Purpose of the invention
[0001] This invention is aimed at providing new footwear for children that helps to prevent
the appearance of certain pathologies. Specifically, it develops a system to correct
foot movement in children with a slight tendency to develop pes valgus, without changing
the gait of children without this pathology. However, it also aims to provide this
new footwear with suitable characteristics, according to the functional needs and
comfort of children when walking.
History of the invention
[0002] As it grows, the foot goes through a series of stages of development, that need to
be recognised in order to identify what is normal and what is pathological at any
given time. The footwear worn by children at each of these stages of development can
have a critical effect on its development. In general, footwear should protect against
aggression from the environment in which a child develops, safeguarding their physical
and motor development. At the same time, it should provide thermal and mechanical
comfort, while ensuring that it performs its function without causing lesions or damage,
promoting normal growth and development. Footwear should also allow the child to feel
the ground, so as to promote sensory stimulation, proper development of the nervous
system and improved balance.
[0003] At birth and around the age of one year, the foot is mostly comprised of cartilage,
and vulnerable to any external aggression. As a result, when the child starts to take
his or her first steps, it is very important to prevent excessive weight, and to help
the foot by using suitable footwear that controls the position of the heel, without
restricting the toes too much.
[0004] The most critical stage in a child's musculoskeletal and neurological development
is when he/she starts to walk, at between 10 and 18 months. This is the period when
they attempt to achieve verticality, when almost anything is possible when it comes
to supporting the body, and what may be nothing more than a transition towards "normality"
should not necessarily be viewed as pathological. Some children fall frequently, others
stand with their foot pointing inwards, others point their feet outwards, etc. Furthermore,
at this stage the physiological transition from Genu Varum ("bowleggedness") to Genu
Valgum ("x-shaped legs") takes place, and vice versa, until the muscles of the feet
strengthen. This also has repercussions on the means of supporting the feet. There
is also an increase in the plantar fat pad of the arch or inner arch, which can give
the appearance of a false flat foot. In light of all of the above, it is very difficult
to talk about flat footedness or Genu Valgum, which tend to be false problems, often
exacerbated by maternal worry and mothers being kept more or less uninformed by one
or more doctors. From one to 4 years the child gradually improves his/her balance
and acquires experience on how to stay standing and walk. From this moment, the muscles
begin to exercise themselves, gradually hardening the ligaments and the bones until
the arch is practically formed, and the foot adopts the characteristic form of an
adult foot. Until the age of 7, the child's gait matures until it has acquired the
adult pattern, and finally, from 7 to 14 years, the child increases his/her physical
activity considerably.
[0005] However, many children still present with weak ligaments at 4 years. As a result,
these children do not have a fully formed arch and occasionally the talotibial joint
is not in line with the vertical axis. In this case, we say that the child is presenting
with pes valgus because of weak ligaments that do not allow the foot's structure to
be tightened in order to line it up, making its basic function of support to be fulfilled.
[0006] Depending on the gravity of the situation, various solutions are applied, from exercises
aimed at strengthening the muscles, to walking on tiptoe, to the use of suitable orthopaedic
insoles, to surgical treatment (only in approximately 5% of cases). For example, we
know of document
WO 90/05504, which describes a method of manufacturing a plaster of Paris insole to correct pes
valgus by controlling the front, middle and back of the foot. Document
WO 00/15163 also describes a device designed to correct pes valgus, consisting of a sort of brace
that corrects the position of the big toe.
[0007] This invention, however, is not designed for use with the user's footwear. Instead,
it uses specially adapted footwear for the correction of pes valgus. The internal
system cannot move about within the footwear, thereby preventing unwanted internal
postures and deformities that could have a negative effect on the foot. It remains
perfectly in place and adapted to the shape of the foot, without squashing it. It
also adapts to the movements of the foot, providing a stable gait with no need to
exert unnecessary pressure. Another of the fundamental characteristics of the invention
consists of adapting the last of the shoe, ensuring that it fits the shape of the
foot perfectly, preventing looseness in the heel area that could lead to instability,
while nevertheless allowing the toes to move freely.
