WO2019138313A1

WO2019138313A1 - Orthopaedic shoe insole

Info

Publication number: WO2019138313A1
Application number: PCT/IB2019/050106
Authority: WO
Inventors: Gytis ABAKEVIČIUS; Valentinas KUŠVIDAS
Original assignee: Uab "Baltic Orthoservice"
Priority date: 2018-01-09
Filing date: 2019-01-07
Publication date: 2019-07-18
Also published as: LT2018002A; LT6674B

Abstract

This invention belongs to the medical field, in particular to special medical insertions (1) for shoes designed for flat feet, club feet and the like. The purpose of the invention is an extension of the product functionality, increase of durability and comfort. The purpose achieved: technical solutions enable the longitudinal arch height and pronation/supination degree to be individually adjusted, the load on separate foot areas to be balanced, the step- shock absorbed and changes to the correction degree applied in the course of the treatment without the use of additional measures. This product provides an adjustment functionality of the foot position allows for such dynamically variable factors as the nature and hardness of the movement terrain to be taken into consideration, as well as other characteristics such as fatigue, minor trauma, etc., which cannot be taken into account when custom-made insoles are produced.

Description

ORTHOPAEDIC SHOE INSOLE

This invention belongs to the medical field, in particular relating to special medical insertions for shoes designed for flat feet, club feet and the like (International classification: A43B 7/14).

These orthopaedic insoles are designed for the adjustment of the foot position support in relation to the static movement, for support of the foot movement direction in relation to its dynamic changes, and for the treatment of certain post-traumatic symptoms and/or some other conditions (foot pathologies - hallux valgus, pes varus, pes valgus, etc.). The left and right feet of a person will frequently differ from the static (longitudinal arch height, foot position) and the dynamic point of view (foot position in different step phases). These differences may be congenital or acquired; therefore, the possibility to individualise the insoles for both feet is important. The insoles may feature special load bearing and/or stress reducing areas for the support of the foot arch, for an even distribution of the weight on the foot and for partial absorption of the step shock.

The possibility to adjust the pronation/supination degree is particularly relevant for athletes, because the optimisation of the foot position with respect to the movement support depends on the nature and hardness of the movement terrain and other characteristics, as well as on the individual athlete’s movement characteristics. These can be either permanent (developed), such as congenital or acquired clinical conditions that require conservative medical attention and movement technique; or dynamically variable such as a physical condition, fatigue, minor trauma, etc. Therefore, even though footwear manufacturers offer shoes with different pronation or supination degrees, their individual adjustment to a particular foot is ensured with the help of orthopaedic insoles, and the individually adjusted orthopaedic insoles do not allow for the dynamically variable foot interaction to be adapted with the movement support.

The orthopaedic shoe insoles are custom made according to the clinical and anatomical data of every patient, with the help of mechanical formation, 3D milling and popular 3D printing technologies:

With the help of traditional technologies, they are produced by the layering of materials of different densities. This allows the foot load to be evenly balanced, reducing the load at painful foot points and absorbing the step shock; but on the other hand, it reduces the stability of the foot’s contact with the movement support and overloads the foot muscles. Also, under the weight of a person, the soft insoles become compressed; therefore, their corrective effect on the foot position with respect to the movement support become less prominent, and their mechanical properties change during the course of wearing the insoles. Thus, people, who are actively engaged in sports activities prefer using firm shoe insoles.

The 3D printing technology used in the manufacturing of orthopaedic insoles allows physical and functional characteristics to be derived (lightweight, thin, porosity), which the traditional production methods (manual shaping, programme-controlled milling, etc.) cannot offer.

The standard 3D printing manufactured orthopaedic insole with integrated technical solutions allows for easy adjustments to meet customised needs. There are multiple adjustment possibilities. The medical gear comprises a plantar insole surface, bottom support housing, fixtures facilitating the adjustment of the longitudinal arch height and the pronation/supination degree, and a shock absorbing structure.

