwear, namely, sandals and shoes used for prevention and healing of foot sole ulcers are structured based on engineering principle of unloading the foot sole. The design geometry of the footwear (insole, outer sole, rocker bottom attached to outer sole for healing footwear), material hardness, density and material to be used are determined by three dimensional finite element stress analysis of foot-footwear composite model, which gives the least normal and shear stresses at the foot sole, thus preventing foot sole ulcers as well as healing of ulcers in any part of the foot sole and healing 5 to 6 times faster than by existing footwear used by diabetic patients. Statement of invention: A novel diabetic footwear for prevention of foot sole ulcers said footwear comprising of new sandal and shoe for prevention of diabetic foot sole ulcers, the new sandal for prevention of foot sole ulcers comprising appropriate thickness, hardness and density micro cellular rubber (MCR) insole, appropriate thickness hardness and density light rubber outer sole, a welt or border around the straps, adjustable front and back straps with Velcro and metal D-ring to adjust the straps to suit the size of the foot, the inner side of the straps lined with soft leather to reduce friction between the upper part of the foot and the straps, the new shoe for prevention of foot sole ulcers having extra depth shoe upper to accommodate appropriate thickness insole, comprising appropriate thickness, hardness and density micro-cellular rubber (MCR) insole, appropriate thickness, hardness and density light rubber outer sole, soft flexible shoe upper, sufficiently broad in the fore-foot region to accommodate toes comfortably, provided with small holes in the front portion of,shoe upper for proper air circulation; shoe upper provided with soft leather inner lining to minimize fiiction between foot and footwear; the shoe held on the foot appropriately with the help of laces, both sandal and shoes for prevention of foot sole ulcers, available in appropriate colours, sizes for ladies as well as for men, This invention footwear comprising of new sandal and shoe for prevention and healing of diabetic foot sole ulcers, the new type of sandal for prevention of diabetic foot sole ulcers, shown in Fig. 5, comprising appropriate thickness, hardness and density micro-cellular rubber (MCR) insole, appropriate thickness, hardness and density light rubber outer sole, a welt or border around the straps, adjustable front and back straps (going around the rear part of the foot) made of flexible leather attached with Velcro and metal D-ring to adjust the straps to suit the size of the foot; the inner side of the straps lined with soft leather to reduce friction between the upper part of the foot and the straps; available in appropriate colours, sizes for ladies as well as for men, The new type shoe for prevention of diabetic foot sole ulcers, shovm in Fig. 6, having extra depth shoe upper to accommodate appropriate thickness insole, comprising appropriate thickness, hardness and density micro-cellular rubber (MCR) insole, appropriate thickness, hardness and density light rubber outer sole, soft flexible rubber shoe upper, sufficiently broad in the fore-foot region to accommodate toes comfortably, provided with small holes in the front portion of shoe upper for proper air circulation; shoe upper provided with soft leather inner lining to minimize friction between foot and footwear; the shoe held on the foot appropriately with the help of laces, available in appropriate colours, sizes for ladies as well as for men, BRIEF DESCRIPTION OF DRAWINGS The accompanying drawings are intended to provide further understanding of the invention and is incorporated in and constitute a part of the invention. The drawings illustrate an embodiment of invention and together with the description illustrate principle of invention. The drawings should not be taken as implying any necessary limitation on the essential scope of invention. The drawings are given by way of non-limitative example to explain the nature of the invention. For more complete understanding of the instant invention reference is now made to the following description taken in conjunction with accompanying drawings. The various features of novelty which characterize the invention are pointed out specifically in the claims which forms part of the description. For a better understanding of the invention, its operating advantage, specific objects obtained by its use, reference should be made to the drawings and descriptive matter in which these are illustrated and described as preferred embodiments of invention. Referring now to drawings, where like numerals designate identical or corresponding parts throughout the referred views. Figure 1 of the drawings shows prior art shoe (available in the market) Figure 2 of the drawings shows prior art shoe (available in the west; to be made individually) Figure 3 of the drawings shows prior art sandal (available in