U.S. patent application number 10/409539 was filed with the patent office on 2004-10-07 for heat malleable orthotic shoe insert.
Invention is credited to Campbell, Todd D., Davis, Russell C., Guthrie, William Y..
Application Number | 20040194348 10/409539 |
Document ID | / |
Family ID | 33097843 |
Filed Date | 2004-10-07 |
United States Patent
Application |
20040194348 |
Kind Code |
A1 |
Campbell, Todd D. ; et
al. |
October 7, 2004 |
Heat malleable orthotic shoe insert
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.
Inventors: |
Campbell, Todd D.;
(Petaluma, CA) ; Davis, Russell C.; (Greenbrae,
CA) ; Guthrie, William Y.; (Fairfax, CA) |
Correspondence
Address: |
JOHNSON & STAINBROOK, LLP
3558 ROUND BARN BLVD., SUITE 203
SANTA ROSA
CA
95403
US
|
Family ID: |
33097843 |
Appl. No.: |
10/409539 |
Filed: |
April 7, 2003 |
Current U.S.
Class: |
36/93 |
Current CPC
Class: |
A43B 17/16 20130101;
A43B 7/28 20130101; A43B 7/142 20130101; A43B 17/023 20130101 |
Class at
Publication: |
036/093 |
International
Class: |
A43B 007/14 |
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.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not applicable.
REFERENCE TO A MICROFICHE APPENDIX
[0003] Not applicable.
TECHNICAL FIELD
[0004] 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
[0005] 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.
[0006] 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.
[0007] 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.
[0008] 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.
[0009] 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.
[0010] 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.
[0011] 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.
[0012] 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.
[0013] 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
[0014] 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.
[0015] 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
[0016] 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.
[0017] 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:
[0018] FIG. 1 illustrates a side view and a top view of a human
foot;
[0019] 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;
[0020] 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;
[0021] 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;
[0022] 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;
[0023] FIG. 6 illustrates an inside of an orthotic shoe insert from
a perspective view, in accordance with one embodiment of the
current invention; and
[0024] 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
[0025] FIG. 8 is a flow diagram of a method of treating a podiatric
condition, in accordance with one embodiment of the current
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0026] 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.
[0027] 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.
[0028] 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.
[0029] 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.
[0030] 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.
[0031] 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.
[0032] 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.
[0033] 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.
[0034] FIG. 1 illustrates a side view and a top view of a human
foot at 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.
[0035] The mid-foot includes five 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.
[0036] The mid-foot also includes five of seven tarsal bones:
navicular, cuboid, and cuneiform bones. The distal row contains
three 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.
[0037] A 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.
[0038] 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.
[0039] 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.
[0040] 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
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.
[0041] 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.
[0042] 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.
[0043] 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.
[0044] 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.
[0045] 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 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.
[0046] Heat-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.
[0047] Heat-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.
[0049] The perimeter surface of 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.
[0050] 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 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.
[0051] 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 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.
[0058] Heat-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.
[0059] In an alternative embodiment of the orthotic insert, an
optional pre-molded forefoot portion extends from the forward end
of 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.
[0060] 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.
[0061] A heat-malleable material may be included in at least a
portion of 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.
[0063] 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, 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.
[0064] The lightweight material of 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.
[0065] 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. Pre-molded piece 480 may have a texture embossed on the
upper bearing surface to improve the gripping characteristic.
[0066] Additional reinforcing support members may be built into
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.
[0067] Heat-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.
[0068] Heat-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.
[0069] In another embodiment of the present invention, the
heat-malleable material may be placed underneath a relatively thin
layer of 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.
[0070] 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 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.
[0071] Lower bearing surfaces 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.
[0072] The rear part of 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 (.alpha.), 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.
[0073] A larger heel-cup angle provides more support and stability
for the calcaneous, cooperating with 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.
[0075] Heat-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.
[0076] FIG. 6 shows an inside of an orthotic shoe insert from a
perspective view, in accordance with one embodiment of the current
invention at 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.
[0077] 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 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.
[0079] A moldable material is injected into the orthotic insert
mold, as seen at 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.
[0080] The orthotic insert is released from the orthotic insert
mold, as seen at 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.
[0081] A heat-malleable material then is inserted into the orthotic
insert, as seen at 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.
[0082] 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.
[0083] 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.
[0084] FIG. 8 is a flow diagram of a method of treating a podiatric
condition, in accordance with one embodiment of the present
invention at 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.
[0085] 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 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.
[0086] 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 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.
[0087] The strapped foot is pressed into the orthotic insert when
the mid-foot portion is above the glass transition temperature, as
seen at 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.
[0088] 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.degree. 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.degree. C. (100.degree. F.).
[0089] 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 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.
[0090] 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 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.
[0091] 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.
* * * * *