Known DASHAMERICA, INC. (see Patent No. US8667716B2) and FOOT SCIENCE INTERNAT LTD (see Patent No. W02006068513A1) insoles provide the possibility to adjust the height of the support area, the corrective direction and the degree by attaching and/or inserting additional elements into the insole structure. Such a method of correction is inconvenient and imprecise, as the additional elements do not allow the corrective level to be accurately determined, while the insole adjustment is labour intensive and requires additional materials and equipment (for gluing and polishing). Furthermore, because every single correction requires different corrective elements, some of the elements that are including in the insole set remain unused and preclude the implementation of the zero-waste manufacturing. Moreover, these elements are frequently lost, and thus the corrective functions of the insoles remain unrealised, or the specialised customer service centre must be contacted.

The known KENT COMMUNITY HEALTH TRUST insoles (see Patent No. EP2923287A1) are custom-made using 3D printing and feature the layered structure characteristic of 3D printing. The main features of these insoles are the shock absorbing surface (dome shapes) under the ball of the foot, the wave shapes of the plantar surface, cylindrical retro capital pads for the transverse arch and the structure of several different rigidity regions.

The prototype surface is divided into several regions of different rigidities, which are ensured by the use of materials with various degrees of density and firmness. This is not a novel solution in the production of traditional insoles nor an advantage that allows regions of different degrees of firmness to be derived. The available 3D printing technologies allow for the mechanical integration of separate shoe insole components made of materials with different levels of density and firmness; however, this technological / structural solution is flawed in comparison to the homogeneous 3D printing - the variable density of the materials increases the possibility of joint separation and mechanical damage, and undermines the product’s durability.

This manufacturing process of insoles requires both clinical and anthropometric 3D foot data or 3D templates, which can be individualised according to the personal client information. This means that this type of insole requires personalised customer services, 3D scanning equipment, individual product modelling and materialisation with the help of 3D printing. This makes the production of such products possible only by larger companies engaged in producing secondary orthotic technical devices, the costs of which are several times higher.

The prototype structure does not provide an adjustment functionality for a correction of the foot position in respect to the movement support, and it does not allow for the consideration of such dynamically variable factors as the nature of the support, the physical condition of a patient, fatigue, minor trauma, etc., which cannot be taken into account when producing custom-made therapeutic footwear insoles. These insoles are also not provided with foot position adjustment mechanisms in regard to the movement support. Therefore, the restoration of the foot position into a neutral one following the correction or adjustment of the corrective functionality in the case of fatigue and in consideration of the type of footwear is impossible. For example, upon the identification of incorrect foot dynamics following a baropodographic examination, it is impossible to adjust the foot position using the same insoles and the production of new inserts is then required. The purpose of the invention is an extension of the orthopaedic insole’s functionality and an increase of its durability and comfort, in particular due to the product’s homogeneous structure, by making it a standard orthopaedic insole which allows for an easy adaptation to the patient’s foot, individualisation of the longitudinal arch height, optimal arch support, reduction of the step shock, precise and simple adjustment of the corrective properties of the insole and, in the course of treatment or in the event of a replacement of the footwear, an adjustment of the corrective level without the use of additional elements, foot scanning or extra modelling. The other currently available solutions do not allow the corrective function of the insoles to be adjusted in the event of changes in the dynamically variable factors (nature of the movement support, patient’s physical condition, fatigue, minor traumas, etc.) or they require the use of additional materials, attachments or special tools for the insertion of the said elements between the insole layers or for the adhesion and polishing of the auxiliary materials. Such an insole adjustment becomes complicated and demands a knowledge of the product’s manufacturing technologies, as well as being impractical with respect to the storage of the extra elements.