Indian market) Figure 4 of the drawings shows prior art sandal (available in Indian market) Figure 5 of the drawings shows new type of sandal. Figure 6 of the drawings shows new type of shoe. Figure 1 of the drawings shows prior art shoe (available in the market) with hard outer sole (1), with thin medium hard insole and leather upper (2) with lace to properly hold the foot in shoe for use by diabetic patients for prevention of foot sole ulcers, according to prior art. Figure 2 of the drawings shows prior art shoe (available in the west; to be made individually) with a hard outer sole (1), medium hard thin insole and a slightly thicker insole in the medial arch region (2), leather upper with lace (3), and a hard triangular projection (4) fitted to the bottom fi^ont portion of the outer sole, to be used by diabetic patients for healing of foot sole ulcers in the fore-foot region only, according to prior art, Figure 3 of the drawings shows prior art sandal (available in Indian market) with thin hard rubber insole (1) and hard rubber outer sole (2), front leather strap (3) to hold the big toe and wide back leather strap (4) connected to the front strap, to be used by diabetic patients for prevention of foot sole ulcers, according to prior art. Figure 4 of the drawings shows prior art sandal (available in Indian market) as 'Dia-sole' for 'relief of diabetic patients' with thin insole in the fore-foot part and very thin insole in the heel part of the foot (1) made of micro-cellular plastic (MCP), supported by very hard moulded plastic outer sole (2) with back (3) and front leather straps (4); both straps fitted with Velcro, this footwear without the help of buckle on the Velcro strap caimot be made to hold the foot within the footwear with appropriate grip and therefore gives rise to rubbing action between the foot and the strap which could result in ulcers in the upper part of the foot, to be used by diabetic patients for prevention of foot sole ulcers, according to prior art. Figure 5 of the drawings shows new type of sandal comprising of appropriate thickness, hardness and density micro-cellular rubber (MCR) insole (1), appropriate thickness, hardness and density light rubber outer sole (2), a welt or border around the straps (3), adjustable front strap (4) and back straps (5) going around the rear part of the foot made of flexible leather, attached with metal D-ring (6) and Velcro (7), to adjust the straps to suit the size of the foot; the inner side of the straps lined with soft leather to reduce friction between the upper part of the foot and the straps, available in appropriate colours, sizes for ladies as well as for men, for use by diabetic patients for prevention of foot sole ulcers, according to the present invention Figure 6 of the drawings shows new type of extra depth shoe to accommodate appropriate thickness, hardness and density micro-cellular rubber insole, comprising appropriate thickness, hardness and density light rubber outer sole (1), appropriate thickness, hardness and density micro-cellular rubber (MCR) insole (2), soft flexible leather shoe upper (3), sufficiently broad in the fore-foot region to accommodate toes comfortably, provided with small holes in the front portion of shoe upper for proper air circulation; shoe upper provided with soft leather inner lining to minimize friction between foot and footwear; the shoe held on the foot appropriately with the help of laces, available in appropriate colours, sizes for ladies as well as for men, for use by diabetic subjects for prevention of foot sole ulcers, according to the present invention. The inventions have been explained in relation to specific embodiment. It is inferred that the foregoing description is only illustrative of the present inventions and the it is not intended that the invention be limited or restrictive thereto. Many other specific embodiments of the present invention v^ill be apparent to one skilled in the art from the foregoing disclosure. All substitution, alterations and modifications of the present inventions which come within the scope of the following claims are to which the present inventions are readily susceptible without departing from the spirit of the invention. The scope of the invention should therefore be determined not with reference to the above description but should be determined with reference to appended claims along with full scope of equivalents to which such claims are entitled. The applicants have made another application for patent being a co-pending application in respect of invention relating to a novel diabetic footwear for healing of foot sole ulcers. We claim 1. A novel diabetic footwear for prevention of foot sole ulcers said footwear comprising of new sandal and shoe for prevention of diabetic foot sole ulcers, the new sandal for prevention of foot sole ulcers comprising appropriate thickness, hardness and density micro cellular rubber (MCR) insole, appropriate thickness hardness and density light rubber outer sole, a