Description of the invention
[0008] The footwear we suggest to improve the stability of pes valgus and healthy feet in
children consists of a system to correct the movement of the feet in children with
a slight tendency to walk with their heel facing outwards, also known as pes valgus,
ensuring the characteristics and functional needs to provide comfort for children
when walking. It is important to stress that the footwear is designed to have an effect
on subjects with only a slight tendency towards pes valgus, but who clearly present
with the pathology. It can be used in healthy subjects, without having any negative
effect on them. However, if used in subjects with marked pes valgus, while it will
improve their gait, there is no proof that it will cure the pathology.
[0009] The development of the footwear was based on a series of tests and analyses that
are presented below.
[0010] Firstly, in order to develop the project, it was necessary to characterise the gait
pattern, i.e. we needed to determine the scientific basis required to establish the
needs of the infant population in terms of footwear to correct the gait pattern in
children with a tendency to develop pes valgus in healthy feet. To this end, the gait
pattern of 35 children aged between 2.5 and 11 years was analysed. The criterion used
to choose the subjects was to cover the age range of the different stages of maturity
of gait (1-4, 4-7 and 7-11 years), and to use both healthy subjects and subjects with
pes valgus.
[0011] Different types of testing were carried out in order to characterise the gait pattern,
based on analyses of foot pressure when bare or wearing shoes. Firstly, in order to
obtain the distribution of plantar pressure while walking with shoes on, instrumented
insoles were used. A shoe that would interfere as little as possible with the natural
gait pattern of a child was chosen. Every child walked three times straight through
a special area, and the plantar pressure between the foot and footwear was measured
to find the characteristic plantar register for each child. Secondly, in order to
complete the information characterising the distribution pattern of plantar pressure,
records were obtained from the same sample of children walking barefoot, using a pressure
platform. Two types of assessment were carried out: firstly, as with the test using
shoes, the children were asked to walk straight through an area designed for the purpose,
and the plantar pressure between foot and floor was measured, with three repetitions
per child. The children were then asked to stand with their feet still on a platform,
to register the pressure in the standing position.
[0012] Secondly, after characterising the gait pattern, the morphology of the childrens'
feet was analysed, to determine the development of the foot at ages between 2.5 and
11 years of age. These data were subsequently used to define the last and insoles
of the children. The basis for this was an analysis of records from the morphological
database of Instituto de Biomecánica de Valencia (Valencia Institute of Biomechanics),
which we completed by adding 3D digitisation of the foot of the children, using a
digital scanner. The tests in this phase were carried out at the same time as the
gait pattern tests, using the same children.
[0013] Thirdly, with the data collected from the characterisation of the gait pattern and
the morphological analysis, the process of developing pes valgus was characterised,
as was the influence that footwear has on this. This phase included two stages:
a) Clinical diagnosis. A clinical diagnosis was carried out to determine whether or
not the children involved in the study presented with pes valgus, supported by the
visual analysis carried out during the testing and the analysis of the plantar pressure
records for bare feet. As a result of this analysis, the children were classified
into three types in relation to pes valgus: healthy, valgus and undefined. The subjects
were then divided into three stages:
■ Stage 1: 2 to 5 years. Practically all of the children presented with one pes valgus,
due to weak ligaments caused by the immaturity of the structures. At this stage it
is impossible to tell whether a child is going to develop the pathology or not, except
for some very extreme cases, which places them outside the scope of the project, in
any case.
■ Stage 2: 6 to 7 years. This age range corresponds to the end of the stage of maturity
of gait, in which its pattern starts to be defined. There was a balance between healthy
children and those with pes valgus. This is where the pathology might start to develop
or the structures start to harden and the muscles to strengthen. This age range is
therefore of particular interest when correcting the gait pattern associated with
this pathology.