This purpose is realised by creating a standard (adapted for standard shoe sizes and mass production) orthopaedic footwear insole of a homogeneous structure which, with the help of its technical constituents, allows for a simple and quick adjustment of the foot position support in relation to the static and dynamic movement, as well as the individualisation of the longitudinal arch height and an individual adjustment of the pronation/supination degree, while at the same time providing an adjustment functionality for the correction of the foot position correction in relation to the movement support and also allowing for the consideration of such dynamically variable factors as the nature the movement support, the physical condition of a patient, fatigue, minor trauma, the type (application) of shoes, etc., all of which cannot be taken into account when producing custom-made orthopaedic footwear insoles. The insole structure also allows to the load on the individual foot regions to be balanced and the step shock to be absorbed. In addition, the invention enables the user, personally or with the help of a specialist, to adjust the shoe insoles to respond to the variable factors affecting the optimal foot position with respect to the movement support and offers a functional alternative to custom-made insoles. This allows for a significantly higher accessibility of the orthopaedic insets by the users to be ensured in terms of the price and delivery term, while offering additional comfort through the use of 3D printing (the product volume is reduced allowing to it to be used in different types of shoes, as well as a lower weight, increased flexibility and better breathability). The invention also expands the circle of specialists that can offer orthopaedic insoles to patients to include kinesitherapists, podiatrists, sports physicians and trainers, who do not have access to the equipment enabling them to produce individually adapted orthopaedic insoles, and it enhances the competition between the service suppliers on the market and ensures an efficient use of the insurance funds (due to a transition from custom-made insole to standard insoles with individualised functionalities and increased competition on the insole supply market), because the acquisition of most orthopaedic insoles is financed by public funds.

We’re providing a standard orthopaedic footwear insert with integrated multiple foot position adjustments in relation to the movement support is made my means of 3D printing from a rigid and fatigue-reducing polymer. The orthopaedic insole has a homogeneous structure and does not require assembly, additional elements or knowledge of the respective technologies. This insole solves the aforementioned problems and it does not require the costly and lengthy manufacturing of custom-made insertions. It enables the pronation/supination degree and height of the longitudinal arch to be adjusted precisely in any type of footwear, including both casual and sports shoes, with the already existing pronation or supination. The accuracy of the insole solution that minimises the interior spatial demands of the shoe is achieved by the application of an additional production technology, which enables the application of the insole in a wide range of shoe types.

In comparison with the traditional production methods, the structures used in the insole plantar surface are reduces in weight by several times. The triangular, square and pentagon-shaped cells, or other infinitely repeatable shaped cells (honeycomb structure) are formed in a repeating order and are placed next to each other over the plantar surface, the area of which, depending on the preferred level of firmness, can vary between 1 and 10 mm , making the insole flexible and breathable. If the cell area is 2

reduced to less than 1 mm , the surface will lose its ventilation properties; whereas if it is increased to over 10 mm , the rigidity of the structure and its wear resistance will be compromised. Therefore, this range is optimal and allows reduced sweating, higher comfort, and proper support and durability to be ensured.

The rigidity of the insole surface can be adjusted by reducing or increasing the density of the cellular structure, depending on the firmness that is preferred. This way, the effect of a different surface rigidity in the support elements of different foot regions is derived by using the same material, which is equivalent to the layering of materials of different densities and rigidities that is performed using the traditional insole production technologies.

The bottom support structure of the insole is firm with respect to the base; however, it is flexible in all other directions. This property allows for an even distribution of the foot load for users with a higher weight without compromising the flexibility. The bottom insole structure comprises a square and rectangular shape, with elongated or rounded shock absorbers of different sizes, rests and long supporting walls. These structures may be spread over the entire plantar surface of the insole and under the centre of the foot support weight when transferring the weight from one step phase to another (longitudinal arch, external arch, transverse arch and heel edges). The sectional area of the shock absorbers and rests, depending on the preferred level of firmness, may vary between 1 and 25 mm . Absorbers with a cross-section of less than 1 mm will lose their support and shock absorbing properties, while those with a cross-section higher than 25 mm are not practical with regard to weight and rigidity. For this reason, the distribution density of the shock absorbers may vary between 1 and 30 cm . The elongated supports are long and narrow to ensure a sufficiently large area of the rests. The inclination of these rests and the absorbers is 30-90 degrees in relation to the base. The 90 degree angle ensures the maximum firmness and minimum shock absorption, while the laterally inclined absorbers perform a shock damping function. An angle lower than 30 degrees reduces the shock absorbing properties to the maximum while making the use of such absorbers functionally inefficient. These absorbers ensure the absorption of step generated shock energy and seek to protect the joint ligaments from premature wear, as well as adding comfort and softness. The insole is produced in different standard sizes; thus, it can easily be adapted to different foot sizes and offers an alternative to custom-made therapeutic shoe insoles without the expensive production process involving multiple stages. It also ensures extra comfort (the help of 3D printing enables a smaller product volume allowing for its application in different types of shoes, with a reduced weight, increased flexibility and breathability), which the traditional insole technologies cannot offer. The insole structure allows the shape of the tip and the insole length to be adjusted to fit the available shoe type with the help of ordinary scissors. In this way, people with wider feet can reduce insoles of a larger size and leave the required width in the metatarsal area, making the insoles usable for a wider circle of consumers. The individualised insoles featuring all or part of the aforesaid properties can also be exclusively made for those possessing non-standard feet.

