US20040194348A1

US20040194348A1 - Heat malleable orthotic shoe insert

Info

Publication number: US20040194348A1
Application number: US10/409,539
Authority: US
Inventors: Todd Campbell; Russell Davis; William Guthrie
Original assignee: Campbell Todd D; Davis Russell C; Guthrie William Y
Current assignee: Millipede Inc
Priority date: 2003-04-07
Filing date: 2003-04-07
Publication date: 2004-10-07

Abstract

The invention provides an orthotic insert for an article of footwear, which includes a cupped heel portion, the cupped heel portion having a concave upper bearing surface that extends above a most posterior cephalad portion of a calcaneous; and a heat-malleable mid-foot portion continuously coupled to the heel portion, the mid-foot portion having a medial longitudinal arch and a heat-deformable upper bearing surface. The invention also provides a method of treating a podiatric condition with an orthotic insert and a method of manufacturing a heat-malleable orthotic insert for an article of footwear.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

TECHNICAL FIELD

The present invention relates generally to orthopedic devices, and more particularly to a customizable orthotic shoe insert used to abate and prevent foot and related ailments.

BACKGROUND INFORMATION AND DISCUSSION OF RELATED ART

Custom orthotics for feet typically contain a relatively rigid, resilient base comprising a low-rise heel portion and an arch portion, contoured to fit the plantar or bottom surface of the foot. Orthotic devices may be inserted into footwear to reduce pronation of the foot and to provide a therapeutic and corrective effect for foot ailments such as plantar fasciitis, cuboid syndrome and tissue trauma. Custom-made orthotics are generally formed from hard plastics by using a mold or extensive measurements of an individual's foot, and modified as needed to provide prescribed corrections by a podiatrist. Unfortunately, custom orthotics typically fit into only one or a few pairs of shoes, and are too expensive for a wide variety of shoes that might be part of a person's wardrobe. Because of the expense, orthotic devices are often used only after serious degradations of a foot problem and severe increases in foot pain. As a foot condition improves, prescribed orthotics may require alterations with less correction or be discarded altogether. Although highly beneficial in correcting early onsets of podiatric conditions, custom orthotics for a child may be considered cost prohibitive, with frequent size alternations needed due to rapid growth of the feet and changing body physiology of the child.

Some recent efforts have been made to correct foot problems with firmer and higher durometer materials added to the arch area and around the heel of the foot. These devices, most of them custom-molded for the foot, are designed to resist pronation and to distribute weight-bearing stresses to areas of the foot that can better tolerate such stresses, thus maximizing comfort and minimizing trauma to the sole of the foot. Such an orthotic device may provide a padded surface that is shaped to conform to the contours of a particular foot. Some corrective orthotic devices have been designed to guide and restrict the motion of joints of the foot in order to improve gait efficiency and to reduce the stresses imposed on lower extremity anatomical structures during walking, running and standing.

Currently, there are orthotic shoe inserts that work to give a more even weight distribution to take pressure off of sore spots such as the ball of the foot, corns in between toes, and bunions. Similar orthotic devices also aid other people suffering with foot problems such as heel spurs, shin splints, foot pain, Achilles tendonitis, calluses, and Morton's Neuroma. Young children may be fit with these devices to help with biomechanical conditions such as Sever's Disease, Osgood-Schlatters, and growing pains.

Unfortunately, most customized shoe inserts require molding of the foot and fabrication of the device with a delay of several weeks between the taking of measurements for an orthotic insert or insole and the arrival of the new customized shoe inserts or insoles. Many of the molding methods involve the injection of moldable and sometimes chemically reactive material around the foot and/or the application of heat to the material surrounding the foot.

Several exemplary approaches have been taken in constructing custom-fitted orthotic footwear. In one approach, a chemical reaction is initiated in a formable material in a footbed. The person then steps into the footwear or shoe to form an impression on the material, and then the material is allowed to cure. U.S. Pat. No. 3,968,577 illustrates a system in which an impression of the foot is made, and the material is cured or set either pursuant to room temperature vulcanizing or by being heated in an oven for an extended period of time. Other patents disclose a shoe or sandal having a bottom layer of a thermoplastic material that is softened by heat and an impression is made by the wearer's foot. Various foot orthotics using material formable by chemical reaction or heat and related information are described in U.S. Pat. No. 3,325,919 by Robinson; U.S. Pat. No. 3,641,688 by von den Benken; U.S. Pat. No. 3,895,405 by Edwards; U.S. Pat. No. 3,968,577 by Jackson; U.S. Pat. No. 4,128,951 by Tansill; U.S. Pat. No. 4,413,429 by Power; U.S. Pat. No. 4,428,089 by Dawber et al; U.S. Pat. No. 4,433,494 by Courvoisier et al; U.S. Pat. No. 4,463,761 by Pols et al; U.S. Pat. No. 4,503,576 by Brown; U.S. Pat. No. 4,510,636 by Phillips; U.S. Pat. No. 4,520,581 by Irwin et al; U.S. Pat. No. 4,868,945 by DeBettingnies; U.S. Pat. No. 4,888,225 by Sandvig et al; U.S. Pat. No. 4,901,390 by Daley; U.S. Pat. No. 5,101,580 by Lyden; and U.S. Pat. No. 5,203,793 by Lyden.

U.S. Pat. No. 5,829,171 discloses a prefabricated heat-softenable insole with a built-in electric heater or heat member, which is limited in its ability to change shape to provide orthotic benefit. One problem with this insert and other relatively planar shoe inserts is that there is no allowance for the insert to compensate for foot problems such as the tendency to over-pronate or supinate. A unitary orthotic device, which is designed for significant control of foot motion and realignment and helps prevent excessive foot pronation, is disclosed in utility patent application no. 2002/0162250, entitled “Unitary Orthotic Insert and Orthopedic Insole”, by Guthrie et al, filed Apr. 30, 2002, the contents of which are hereby incorporated by reference.