■ Stage 3: 7 to 12 years. The majority of the children presented with the pathology
or were healthy, with the latter being the largest group. At this stage, it is already
clear whether or not a child has developed the pathology. This stage is when a child
starts to increase their activity. It would therefore be interesting to use footwear
to correct the gait pattern of children with pathological tendencies.
The results obtained from the clinical diagnosis were as follows:
Child |
Age |
Weight |
Foot size |
Pathology |
31 |
2,5 |
18 |
25 |
valgus-healthy |
2 |
2,5 |
|
24 |
valgus-healthy |
22 |
2,5 |
12 |
23 |
valgus |
19 |
2,5 |
18 |
26 |
valgus |
8 |
3,0 |
19 |
27 |
valgus-healthy |
20 |
4,0 |
25,4 |
28 |
valgus |
16 |
4,0 |
16 |
26 |
healthy |
4 |
4,0 |
21 |
|
valgus-healthy |
6 |
4,5 |
17 |
27 |
valgus-healthy |
28 |
5,0 |
24 |
31 |
valgus |
33 |
5,0 |
25 |
31 |
valgus |
10 |
5,0 |
19 |
30 |
valgus |
29 |
5,0 |
19 |
29 |
valgus-healthy |
17 |
5.0 |
16 |
28 |
valgus |
34 |
5,0 |
19 |
28 |
valgus |
24 |
6,0 |
22 |
31-32 |
healthy |
30 |
6,0 |
33,5 |
34 |
valgus |
13 |
6,0 |
31 |
33 |
healthy |
5 |
6,0 |
21 |
30 |
valgus-healthy |
25 |
6,0 |
18 |
29 |
valgus |
32 |
6,5 |
25 |
32 |
healthy |
18 |
6,5 |
2 |
31 |
valgus |
14 |
7,0 |
42 |
35 |
valgus |
7 |
7,0 |
39 |
34 |
healthy |
15 |
8,0 |
35 |
34 |
healthy |
1 |
8.0 |
30 |
33 |
valgus |
26 |
8.0 |
30 |
33 |
valgus |
21 |
8,0 |
|
32 |
valgus-healthy |
12 |
9,0 |
34 |
34 |
healthy |
23 |
9,0 |
24 |
32 |
healthy |
11 |
10 |
38 |
38 |
healthy |
9 |
10 |
30 |
34 |
healthy |
35 |
11 |
40 |
39 |
healthy |
3 |
11 |
43 |
39 |
valgus |
27 |
11 |
40 |
36 |
healthy |
We concluded the following from the analysis:
- From 2.5 to 5 years of age, the majority of children presented with pes valgus.
- From 6 to 7 years of age, approximately half of the children presented with pes valgus.
- From 8 years of age, only some of the children developed the pathology.
We can therefore deduce that the critical stage for preventing pes valgus is between
5 and 7 years of age, when the muscles and structures are still strengthening. It
is during this stage that efforts to correct the standard gait of children with pathological
tendencies should focus.
b) Biomechanical analysis. Secondly, the data obtained from the tests using footwear
were analysed from a biomechanical viewpoint. After dividing the data into the three
stages and assessing the results, we came to the following conclusions: In Stage 1,
at 2.5 to 5 years, it was almost impossible, from a biomechanical viewpoint, to distinguish
between healthy children and those with pes valgus, based on the data obtained from
tests using footwear. However, at Stage 2, between the ages of 6 and 11 years, clear
differences were seen between healthy children and those with pes valgus. These differences
are apparent from a comparison between the average maximum pressure produced when
walking and the standard distribution of plantar pressure. There are different maximum
values in the group of valgus children for the forefoot and the hindfoot. In the hindfoot,
there were significant differences in distribution and, above all, in the magnitude
of the pressure registered, with valgus children showing lower pressure, also centred
in the middle of the footstep. In the forefoot, there were differences in the distribution
of pressure, which was more concentrated and displaced to the lateral area of the
footstep in children characterised as valgus.