The medial insole section features a longitudinal arch height adjuster, which allows the arch height to be adjusted by a rotational movement about the rotary axis. The adjusting mechanism comprises a rotating bottom and a fixed top screw, with the denticular surface allowing for the rotation in one direction only in relation to each another; therefore, rotating the bottom screw in one direction will increase the space between the screw tops, while if an attempt is made to rotate it in the opposite direction, the denticular surface will block the movement. By rotating this mechanism, the transverse arch height can be elevated by 5-15 mm, depending on the insole size. This is an optimal height sufficient to perform corrections in the presence of minor pathologies. The denticular adjuster structure performs a locking function at the determined height and prevents the adjuster from reducing the height in the process of wearing the shoes. The maximum height value is achieved by a continued height increase action which, if exceeded, will reset the adjuster to the initial position. In this way, a precise height regulation may be achieved as many times as necessary, while the insole is adjusted to the individual needs of the users.

The metatarsal region is provided with a flexible slanting device regulating the pronation/supination degree (height) of the anterior region of the foot, allowing for an individualised adjustment of the pronation/supination height and a modification of the corrective properties of the insole. With the help of the rotating axis in the front part of the insole, the adjuster acts as an elevating mechanism. By rotating the adjuster in a clockwise and counter-clockwise direction, the conical surface changes the thickness of the lateral or medial insole side. Depending on the insole structure, this adjuster can be locked in 4 to 18 positions. A lower number of positions would not ensure the sufficient functionality, while a higher number thereof would be redundant. The maximum height value, depending on the insole size, can vary between 1 and 10 mm. The maximum value of 10 mm is sufficient for the reconstruction of a minor foot pathology; in other cases, where the pathologies are more complex, individually adapted insoles may be produced depending on the type of pathology. This ratio of the number of positions and heights ensures the possibility of a precise adjustment of the anterior foot region inclination. The adjustment of the pronation/supination performs the corrective function and enables the corrective degree to be changed throughout the course of treatment. The correctly adjusted height of the insole arch and the pronation/supination can also ensure an even distribution of the weight and load over the entire foot surface and will reduce stress on the metatarsus and arch regions.

Descriptions of the drawings: Fig. 1 Bottom part of the insole; Fig. 2. Anterior and posterior parts of the insole; Fig. 3. Medial and lateral parts of the insole; Fig. 4. Insole medial view; Fig. 5. Insole lateral view; Fig. 6. Insole bottom view; Fig. 7. Pronation/supination degree regulation insert; Fig. 8. Support walls and shock absorbers.