An improved orthotic shoe insert would incorporate control of foot motion and realignment such as that described in the previously mentioned device, and would provide a greater customization to the foot of an individual. A desirable semi-customized orthotic insert can conform more exactly to a foot and provide even greater protection while reducing stress and pressures on the foot. A beneficial orthotic device helps alleviates pain and further deterioration of foot problems such as excess pronation, heel spurs, shin splints, foot pain, Achilles tendonitis, bunions, and calluses.

The desirable orthotic shoe insert could be fit into a shoe during one office visit to a medical foot specialist or at the convenience of the wearer. It would be fit to many types and sizes of adult and children's shoes and be useful in a variety of work, sport, or dress shoes that a person might wear. A desirable semi-customizable orthotic insert would provide many of the benefits of a fully customized orthotic insert or insole without the time or expense of a customized orthotic device.

Therefore, an object of this invention is to provide a semi-customizable orthotic shoe insert that provides the desirable improvements, as well as to overcome the deficiencies and obstacles described above. More specifically, the purpose of the current invention is to provide a semi-customizable orthotic shoe insert with the ability to control the subtalor joint and realign the foot and anklebones to their neutral position, as well as to provide a malleable insert that may be individually fit, site-molded to a foot, and ready to wear shortly after fitting.

BRIEF SUMMARY OF THE INVENTION

One aspect of the invention provides an orthotic insert for an article of footwear, including a cupped heel portion, the cupped heel portion having a concave upper bearing surface that extends above a most posterior cephalad portion of a calcaneous; and a heat-malleable mid-foot portion continuously coupled to the heel portion, the mid-foot portion having a medial longitudinal arch and a heat-deformable upper bearing surface. The orthotic insert is used in a method of treating a podiatric condition where a foot is strapped into a neutral position, the heat-malleable orthotic insert is heated, the strapped foot is pressed into the heat-malleable orthotic insert, and the insert is cooled to an ambient temperature. A themochromatic indicator may be incorporated into the mid-foot portion of the orthotic insert.

Another aspect of the invention is a method of manufacturing an orthotic insert for an article of footwear, which includes providing an orthotic insert mold, injecting an injection-molding compound into the orthotic insert mold, releasing the orthotic insert from the orthotic insert mold, and inserting a heat-malleable material into at least the mid-foot portion of the orthotic insert. A thermochromatic indicator may be inserted into the mid-foot portion of the orthotic insert.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The following drawings are shown with left feet, left shoe inserts, and left shoes, and it should be understood that the right foot, inserts or shoes are substantially mirror images of the left side. It should also be understood that the use of the word shoe, in the context of this document, is intended to be synonymous with nearly all articles of footwear, including but not limited to boots, sandals, open-toe shoes and closed-toe shoes. [0016]
Characteristics and advantages of the invention will become apparent from the following detailed descriptions of particular but not exclusive embodiments, illustrated by way of non-limitative examples in the accompanying drawings, wherein: [0017]
FIG. 1 illustrates a side view and a top view of a human foot; [0018]
FIG. 2 illustrates a perspective view of a foot, shoe, and an orthotic insert, the latter assembled with a pre-molded heel-cup piece and a heat-malleable mid-foot piece, in accordance with one embodiment of the current invention; [0019]
FIG. 3 illustrates a perspective view of a foot, shoe, and orthotic shoe insert, the latter assembled with a heat-malleable mid-foot piece on top of a full-length pre-molded piece, in accordance with one embodiment of the current invention; [0020]
FIG. 4 illustrates a perspective view of an orthotic shoe insert with a pre-molded piece and heat-malleable mid-foot piece, in accordance with one embodiment of the current invention; [0021]
FIG. 5 illustrates a cross-sectional view of an orthotic shoe insert with a heat-malleable mid-foot piece and a pre-molded heel-cup piece, in accordance with one embodiment of the current invention; [0022]
FIG. 6 illustrates an inside of an orthotic shoe insert from a perspective view, in accordance with one embodiment of the current invention; and [0023]
FIG. 7 is a flow diagram of a method of manufacturing an orthotic insert for a shoe, in accordance with one embodiment of the current invention; and [0024]
FIG. 8 is a flow diagram of a method of treating a podiatric condition, in accordance with one embodiment of the current invention.[0025]