There were also significant differences when comparing the gait pattern in healthy
and valgus children from 6 to 11 years. At the moment of contact with the floor, valgus
children were seen to make contact with greater intensity. As full support is produced,
the transfer of pressures to the forefoot takes place without developing the mechanism
that raises the plantar; therefore the forefoot is supported practically without passing
through the area between the forefoot and hindfoot. Finally, during the impulsion
phase, children with pes valgus tend to compensate the rolling of the foot towards
the medial area, by pushing harder on the lateral side of the forefoot. In general,
this behaviour is justified by a weakness of the structures in children with pes valgus,
which makes the foot much less efficient in completing its functions of support and
propulsion, with the resulting variation in gait pattern.
[0014] All of the information gathered from the tests described above were used to develop
the design criteria, taking into account not only the general criteria of comfort
and health, but also the fact that children with slight tendencies to develop pes
valgus require footwear that is capable of correcting the gait pattern, in order to
prevent the development of pes valgus. Footwear needs to support the correct development
of the gait pattern without interfering in a negative manner.
[0015] The geometric shape of the surface of footwear that comes into contact with the sole
of the child's foot is therefore defined, in order to correct the gait pattern. A
geometric shape was formed for the sole, footwear and insole, in the form of a channel
aimed at guiding the child's footstep, facilitating the correct distribution of dynamic
pressures, but not impacting negatively on its development. This geometric shape counteracts
the typical rolling of the foot with pes valgus onto the inside of the heel, guiding
it so as to achieve uniform support for the heel area, as seen in healthy children.
The shape is also designed so as not to interfere with the development of the gait
pattern in healthy children, since they develop a different footfall that is already
in line with the geometrically established pathway, therefore not affecting them.
Description of the drawings
[0016] To complete the description provided herein, with a view to ensuring better comprehension
of the characteristics of the invention. According to a preferential example of the
practical completion of the design, the following set of drawings accompanies this
description and forms an integral part hereof. They give an illustrative but not exhaustive
representation of the invention. Figure 1 shows a ground view of the footwear, representing
the three section axes A-A', B-B', C-C', serving as a basis for figures 2, 3 and 4.
Figure 2 shows a transversal section of the footwear from section axis C-C'.
Figure 3 shows a transversal section of the footwear from section axis B-B'.
Figure 4 shows a transversal section of the footwear from section axis A-A'.
Figure 5 shows the placement of the cup in relation to the insole, on which the last
is placed during the manufacturing process.
Figure 6 shows the placement of the cup in relation to the insole cardboard insole
and the sole.
Preferential completion of the invention
[0017] The proposed invention is based on achieving the shape of the footwear from the design
for the sole (3) and the footbed (6), with a geometric design in the upper part that
houses an insole (4) with the shape of the base. The sole (3) and the footbed (6)
are high density, while the insole (4) is low density, in order to permit the geometric
effect.
[0018] This is a new footwear design, based on a combination of geometric shape and materials.
A cup (1) is created in the heel area, designed to redirect the foot when pressure
is applied, inducing correct posture. This cup (1) consists of a hard part in the
form of a channel, integrated in the footwear between the footbed (6) and the insole
(4) on the back part of the sole (3). An insole (4) is placed over the cup (1). The
insole is removable, and made of material that is sufficiently mouldable to allow
the placement of the cup (1) to have the desired effect. The insole (4) has an upper
geometric shape that houses the foot anatomically and a lower shape that fits into
the cup (1). Thus, if we remove the insole (4) from the footwear, the cup (1) it is
resting on can be seen.
[0019] The last (5) needs to adjust properly to the shape of the foot. It was specially
designed to take into account the anthropometric shape of an average foot. Any looseness
in the heel area could cause increased instability. The cleavage line between the
instep and the heel is designed to close the footwear and adjust the last (5), similar
to the cleavage line that follows the tip of the metatarsals. Therefore the design
must be adhered to in these areas, to ensure proper adjustment. There must however
be room in the toe area, to allow them to move. This permits slight alterations to
the last (5) proposed, according, for example, to aesthetic considerations, provided
that such alterations do not affect the system.
