FOOT ORTHOSIS APPARATUS

The present invention is directed towards an apparatus for enhancing proprioception in the foot of a subject.

Proprioception is a sense that informs the human body about the stability of individual joints and the body as a whole. Elderly people lose sufficient sense of proprioception which leads to loss of balance, stumbling, falls and accidents. Similar symptoms can be observed in the long-term ill and immobile. By increasing the proprioception of a subject, it has been shown that the number of falls experienced by the subject can be significantly reduced.

A key source of information for the body's proprioceptive sense is the plantar surface of the foot. The plantar surface is the surface of the foot that faces downwards when a subject is standing with both feet flat on the floor. The body determines the position of the foot and the general orientation of the lower limbs based, in part, upon information received from the plantar surfaces of the feet. In the elderly or infirm, the ability of the body to properly process this information and maintain a proper orientation of the body is reduced.

As a result, there is a need to provide a means of enhancing the proprioception in subjects, in order to try and prevent trips and falls.

Pronation is the flattening out of the arch of the foot when the foot strikes the ground. Normally, the foot will pronate in order to absorb shock when the heel hits the ground, and to assist in balance during mid-stance. During pronation the ankle will tip towards the medial side.

Excessive pronation can be problematic because the shifting causes increased stress on the medial side of the foot. Excessive pronation pulls on

the stabilising muscles in the lower leg and often causes the knee to shift to the inside. This may cause the body to overcompensate and shift the ankle towards the lateral side causing the ankle to roll over. This can result in a stumble or a fall, possibly with resultant injuries to the subject.

It is also desirable to provide a means for preventing excessive pronation in a subject.

US 6, 237, 256 discloses a balance-enhancing insert for footwear. The document is concerned with treating the loss of cutaneous sensation in the sole of the feet, in particular as a result of old age. The document describes a shoe sole that stimulates a response in the perimeter of the subject's foot, as a shift in weight and balance occurs. This is achieved using ridges or protrusions in the sole of the shoe in order to stimulate the feeling in the foot of the subject. This device features ridges or protrusions only around the perimeter of the sole. The protrusions feature no differential of height, nor do they target specific areas of the foot. This leads to the problem that, should the insert be worn often, the brain will adapt to the signals sent from the stimulated nerves in the foot and will no longer respond to the signals, so the proprioception of the subject will no longer be enhanced, thus over long periods of time, balance will not be improved.

US 2497937 discloses a non slip insole base. The insoles comprises a moulded pattern on the bottom, shoe contacting, surface. This pattern simply stops the insole from sliding about within the shoe of a wearer, and provides not further benefits than an insole of conventional design. In particular, the insole comprises nothing to specifically contact and interact with the foot of the user.

US 6237256 comprises a balance-enhanced insert for footwear having means for stimulating the plantar surface of the foot of a user. The means for stimulating the plantar surface of the foot only feature around the perimeter of

the insert. Although this may help proprioception, it may not be sufficient enough to treat people with severe proprioception difficulties.

US 4694831 discloses a massage footwear having protrusions thereon. The protrusions on the insert are designed to provide a massaging action to a user when they are walking. The protrusions are not placed so as to increase proprioception.

US 5704137 provides a shoe having a hydrodynamic pad. The pad uses an inner bladder to create a protrusion on the outer perimeter of the device when in use. Again, the effect only occurs on the outer perimeter of the device and the device does not cover a substantial portion of the plantar surface of the foot.

WO 2006/056931 provides an insert for proprioceptive and reflexology stimulation. The insert comprises a plurality of stimulation members that both act to stimulate the foot of the user and deform under the action of the user.

It has been found that structures applying increased pressure to the sole of the foot of a subject can provide a long term increase in proprioception of the subject. Accordingly, the present invention provides an apparatus for enhancing proprioception in the plantar surface of the foot without causing the brain to adapt to, and thus ignore, the enhanced signal from the nerve endings of the plantar surface.

According to the present invention, there is provided an apparatus for enhancing proprioception in the foot of a subject comprising: a member having a surface for contacting the sole of the foot of the subject; and structures disposed on the surface of the member for applying increased pressure to a region of the subjects foot whilst in use, thereby increasing the proprioception of the subject.

The apparatus may be incorporated into a form of footwear, for example, the apparatus may be used to form the actual sole of the footwear, or be incorporated into the sole of the footwear in some way. The apparatus may also be in the form of an insole, for insertion into the chosen footwear of the subject.