welt or border around the straps, adjustable front and back straps v^th Velcro and metal D-ring to adjust the straps to suit the size of the foot, the inner side of the straps lined with soft leather to reduce friction between the upper part of the foot and the straps, the new shoe for prevention of foot sole ulcers having extra depth shoe upper to accommodate appropriate thickness insole, comprising appropriate thickness, hardness and density micro-cellular rubber (MCR) insole, appropriate thickness, hardness and density light rubber outer sole, soft flexible shoe upper, sufficiently broad in the fore-foot region to accommodate toes comfortably, provided with small holes in the front portion of shoe upper for proper air circulation; shoe upper provided with soft leather inner lining to minimize friction between foot and footwear; the shoe held on the foot appropriately with the help of laces, both sandal and shoes for prevention of foot sole ulcers, available in appropriate colours, sizes for ladies as well as for men, 2. A novel diabetic footwear for prevention of foot sole ulcers said footwear of sandal type as claimed in claim 1 has appropriate thickness, hardness and density micro- cellular rubber (MCR) insole, appropriate thickness, hardness and density light rubber outer sole, a welt or border around the straps, adjustable front and back straps (going around the rear part of the foot) made of flexible leather attached with Velcro and metal D-ring to adjust the straps to suit the size of the foot; the inner side of the straps lined with soft leather to reduce friction between the upper part of the foot and the straps; available in appropriate colours, sizes for ladies as well as for men. (i ) A novel diabetic footwear for prevention of foot sole ulcers said footwear of sandal type as claimed in claim 1 wherein the device has the least foot sole stresses. (ii) A novel diabetic footwear for prevention of foot sole ulcere said footwear of sandal type as claimed in claim 1 wherein the device has superior soft inner lining attached to the straps, preventing foot ulcers. (iii) A novel diabetic footwear for prevention of foot sole ulcers said footwear of sandal type as claimed in claim 1 wherein the footwear has superior back strap that can properly hold the foot inside the footwear and thus prevent foot ulcers and also the straps can be adjusted to take care of swelling in the diabetic foot. (iv) A novel diabetic footwear for prevention of foot sole ulcers said footwear of sandal type as claimed in claim 1 wherein the footwear is more efficient because of 3 times lower foot sole stresses than the existing sandals. (v) A novel diabetic footwear for prevention of foot sole ulcers said footwear of sandal type as claimed in claim 1 wherein the footwear is 3 times cheaper than existing sandals and suitable for wash and wear, more durable than the existing sandals. 3. A novel diabetic footwear for prevention of foot sole ulcers said footwear of shoe type as claimed in claim 1 has extra depth shoe upper to accommodate appropriate thickness insole, comprising appropriate thickness, hardness and density micro- cellular rubber (MCR) insole, appropriate thickness, hardness and density light rubber outer sole, soft flexible leather shoe upper, sufficiently broad in the fore-foot region to accommodate toes comfortably, provided with small holes in the front portion of shoe upper for proper air circulation; shoe upper provided with soft leather inner lining to minimize friction between foot and footwear; the shoe held on the foot appropriately with the help of laces; available in appropriate colours, sizes for ladies as well as for men, (i ) A novel diabetic footwear for prevention of foot sole ulcers said footwear of shoe type as claimed in claim 1 wherein the shoe is very efficient since it has 3 times lower foot sole stresses than the existing shoes. (ii) A novel diabetic footwear for prevention of foot sole ulcers said footwear of shoe type as claimed in claim 1 wherein the shoe has superior soft inner linings attached to the shoe upper, preventing foot ulcers. (iii)A novel diabetic footwear for prevention of foot sole ulcers said footwear of shoe type as claimed in claim 1 wherein the shoe has superior toe box having appropriate breadth to accommodate toes comfortably, thus preventing foot ulcers. (iv)A novel diabetic footwear for prevention of foot sole ulcers said footwear of shoe type as claimed in claim 1 wherein the shoe is 10 times cheaper than the existing shoes. 4. A novel diabetic footwear for prevention of foot sole ulcers as described in the description and illustrated by way of figures 5 to 12 of drawings accompanying the complete specification. ' ^ I/

Documents:

1214-che-2004-abstract.pdf

1214-che-2004-claims.pdf

1214-che-2004-correspondnece-others.pdf

1214-che-2004-correspondnece-po.pdf

1214-che-2004-description(complete).pdf

1214-che-2004-drawings.pdf

1214-che-2004-form 1.pdf

1214-che-2004-form 19.pdf

1214-che-2004-form 3.pdf