DETAILED DESCRIPTION OF THE INVENTION

The orthotic shoe insert of the current invention has a heat-malleable piece in at least the mid-foot area that may be customized to a person's foot. The orthotic insert helps to cooperatively redistribute the normally greater weight-generated forces applied to the inner and bonier regions of the heel outwardly toward the outer and fleshier regions of the heel. Additionally, it provides support and stability to affected areas of the foot and reduces subtalar joint motion without substantially affecting the fit of the shoe into which the device is placed. [0026]
The present invention is constructed of a pre-molded polymer piece and a heat-malleable polymer piece. The device is heated to soften the heat-malleable material, and is inserted with an individual's foot into the shoe for which the molded device will be worn. The orthotic insert can be used by a podiatric specialist who straps a patient's foot, for example, with the low-Dye strap into a neutral position, after which the patient's foot is inserted into the shoe and held into that neutral position until the polymer cools and hardens. Thus the orthotic insert is fit to both the patient and the shoe with which it will be worn. The shoe insert with its deep heel cup and heat-malleable material may assist in inverting the subtalar joint to a position of slight inversion and simultaneously, plantar-flexing the first ray to lock the midtarsal joint during ambulation. Thus, the present invention reduces excessive pronation, a condition that often leads to foot injury. The therapeutic device is capable of relieving foot pain and biomechanically correcting or alleviating misaligned conditions in a foot. [0027]
The semi-customizable insert may help prevent or provide relief from common foot problems such as heel spurs, arch pain, metatarsalgia (ball-of-foot pain), bunions, hammertoe, arthritis, neuromas, diabetes foot, plantar fasciitis, cuboid syndrome, tendonitis, stress fractures, shin splints, a pronation condition and other ailments of the foot, leg, and lower back. Although the invention may serve as an aid in the recovery from a foot ailment, the invention may also serve to prevent the onset or reoccurrence of various foot problems and athletic injuries. [0028]
The insert includes a high-rise heel-cup portion that absorbs shock during heel strikes, while providing support to the proximal, distal and posterior of the calcaneous. The insert includes a heat-malleable material in at least the mid-foot portion that cooperates with the heel portion to stabilize and support the foot while preventing excessive pronation, and provides a therapeutic characteristic for a podiatric condition. [0029]
The deep heel-cup portion of the present invention wraps around the heel of the foot and extends above a posterior portion of the heel bone proximal to the Achilles tendon. The mid-foot portion of the insert is continuously coupled to the cupped heel portion. The pre-molded piece forms at least the heel-cup portion, but it may extend to the mid-foot portion and even to an optional forefoot portion. The heat-malleable material is used for at least the mid-foot portion, although it can be extended into the heel-cup area and the forefoot area. [0030]
The mid-foot portion is usually pre-shaped with a curvilinear upper bearing surface and a medial longitudinal arch support to aid in the support of the medial longitudinal arch of the foot. The upper surface of the mid-foot portion may include a minor arch to support the lateral longitudinal arch near the outside of the foot, and a minor arch to support the transverse arch perpendicular to the medial longitudinal arch and the lateral longitudinal arch of the foot. The mid-foot portion extends from the heel cup towards the heads or anterior ends of the metatarsal bones. This general shape of the heat-malleable mid-foot portion can better conform to an individual's foot after its material is heated to a point where it can be further shaped with the downward pressure of a foot. [0031]
The cupped heel portion and the mid-foot portion coordinate to help realign the rearfoot to avoid overpronation and reduce stress on the Achilles tendon. Excessive pronation renders the gait of a walker or runner less efficient, and is a source of lower extremity pathologies, including muscle tiredness and inflammation, foot and knee joint pain, tendonitis, ligament strain, and even neurological damage. [0032]
The actual dimensions of the orthotic insert of the present invention will vary depending on the size of the foot, the intended use of the shoe, and other factors. The net result is an orthotic insert that controls pronation, supports the foot, and produces a more stable platform on which and in which the foot ambulates while providing a customizable fit for the mid-foot area. [0033]
FIG. 1 illustrates a side view and a top view of a human foot at [0034] 100. The toes of a human foot are formed by fourteen phalanges. Starting from the inside of the foot, each toe has distal phalanges 102, 104, 106, 108 and 110, middle phalanges 114, 116, 118 and 120, and proximal phalanges 122, 124, 126, 128 and 130. The first phalange or big toe lacks a middle phalange. The forefoot comprises the phalanges and the heads or anterior end of the metatarsals.
The mid-foot includes five [0035] metatarsals 132, 134, 136, 138 and 140. First metatarsal 132, which is the shortest and thickest of the metatarsal bones, bears the most weight and plays the most important role in propulsion. First metatarsal 132 also provides attachment for several tendons. The more stable second metatarsal 134, third metatarsal 136, and fourth metatarsal 138 are well protected with only minor tendon attachments, and thus are not subjected to strong pulling forces.
The mid-foot also includes five of seven tarsal bones: navicular, cuboid, and cuneiform bones. The distal row contains three [0036] cuneiforms 142, 144 and 146 and a cuboid 148. The mid-foot includes five tarsometatarsal joints, which are among multiple joints within the mid-foot itself. Proximally, cuneiforms 142, 144 and 146 articulate with a navicular 150.
A [0037] talus 152 and a calcaneus 154 make up the rear or hind portion of the foot. Calcaneus 154 is the largest tarsal bone, and forms the heel. Talus 152 rests on top of it, and forms the pivot for the ankle.
Toe movements take place at joints that are capable of motion in two directions: plantar flexion and dorsiflexion, as well as abduction and adduction. The remainder of the foot has two movements, inversion and eversion, to which joints of the hindfoot and mid-foot contribute. These complex movements are combined ordinarily with ankle movements and movements of the fibula and tibia. [0038]
Two primary functions of the foot are weight bearing and propulsion, both requiring stability and flexibility. The bones and intervening joints of the foot give flexibility while multiple bones form an arch to support the weight of the body. [0039]
The three arches of the foot are the medial longitudinal arch, lateral longitudinal arch, and transverse arch. The inner or medial longitudinal arch, the highest of the arches, comprises [0040] calcaneus 154, talus 152, navicular 150, cuneiforms 142, 144 and 146, and first three metatarsals 132, 134 and 136. The outer or lateral longitudinal arch, which is lower and flatter than the medial arch, comprises calcaneus 154, talus 152, cuboid 148, and fifth metatarsal 140. At times, fourth metatarsal 138 is included in the lateral arch. The generally hemispherical arc of the transverse arch comprises cuneiforms 142, 144 and 146, cuboid 148, and the bases of metatarsals 132, 134, 136, 138 and 140. The arches of the foot are maintained by the shapes of the bones and ligaments, and supported by muscles and tendons. The lateral arch, medial arch and transverse arch aid the foot in supporting and distributing the weight of a person. During a heel strike, for example, the force on the heel region may exceed three times the normal weight of the body.