[0020] The footbed (6) is composed of two parts, the cardboard footbed (7), used during
the construction of the footwear serves as a base for the insole (4), with a flat
and flexible shape to adapt to the last (5) and the cup (1). There is also a cup (1),
situated at the rear of the heel of the insole (4), shaped into a rigid material to
channel the footstep.
[0021] The sole (3) needs to fit the basic needs of the user and the specific requirements
of the system's innovative design. Thus, the material of the floor should be slightly
abrasive, principally in the heel area, with a view to ensuring that its shape does
not change with continuous use. The sole (3) should also facilitate the path of the
child's centre of mass along the track of the sole defined from studies of healthy
children, so that it stabilises the child's footstep. To achieve this, we either create
a double density sole in which the central track has a lower density than the rest
of the sole, or the thickness of that area is reduced to facilitate distortion, thus
stabilising the footstep.
[0022] The shape of the cut should generally adhere to the shape of the last (5). The height
of the cut should be at least 46 mm from the base of the insole (4) to the leg at
the lowest part of the cut.
1. This footwear corrects foot movement in children with a slight tendency to develop
pes valgus, without changing the gait of children without this pathology, using a
last (5) that can be adjusted to the shape of the foot, so that the cleavage line
between the instep and the heel and the cleavage line that follows the line of the
tips of the metatarsals are adjusted by the last (5), closing the shoe, and leaving
room in the toe area for them to move, designed to include a sole (3) made from unobtrusive material, principally in the area of the
heel, aimed at preserving the geometric shape with continuous use. The shoe also has
a high density footbed (6) comprising a cardboard footbed (7) and a cup (1), aimed
at guiding the footsteps, and a removable insole (4) made of a mouldable low density
material, ensuring that the shoe counteracts the typical rolling of pes valgus in
the inside of the heel.
2. The footwear corrects foot movement in children with a slight tendency to develop
pes valgus, without changing the gait of children without this pathology, according
to claim 1, designed because the cup (1) consists of a hard part in the form of a channel, integrated in the back
of the shoe's sole (3).
3. The footwear corrects foot movement in children with a slight tendency to develop
pes valgus, without changing the gait of children without this pathology, according
to claim 1, designed because the removable insole (4) has a flat upper shape that is anatomically designed to
house the foot, and a lower shape that fits into the cup (1).
4. The footwear corrects foot movement in children with a slight tendency to develop
pes valgus, without changing the gait of children without this pathology, according
to claim 1, designed because the insole (3) has a central track (2) of a lower density than the rest of the sole,
facilitating the path of the child's centre of mass.
5. The footwear corrects foot movement in children with a slight tendency to develop
pes valgus, without changing the gait of children without this pathology, according
to claim 4, designed because the central track (2) is formed by creating a double density sole (3).
6. The footwear corrects foot movement in children with a slight tendency to develop
pes valgus, without changing the gait of children without this pathology, according
to claim 4, designed because the central track (2) is formed by reducing the thickness in relation to the sole
(3).
7. The footwear corrects foot movement in children with a slight tendency to develop
pes valgus, without changing the gait of children without this pathology, according
to claim 1, designed because the geometrically flat cardboard footbed (7) is flexible, allowing it to adapt to
the last (5) and the cup (1), and is used when building the shoe, to serve as a base
for the insole (4).
8. The footwear corrects foot movement in children with a slight tendency to develop
pes valgus, without changing the gait of children without this pathology, according
to previous claims, designed because the geometry of the shoe's cut is moulded to the shape of the last (5) so that the
height of the cut needs to be at least 46 mm from the base of the insole (4) to the
leg at the lowest part of the cut.