The bottom part of the insole (1) is comprised of the structural base (2), where the anterior (3) and posterior (4) parts are connected with the breathable plantar surface (5), and the medial part (6) with the arch height adjustment mechanism (7). In the lateral part (8), the plantar insole surface (5) is connected with a number of spring-like structural elements (9), where the direction, size and thickness of these depends on the insole size and the preferred shock absorbing properties. The flexible pronation/supination adjustment mechanism (11) is attached to the pronation/supination adjustment axis (10) in the anterior part (3) of the plantar surface (5). The furthermost plantar surface (5) region features the corrective zone (12) allowing the insole length and width to be adjusted by cutting or filing off some parts. The insoles are selected according to a patient’s foot length and width. Consequently, the correction of the front insole part is performed in the shape corrective zone (12), which can be cut or filed off, thus adapting the insole shape to the shape of the shoe tip. The next step is the adjustment of the pronation/supination of the anterior foot position. The foot adjustment mechanism (11) can be rotated to elevate the plantar surface (5) in relation to the support. After the adjustment of the anterior part of the foot, the medial arch height must be verified - the insole must be placed on a hard surface, and the patient must then place his/her foot on the insole plantar surface (5) while the longitudinal interior arch adjuster (7) is set in the lowest position. The interior insole arch must be resting on (supporting) the interior arch, without causing discomfort or pain. If the interior insole arch does not touch the foot, the correction is insufficient and the longitudinal arch height must be adjusted. The correction of the insole interior arch is carried out by rotating the arch height adjuster (7) in the bottom part the required number of steps to elevate the plantar surface (5) with the help of a hex key. After the adjustment of the interior arch height, the springs (9) in the lateral part (8) will automatically adapt to a lowered exterior arch and an increased load, thus activating the self-adjustment function of the exterior arch of the insole. The springs (9) in the lateral part (8) of the insole also act as shock absorbers - the separate spring elements cushion the foot and dampen the step shock energy. This allows the feet to be protected against harmful impacts and adds a feeling of comfort and softness.

In comparison with the prototype, the structure of the invention is characterised by higher functional possibilities and better stability, and offers a higher degree of wear comfort. The correctly adjusted height of the insole arch and the pronation/supination can guarantee an even distribution of weight and load over the entire foot surface and can reduce stress on the metatarsus and arch region. The adjustment of the pronation/supination also performs a corrective function and enables the corrective degree to be changed throughout the course of treatment. The springs provided in the lateral or other parts of the insole will protect the locomotor system from the adverse effects of step shock. The invention ensures the product’s adaptability to dynamically variable factors, such as the nature of the movement support, the patient’s physical condition, fatigue, minor traumas, the type (application) of shoes, etc. It also prolongs the product’s service life and enhances its accessibility in terms of the distribution/application point, price and terms of supply.

Claims

1. The orthopaedic shoe insole is comprised of a structural base, where the front and back parts are connected by a plantar surface, w h e r e i n the plantar surface is made of triangular, square and pentagon-shaped cells, or other geometrically shaped cells placed in a repeated omament-like sequence next to each other with an area between 1 and 10 mm , depending on the preferred rigidity, and where the area ratio of the cells and walls varies between 1: 1 and 1:50, forming both cells with the same area and shape and cells with different shapes and areas, allowing a structure with variable rigidity to be derived.

2. The orthopaedic shoe insole, according to Claim 1, w h e r e i n the medial insole part features the foot arch adjusting mechanism comprised of a rotating bottom and fixed top screw, the denticular surface of which allows the rotation to occur in one direction only in relation to one another, also rotating the bottom screw in one direction will increase the space between the screw tops, while if an attempt is made to rotate it in the opposite direction, the denticular surface will block the movement.

3. The orthopaedic shoe insole, according to Claim 1, w h e r e i n the metatarsal region features a flexible anterior foot region pronation/supination height adjustment mechanism that comprises a rotating variable thickness plane and its position lock, allowing for the individual correction of the pronation/supination height and direction, that is attached to the insole plantar surface via the locking axis which can be fixed in at least 4 positions to change the height of the pronation or supination.

4. The orthopaedic shoe insole, according to Claim 1, w h e r e i n a bottom insole structure comprises shock absorbers of different sizes with a polygon or oval-shaped cross-section, as well as the supporting walls, and where these structures are provided both under the entire insole plantar surface and in the areas demanding foot support (longitudinal arch, external arch, transverse arch and heel edges), while the cross- sectional area of the absorbers, depending on the preferred rigidity, can vary between 1 2

and 25 mm , with a density of between 1 and 30 units per square metre, and with their inclination in relation to the base comprising an angle of 30-90 degrees.

5. The orthopaedic shoe insole, according to Claim 1, w h e r e i n it features a homogeneous structure not requiring an additional assembly or auxiliary elements.

6. The orthopaedic shoe insole, according to Claims 1-5, w h e r e i n all the aforesaid properties also apply to the production of individualised insoles exclusively for non standard feet, by modifying the shape of the plantar surface and individually selecting the supporting and shock absorbing elements, as well as their quantity and locations.