When walking, body weight is first placed on the heel, then forward to the ball of the foot. As body weight is applied to the foot, the arches flatten out slightly to absorb the added pressure, spreading out the force and strain across the bones of the foot evenly. As the foot is lifted before taking another step, the arch springs back into its arched position. [0041]
The foot has two primary motions: supination and pronation. Supination is a combination of inward rotation at the ankle, adduction of the hindfoot, inversion of the forefoot, and medial arch elevation. Supination occurs when a heel comes off the ground. Subtalar joint supination involves three simultaneous planes of motion: adduction, inversion, and plantarflexion. As the foot supinates, lateral structures tighten. Continued supination and adduction force may rupture portions of lateral collateral ligaments or avulse these ligaments from their bony attachment sites on the distal fibula, resulting in an ankle sprain. [0042]
Subtalar joint pronation involves three simultaneous planes of motion: abduction of a forefoot, eversion of a hindfoot, and dorsiflexion. Because of the close contiguity of the joints involved, pronation is accompanied by eversion of the heel and internal rotation of the leg and hip. In simple terms, pronation is a motion that occurs when the foot lands on the outside edge and the inner arch collapses as far as it can to absorb shock. [0043]
Overpronation, the maximum range of motion between pronation and supination, is often cited as a cause of leg and foot problems among runners and a contributor to knee, hip and back pain. While pronation is a normal part of a person's gait, it is understood that excessive pronation may be the source of many lower extremity pathologies, including muscle tiredness and inflammation, foot and knee joint pain, tendonitis, ligament strain, and even neurological damage. Excessive pronation may render the gait less efficient since time and effort is wasted in pronating and supinating. [0044]
FIG. 2 illustrates a perspective view of a foot, a shoe and orthotic insert, the latter assembled with a pre-molded heel-cup piece and a heat-malleable mid-foot piece, in accordance with one embodiment of the present invention at [0045] 200. An exemplary orthotic insert has a pre-molded piece 280 and a heat-malleable mid-foot piece 270 that are coupled to each other to form a smooth and continuous upper bearing surface of the orthotic insert. Pre-molded piece 280 has a cupped heel portion whose lower bearing surface substantially conforms to an inside surface of a shoe 290. The cupped heel portion of the orthotic insert has a concave upper bearing surface that extends above a most posterior cephalad portion of a calcaneous. The heat-malleable mid-foot portion of the orthotic insert is continuously coupled to the heel portion. The mid-foot portion has a medial longitudinal arch and a heat-deformable upper bearing surface. The cupped heel portion and the mid-foot portion cooperate to invert the subtalor joint of a foot to a position of slight inversion and to lock the midtarsal joint of the foot during ambulation to reduce pronation and provide stablilization.
Heat-[0046] malleable mid-foot piece 270 conforms to the contours of the mid-foot region of a wearer's foot. When heated, heat-malleable mid-foot piece 270 can be pressed into a shape that helps to maintain a subtalor joint of a user's foot 260 in an inverted position, and to lock the midtarsal joint during ambulation of the foot.
Heat-[0047] malleable mid-foot piece 270 of the orthotic insert has a heat-deformable upper bearing surface that is plastically deformed when the orthotic insert is heated above a glass transition temperature and compressed by user's foot 260 while the heat-malleable material of the orthotic insert is above the glass transition temperature.
[0048] Shoe 290 can be of various designs such as a sports shoe, a children's shoe, a work shoe, a dress shoe, a casual shoe, and a boot. For example, a traditional athletic shoe often has soft-sided uppers that are formed of cloth, vinyl, or other flexible materials that yield outwardly under pressure, thereby providing little inward buttressing around the insole. Pre-molded piece 280 and heat-malleable mid-foot piece 270 are readily adapted to various sizes and types of shoes. They are designed to protect and be in contact with the bottom of user's foot 260.
The perimeter surface of [0049] pre-molded piece 280 and heat-malleable mid-foot piece 270 are usually angled to match the inside of shoe 290 where the upper typically joins the sole of shoe 290.
FIG. 3 illustrates a perspective view of a foot, a shoe, and another embodiment of an orthotic shoe insert, the latter assembled with a heat-malleable mid-foot piece on top of a full-length pre-molded piece, in accordance with one embodiment of the present invention at [0050] 300. This exemplary orthotic shoe insert 300 comprises a pre-molded piece 380 that extends the full length of a wearer's foot 360. The orthotic shoe insert is positioned into a user's shoe 390. Pre-molded piece 380 is a full-length foot size with a heat-malleable piece 370 coupled to its mid-foot area. Pre-molded piece 380 and heat-malleable piece 370 are coupled to create a continuous upper bearing surface that contacts the entire bottom of a wearer's foot 360.
FIG. 4 illustrates a perspective view of an orthotic shoe insert with a pre-molded piece and heat-malleable mid-foot piece, in accordance with one embodiment of the present invention at [0051] 400. An exemplary pre-molded piece 480 of an orthotic insert 400 includes a cupped heel portion 450, having a concave upper bearing surface 452 and an upwardly concave shape for engaging the heel of a foot, and a relatively thin, substantially planar lower surface of a mid-foot portion 430, upon which a heat-malleable piece 470 is coupled. Heat-malleable piece 470 typically has a medial longitudinal arch support with a curvilinear upper bearing surface 432 for engaging an arch portion of the foot.
[0052] Cupped heel portion 450 extends above a posterior portion of a heel bone and is continuously coupled to mid-foot portion 430. Cupped heel portion 450 has a concave upper bearing surface that extends above a most posterior cephalad portion of a calcaneous. Frontal extremities of cupped heel portion 450 may be positioned somewhat more forwardly on the medial side than on the lateral side. Cupped heel portion 450 deforms to conform to the shape of the heel and to provide medial, posterior and lateral support to the calcaneus. A posterior surface of cupped heel portion 450 may engage the heel above the heel bone close to the Achilles tendon. A medial surface and a lateral surface of cupped heel portion 450 may engage the heel bone below the ankle malleolus. The upper edge of cupped heel portion 450 may extend along an arcuate path in a generally descending manner from the Achilles tendon to mid-foot portion 430.
[0053] Cupped heel portion 450 may act simultaneously on the calcaneus and subtalar of the foot. Cupped heel portion 450 may help to stabilize and control the motion of the foot, keeping the heel in its natural state and preventing it from excessively pronating or rolling inward during walking and running, thereby properly aligning the foot and providing better shock absorption and stress distribution.
[0054] Mid-foot portion 430 comprises a heat-malleable material. Mid-foot portion 430 of pre-molded piece 480 and heat-malleable piece 470 may extend from cupped heel portion 450 to an opposite end corresponding to the anterior ends of the metatarsal bones, and from the inner or medial portion to the outer or lateral side of the foot. Mid-foot portion 430 may comprise a heat-malleable material throughout. Alternatively, mid-foot portion 430 may comprise a polymeric lining above or below pre-molded piece 480. In another embodiment, the heat-malleable material is located interior to mid-foot portion 430.
[0055] Upper bearing surface 452 of cupped heel portion 450 and upper bearing surface 432 of heat-malleable piece 470 are continuously curvilinear, adapted to follow the contours of the plantar surface of the foot. The shape of heat-malleable piece may be generally shaped with a raised arch area to provide support for the arches of the foot without collapsing under body weight. Lower bearing surface 454 of cupped heel portion 450 and lower bearing surface 434 of mid-foot portion 430 may be shaped to substantially conform to an inside surface of a shoe.
[0056] Mid-foot portion 430 limits stretching of the plantar fascia and stabilizes the heel of the foot while walking or running. Cupped heel portion 450 and mid-foot portion 430 cooperate to provide a therapeutic characteristic for a podiatric condition, which may include plantar fasciitis or another medical condition or foot ailment such as cuboid syndrome, a neuroma, hammertoe, a bunion, a pronation condition, tendonitis, or a foot ailment. Other podiatric conditions may include fat pad atrophy, heel spurs, metatarsalgia, diabetic foot, hyperkeratosis, Morton's neuroma, plantar pain from arthritis or peak shock load, sore heels, sore knees, shin splints, Sever's disease, calcaneal apophysitis, bursitis, Achilles tendonitis, and elongated metatarsals.
[0057] Cupped heel portion 450 and mid-foot portion 430 of pre-molded piece 480 comprise a flexible material. Pre-moldable piece 480 is typically made of a flexible and moldable material such a neoprene rubber, a silicone rubber, an elastomer, a polymeric material, a urethane, polyethylene terephthalate, a viscoelastic material, a silicone gel, or any combination thereof.
Heat-[0058] malleable piece 470 in mid-foot portion 430 comprises a somewhat more rigid, heat-softenable or heat-malleable polymeric material such as polycaprolactone, polylactide, polyethylene terephthalate (PET), polyglycolide, copolymers of the aforementioned polymers, other thermoplastic polymers, or combinations thereof.
In an alternative embodiment of the orthotic insert, an optional pre-molded forefoot portion extends from the forward end of [0059] mid-foot portion 430 to the end of the forefoot portion corresponding to the distal ends of the phalanges, and from a medial side to a lateral side of the foot. When pre-molded forefoot portion is used, it usually has a relatively thin, substantially planar upper bearing surface. A forefoot portion is continuously coupled to mid-foot portion 430 and extends from the front of mid-foot portion 430 to a region corresponding to the distal end of the foot while comfortably encompassing the bottoms of the toes. The forefoot portion may reduce stress on the balls of the foot, and aid in distributing ambulatory stresses into the front portion of the foot.
A heat-malleable material may be included in at least a portion of the forefoot portion. The heat-malleable material may be a liner attached to the upper or lower surface of the optional forefoot portion, laminated within the forefoot portion or extending throughout the forefoot portion. [0060]
A heat-malleable material may be included in at least a portion of [0061] cupped heel portion 480. For example, a heat-malleable liner may be attached to the upper bearing surface of cupped heel portion 480. The heat-malleable material may be located in the interior of cupped heel portion 480, or attached to the lower surface of cupped heel portion 480.
[0062] Pre-molded piece 480 of orthotic insert 400 may be relatively thick in cupped heel portion 450 under and around the heel of the foot, and relatively thin and flexible near its upper and lateral edges. Orthotic insert 400 may be relatively thick at the arched regions of mid-foot portion 430, particularly in the region under the medial longitudinal arch of the foot, and relatively thin near the sides. The thickness is dependent on the dimensions of heat-malleable piece 470 and pre-molded piece 480. Alternatively, pre-molded piece 480 may be extended into a forefoot portion; the forefoot extension being relatively thin and generally flat or planar.
The size of the insert is selected to accommodate a particular shoe size or a range of shoe sizes. The dimensions of the insert and in particular, [0063] pre-molded piece 480, are determined to provide a proper fit for a range of shoe sizes and styles. Pre-molded piece 480 has a seamless surface with contours that conform to the foot to provide structural stability and foot support.
The lightweight material of [0064] pre-molded piece 480 made of compression-resistant, deformable material provides shock attenuation and support. The lower layer of orthotic insert 400 is made from a flexible material that can cushion and absorb the shock from heel strike on orthotic insert 400. Pre-molded piece 480 can be formed from a substantially flexible, resiliently compressible cushioning material having an upper bearing surface for engaging a plantar surface of a foot and a lower bearing surface for engaging a sole of a shoe. Pre-molded piece 480 can also employ a semi-rigid, injection moldable material. The durometer value of the flexible material may extend from a value less than 20 to a value in excess of 70.
The flexible material comprises a material such as neoprene rubber, silicone rubber, an elastomer, a polymeric material, a urethane, polyethylene terephthalate, a viscoelastic polymer, a silicone gel, or combinations thereof. The flexible and shock-absorbing polymeric material may be a lightweight and durable thermoplastic such as polyethylene or cross-linked ethylene vinyl acetate foam, cross-linked polyethylene, poly(ethylene-vinyl acetate), polyvinyl chloride, an acrylic, synthetic and natural latex rubbers, block polymer elastomers, thermoplastic elastomers, polystyrene, ethylene propylene rubbers, silicone elastomers, polystyrene, polyurea or polyurethane, a polyurethane foam, an elastomeric foam, a non-foam elastomer, and combinations thereof. These flexible materials may comprise a gripping characteristic that allows the orthotic shoe insert to firmly engage a heel and mid-foot. [0065] Pre-molded piece 480 may have a texture embossed on the upper bearing surface to improve the gripping characteristic.
Additional reinforcing support members may be built into [0066] pre-molded piece 480. For example, a rim region of harder material may surround the base of the cupped heel portion. Reinforcing support members may be built into the cupped heel portion of the insert to provide additional support of the calcaneous using, for example, semi-circular rods of high strength, resilient material extending around the back and sides of the heel, or extending upwards from the base of the cupped heel portion towards the ankle. Regions of soft, gel-like material may be incorporated into select regions of the insert, such as directly underneath the fat pad of the foot where heels may bruise and bone spurs may occur.
Heat-[0067] malleable piece 470, which is coupled to pre-molded piece 480, is customized by heating it to a temperature at which it can be deformed and fit to a user's foot. Heat-malleable piece 470 has sufficiently impressionable material that, when softened, the upper surface of the orthotic insert may be deformed with pressure of a person's foot, engaging and cradling the plantar surface of that foot. After cooling, the mid-foot portion 430 provides a customized curvilinear upper bearing surface to support the wearer's foot.
Heat-[0068] malleable piece 470 may comprise a polymeric lining formed from heat-malleable polymeric materials such as polycaprolatone, polylactide, polyethylene terephthalate (PET), polyglycolide, a thermoplastic polymer, copolymers of the aforementioned polymers, or any combination thereof. The heat-malleable piece 470 may be attached to pre-molded piece 480 by glue, adhesive, or some other coupling mechanism. In this and other embodiments of the invention that are described herein, a pharmaceutical compound such as a foot odor control compound or a cortical steroid may be included in the heat-malleable material. The heat-deformable upper bearing surface of 470 is plastically deformed when the orthotic insert is heated above a glass transition temperature and is compressed by a user's foot while the orthotic insert is above the glass transition temperature. The glass transition temperature of the heat-malleable material is typically between 45 and 75 degrees centigrade.
In another embodiment of the present invention, the heat-malleable material may be placed underneath a relatively thin layer of [0069] pre-molded piece 480 in mid-foot portion 430, allowing the weight of the foot upon the pre-molded piece and the heat-malleable piece underneath to deform the heated orthotic insert to the contours of the foot and to a shoe. Thus, depending on the insert design, heat-malleable material can be coupled to different locations on the underside of the pre-molded piece to accommodate different shapes, types and sizes of shoes and feet.
FIG. 5 illustrates a cross-sectional view of an orthotic shoe insert with a heat-malleable mid-foot piece and a pre-molded heel-cup piece, in accordance with one embodiment of the present invention at [0070] 500. A pre-molded piece 580 comprises a cupped heel portion 550 with a rear-foot lower bearing surface 554. A heat-malleable piece 570 comprises a mid-foot portion 530 with a mid-foot lower bearing surface 534. In this embodiment of the present invention, pre-molded piece 580 does not extend underneath the heat-malleable piece 570, as does the embodiment illustrated by FIG. 4.
Lower bearing surfaces [0071] 534 and 554 may be contoured to conform to an inside surface of a shoe and may have some texture, embossed patterns or other indenting or protruding features such as honeycomb structures, although their surfaces generally are flat and continuous with respect to one another.
The rear part of [0072] cupped heel portion 550 opens toward mid-foot portion 530, the heel cup being designed and dimensioned for adapting to the calcaneus. Cupped heel portion 550 may be continuously curved. An inner arcuate portion 556 and an outer arcuate portion 558 of cupped heel portion 550 above the calcaneous may be angled forwardly and upwardly and accorded a heel-cup angle alpha (α), the heel-cup angle alpha being measured by an arc sweeping from the base of the upwardly concave cupped heel portion 550 to the top of inner arcuate portion 556. Alternatively, heel-cup angle alpha may be measured by an angle corresponding to a line essentially parallel to lower bearing surface 554 of cupped heel portion 550 and a line essentially tangential to the top of outer arcuate portion 558, with a larger heel-cup angle corresponding to a fuller heel cup. The heel-cup angle of the currently preferred embodiment may be greater than 60 degrees, and preferably greater than 90 degrees.
A larger heel-cup angle provides more support and stability for the calcaneous, cooperating with [0073] mid-foot portion 530 to invert the subtalor joint of a foot to a position of slight inversion while walking or running. The medial, posterior, and lateral portions of the heel cup may hold the vertical axis of the calcaneus essentially coaxial with the axis of the leg. The longitudinal axis of cupped heel portion 550 and mid-foot portions 530 are oriented toward the fifth metatarsus of the foot so as to likewise orient the calcaneus.
[0074] Cupped heel portion 550 permits limited freedom of movement of the heel relative to the mid-foot portion when the insert is worn. The bottom region of the heel cup may be thicker to absorb the primary force of a heel strike. Reinforcement support members may optionally be embedded and secured into the heel cup to provide additional support for the calcaneous. Regions of softer, pliable material or detents may be formed in the bottom region of the heel cup to provide comfort and relief from heel spurs, for example, or atrophy of the fat pad.
Heat-[0075] malleable piece 570, which is coupled to pre-molded piece 580, is made of material that, when softened, may be deformed with pressure of a person's foot, engaging and conforming to the plantar surface of that foot. Optionally, heat-malleable piece 570 may be extended into the forefoot area, and heat malleable material may be added to the forefoot and rearfoot areas of pre-molded piece 580 to support the foot and to improve the fit of the insert into a particular shoe.
FIG. 6 shows an inside of an orthotic shoe insert from a perspective view, in accordance with one embodiment of the current invention at [0076] 600. Partial length orthotic insert 600 with a heat-malleable portion 670 and a pre-molded portion 680 may have upper or bottom surfaces that are either smooth or are embellished with various patterns and textures. The flexible material of pre-molded portion 680 that is textured can have an improved gripping characteristic to provide proximal, posterior and lateral support when engaged with the calcaneous of a foot. The texture may be particularly effective on the upper bearing surface of the heel cup of a pre-molded piece 680, which helps to effectively engage the heel and redistribute stresses. Texture surfaces may enhance contact with the foot or the sole of a shoe. Textured surfaces such as deep waffle or honeycomb patterns on the lower bearing surface of orthotic insert 600 may enhance its shock-absorbing qualities.
FIG. 7 is a flow diagram of a method of manufacturing an orthotic insert for a shoe, in accordance with one embodiment of the present invention at [0077] 700. The orthotic insert that results from the manufacturing process has a cupped heel portion with a concave upper bearing surface that extends above a most posterior cephalad portion of a calcaneous of a foot. The concave upper bearing surface of the cupped heel portion has a heel-cup angle of at least 60 degrees. The mid-foot portion, which has a heat-deformable upper bearing surface, is continuously coupled to the heel portion, the mid-foot portion having a medial longitudinal arch and a curvilinear upper bearing surface. When a forefoot portion is included, it has an upper bearing surface with a general outline around the toe or distal end of a foot.
[0078] Insert manufacturing method 700 begins by providing an orthotic insert mold as seen at block 710. The mold has a cavity for at least a cupped heel portion, the cupped heel portion having a concave upper bearing surface that extends above the heel bone of a user's foot. In some embodiments of the present invention, the mold includes a cavity for a mid-foot portion, the mid-foot portion continuously coupled to the heel portion and having a medial longitudinal arch. In another embodiment, the mold includes a cavity for a forefoot portion. One or more optional support members can be added to the moldable material to provide additional structure and reinforcement. For example, a rim region of harder material can be used to surround the base of the cupped heel portion. In another example, reinforcing support members are built into the cupped heel portion of the insert to provide additional support of the calcaneous, using semi-circular rods of high strength, resilient material extending around the back and sides of the heel, or upwards from the base of the cupped heel portion towards the ankle. In a third example, an optional pre-molded support member is inserted into the orthotic insert mold prior to the injection of a molding compound.
A moldable material is injected into the orthotic insert mold, as seen at [0079] block 720. The injection-molding compound may include a neoprene rubber, a silicone rubber, an elastomer, a polymeric material, a urethane, polyethylene terephthalate, a viscoelastic material, a silicone gel, or any combination thereof. The compound may be cured or treated to form the flexible material, as is known in the art. When a pre-molded support member is provided, the member is inserted into the insert mold prior to injecting the injection-molding compound.
The orthotic insert is released from the orthotic insert mold, as seen at [0080] block 730. At this point or later, an optional absorbing material may be attached to at least a portion of the upper bearing surface of the pre-molded part of the orthotic insert.
A heat-malleable material then is inserted into the orthotic insert, as seen at [0081] block 740. The heat-malleable material is inserted into at least the mid-foot portion of the orthotic insert to form a heat-deformable upper bearing surface. The heat-malleable mid-foot portion is coupled to the heel-cup portion with adhesive, glue or other attaching methods. Alternatively, the heat-malleable material can be attached to upper or lower surfaces of the pre-molded piece in one or more areas of the heel cup, mid-foot or rearfoot regions.
In one embodiment of the present invention, a thermochromatic indicator is inserted into the mid-foot portion of the orthotic insert. The thermochromatic indicator may be dispersed within the heat-malleable material, or attached to the heat-malleable material for indicating the temperature of the heat-malleable material. [0082]
The upper bearing surface of the cupped heel portion of the pre-molded piece and the heat-deformable upper bearing surface of the heat-malleable piece substantially conform to an undersurface of a foot. The heat-malleable piece is manufactured from a material that may be plastically deformed when the orthotic insert is heated above a glass transition temperature, which is typically between 45 and 75 degrees centigrade. Optionally, a pharmaceutical compound may added to the orthotic insert and an absorbing material may be attached to a portion of the upper bearing surface of the orthotic insert. [0083]
FIG. 8 is a flow diagram of a method of treating a podiatric condition, in accordance with one embodiment of the present invention at [0084] 800. Podiatric treatment method 800 may occur in an office of a foot specialist, at a user's home, or any convenient place where a heating unit may be employed. Podiatric treatment method 800 begins with providing a heat-malleable orthotic insert, as seen at block 810. The orthotic insert includes a cupped heel portion, the cupped heel portion having a concave upper bearing surface that extends above the most posterior cephalad portion of a calcaneous. The orthotic insert also includes a heat-malleable mid-foot portion continuously coupled to the heel portion, the mid-foot portion having a medial longitudinal arch and a heat-deformable upper bearing surface.
A foot specialist may tape or strap a foot of a patient into a neutral position, for example, with low-Dye strap or a high-Dye strap, as seen at [0085] block 820. The tape is applied to the foot to support the arch and relieve pressure on the plantar fascia ligament. Low-Dye and high-Dye taping or strapping, named after Dr. Ralph Dye, helps to realign foot bones, which can optimize ligament/muscle function and improve foot biomechanics. Strapping is used to configure and maintain the foot in a preferred position when re-forming the heat-malleable material in the insert.
The foot specialist or user of the orthotic insert heats the heat-malleable orthotic insert with a heating apparatus to a temperature above a glass transition temperature of the mid-foot portion, as seen at [0086] block 830. Depending on the heat-malleable material selected, various heating apparatuses may be used such as a microwave oven, a convective oven, a hot-air gun, a heating pad, a pan of heated water, or any suitable heat-malleable orthotic insert heating unit.
The strapped foot is pressed into the orthotic insert when the mid-foot portion is above the glass transition temperature, as seen at [0087] block 840. At that temperature, the heat-deformable upper bearing surface of the mid-foot portion may be plastically deformed into a shape corresponding substantially to the underside of the strapped foot. The strapped foot and the heated orthotic insert may be pressed into the shoe when the mid-foot portion is above the glass transition temperature to plastically deform the lower bearing surface of the mid-foot portion into a shape corresponding substantially to an upper bearing surface of the shoe.
Heat sensitive polymers that change color at various temperatures may be incorporated into the orthotic insert. For example, a thermochromatic indicator may change from yellow to red at 180° Fahrenheit, the temperature at which a person would suffer a burn, or at other predetermined temperatures. A preferred embodiment uses a polymer that is blue at a cold temperature, changing to red at a hot temperature. Alternative embodiments may use a label consisting of heat-sensitive indicator sealed under a transparent window that changes, for example, from light gray to black as one or more rated temperatures are reached above 38° C. (100° F.). [0088]
Although the heat-malleable foot insert may be fit to a foot outside of a shoe, more often the strapped foot is pressed into an orthotic insert that has been inserted into an article of footwear, as seen at [0089] block 850. The heat-malleable material of the orthotic insert provides a custom fit to both the user's foot and a particular shoe in which the foot and insert are placed.
The foot is pressed and held into a neutral position by the low-Dye or other similar foot taping or strapping techniques until the heat-malleable orthotic insert is cooled to a temperature below the glass transition temperature, such as an ambient temperature, as seen at [0090] block 860. The heat-malleable material hardens and retains a shape that corresponds substantially to the underside of the foot and to an inner surface of the article of footwear. The result is an orthotic insert that is fit to both the patient and the shoe with which the insert will be worn. The foot may be removed and unstrapped. When the user wears the shoe with the newly shaped orthotic insert, the customized insert will help to keep the user's foot in a neutral position during ambulation and to provide therapeutic and preventive characteristics.
While the embodiments of the invention disclosed herein are presently considered to be preferred, various changes and modifications can be made without departing from the spirit and scope of the invention. The scope of the invention is indicated in the appended claims, and all changes that come within the meaning and range of equivalents are intended to be embraced therein. [0091]

Claims

What is claimed as invention is:

1. An orthotic insert for an article of footwear, comprising:

a cupped heel portion, the cupped heel portion having a concave upper bearing surface that extends above a most posterior cephalad portion of a calcaneous; and

a heat-malleable mid-foot portion continuously coupled to the heel portion, the mid-foot portion having a medial longitudinal arch and a heat-deformable upper bearing surface.

2. The orthotic insert of claim 1 wherein the cupped heel portion and the mid-foot portion cooperate to invert a subtalor joint of a foot to a position of inversion and to lock a midtarsal joint of the foot during ambulation to reduce pronation and provide stabilization.

3. The orthotic insert of claim 1 wherein the concave upper bearing surface of the cupped heel portion comprises a heel-cup angle of at least 60 degrees.

4. The orthotic insert of claim 1 wherein the mid-foot portion extends from the cupped heel portion to an opposite end corresponding to an anterior end of a metatarsal bone.

5. The orthotic insert of claim 1 wherein the cupped heel portion and the mid-foot portion comprise a flexible material.

6. The orthotic insert of claim 5 wherein the flexible material is selected from the group consisting of a neoprene rubber, a silicone rubber, an elastomer, a polymeric material, a urethane, polyethylene terephthalate, a viscoelastic material, a silicone gel, and combinations thereof.

7. The orthotic insert of claim 1 wherein the heat-malleable mid-foot portion comprises a heat-malleable material.

8. The orthotic insert of claim 7 wherein the heat-malleable material comprises a material selected from the group consisting of polycaprolactone, polylactide, polyethylene terephthalate, polyglycolide, and a thermoplastic polymer.

9. The orthotic insert of claim 1 wherein the heat-deformable upper bearing surface of the mid-foot portion is plastically deformed when the orthotic insert is heated above a glass transition temperature and compressed by a foot while the orthotic insert is above the glass transition temperature.

10. The orthotic insert of claim 9 wherein the glass transition temperature is between 45 and 75 degrees centigrade.

11. The orthotic insert of claim 1 wherein the cupped heel portion and the mid-foot portion cooperate to provide a therapeutic characteristic for a podiatric condition.

12. The orthotic insert of claim 11 wherein the podiatric condition is selected from the group consisting of a heel spur, arch pain, metatarsalgia, a bunion, hammertoe, arthritis, a neuroma, diabetes foot, plantar fasciitis, cuboid syndrome, tendonitis, a stress fracture, shin splints, a pronation condition, and a foot ailment.

13. The orthotic insert of claim 1 further comprising:

a lower bearing surface substantially conforming to an inside surface of the article of footwear.

14. The orthotic insert of claim 1 further comprising:

a heat-malleable material in at least a portion of the cupped heel portion.

15. The orthotic insert of claim 1 further comprising:

a forefoot portion continuously coupled to the mid-foot portion, the forefoot portion extending from the mid-foot portion to a region corresponding to a distal end of a foot and from a medial side to a lateral side of the foot.

16. The orthotic insert of claim 15 further comprising:

a heat-malleable material in at least a portion of the forefoot portion.

17. The orthotic insert of claim 1 further comprising:

a thermochromatic indicator incorporated into the mid-foot portion of the orthotic insert.

18. A method of manufacturing an orthotic insert for an article of footwear, comprising:

providing an orthotic insert mold with a cavity for a cupped heel portion, the cupped heel portion having a concave upper bearing surface that extends above a most posterior cephalad portion of a calcaneous; and a cavity for a heat-malleable mid-foot portion continuously coupled to the heel portion, the mid-foot portion having a medial longitudinal arch;

injecting an injection-molding compound into the orthotic insert mold;

releasing the orthotic insert from the orthotic insert mold; and

inserting a heat-malleable material into at least the mid-foot portion of the orthotic insert.

19. The method of claim 18 wherein the injection-molding compound is selected from the group consisting of a neoprene rubber, a silicone rubber, an elastomer, a polymeric material, a urethane, polyethylene terephthalate, a viscoelastic material, a silicone gel, and combinations thereof.

21. The method of claim 18 further comprising:

inserting a thermochromatic indicator into the mid-foot portion of the orthotic insert.

22. A method of treating a podiatric condition, comprising:

providing a heat-malleable orthotic insert, the heat-malleable orthotic insert including a cupped heel portion, the cupped heel portion having a concave upper bearing surface that extends above a most posterior cephalad portion of a calcaneous; and a heat-malleable mid-foot portion continuously coupled to the heel portion, the mid-foot portion having a medial longitudinal arch and a heat-deformable upper bearing surface;

strapping a foot into a neutral position;

heating the heat-malleable orthotic insert with a heating apparatus to a temperature above a glass transition temperature of the mid-foot portion;

pressing the strapped foot into the heat-malleable orthotic insert when the mid-foot portion is above the glass transition temperature to plastically deform the heat-deformable upper bearing surface of the mid-foot portion into a shape corresponding substantially to the underside of the strapped foot; and

cooling the heat-malleable orthotic insert to a temperature below the glass transition temperature.

23. The method of claim 21 wherein the heating apparatus is selected from the group consisting of a microwave oven, a convective oven, a hot-air gun, a heating pad, a pan of heated water, and a heat-malleable orthotic insert heating unit.

24. The method of claim 21 further comprising:

pressing the strapped foot and the heated orthotic insert into an article of footwear when the mid-foot portion is above the glass transition temperature to plastically deform a lower bearing surface of the mid-foot portion into a shape corresponding substantially to an upper bearing surface of the article of footwear.