The apparatus is manufactured from a suitable material that is flexible enough so as to allow a large area of contact with the plantar surface, whilst maintaining the ability to support the plantar surface. The material may be a gel-type material, preferably of the silicone gel variety, or may be manufactured from a polyurethane (PU), which may, or may not be filled in order to provide the flexibility required, so as to not cause aggravation to any area of the plantar surface.

The apparatus may further comprise a fascial groove. The groove features on the apparatus where the fascial tendon meets the upper surface of the apparatus. The groove allows the soft tissues of the plantar surface to move during normal motion of the foot, so that the orthosis does not impede the normal walking action of the subject.

The enhanced proprioception claimed by the current invention is achieved by specific positioning of the aforementioned structures. The structures are placed within various dermatomes of the plantar surface. A dermatome is an area of skin innervated by sensory fibres from a single spinal nerve. By targeting certain nerve endings in the plantar surface in this way, it is possible to enhance the proprioception of the subject. The dermatomes this apparatus is concerned with include, but are not limited to, the saphenous/medial plantar, this is located on the inner area of the plantar surface, near the big toe, the sural/lateral plantar, this is located on the outer area of the plantar surface, near the little toe, and the calcaneal, this is the area surrounding the bottom of the heel.

The structures may have any suitable form to provide the required stimulation of the nerve endings in the foot of the user, but without providing the user with undue discomfort or pain. In particular, the structures may take the form of raised portions of the surface of the member. The raised portions may have any suitable shape, for example being rounder, hemispherical, and/or angular protrusions, such as rectangular slabs or conical or pyramidal protusions. As noted, the structures may be the same or of different height, according to their position on the member. The structures may be arranged in any suitable pattern, for example randomly, such as in the form of random slabs, a single line or a plurality of lines. Alternatively, the structures may have the form of recesses in the surface of the member. Again, the recesses may have any suitable form, such as rounded, hemispherical, angular, pyramidal, conical and the like. The member may comprise a single form of structure of a mixture of two or more of the aforementioned structures.

The proprioception of the subject will be enhanced by the structures mentioned above. The structures may feature at different heights over the surface of the member within the previously specified dermatomes in order to stimulate the various nerve endings with the purpose of enhancing proprioception of the subject. The different heights provide a variable surface for contact with the foot. The structures provide an overall uniform effect on the foot of the user, and the proprioception of the subject will be enhanced because of the difference in height of the structures. The structures are preferably disposed on the member so as to have the effect of feeling different to the user, depending on whether the foot is undergoing pronation (the inward roll of the foot), supination (the opposite of pronation, where the foot does not roll inwards enough), inversion (turning the foot laterally, so the plantar surface faces inwards), or eversion (turning the foot laterally, so the plantar surface faces outwards). This will prevent the brain from becoming insensitive to the nerve stimulation caused by the structures, and therefore prevent the brain ignoring signals from the nerve endings in the specific dermatomes.

The apparatus extends under the calcaneus of the foot; this is the quadrangular bone at the back of the tarsus, also known as the heel bone. The apparatus fits under the calcaneus and provides support for this bone by filling the space beneath it. The calcaneus is covered with a fat pad, commonly referred to as the heel. The apparatus preferably comprises means for cushioning the calcaneus. In the region of the apparatus below the calcaneus, there is preferably a cavity or hole, which is preferably filled with a material that is softer than that of the body of the apparatus, so as to provide cushioning for the padded surface of the calcaneus.

The structures are preferably sufficiently rigid as not to substantially deform under the weight or action of the foot of the user, for example when standing or walking. In this way, with rigid structures, the enhancement of the proprioception of the user is not diminished or lost in times of activity or when the user applies significant force through their feet.

Embodiments of the present invention will now be described, by way of example only, having reference to the accompanying drawings, in which:

Figure 1 is a representation of the apparatus for use with the left foot.

Figure 2 is a cross-sectional view of the apparatus in use.

Figures 3a , 3b and 3c are representations of the apparatus for use with the left foot showing the cones, randomly angled slab protrusions and circular recesses respectively.

Embodiments of the present invention will be described with regard to an insert for footwear. However, it is to be understood that the invention applies to the case where the apparatus forms the sole of a shoe or is combined with the sole of a shoe in some way as hereinbefore described.

Referring to Figure 1 , there is shown an embodiment of the apparatus for enhancing proprioception of a subject, generally indicated as 2. There is shown the big toe 4, and the little toe 6, shown so as to give an indication of where the dermatomes lie on the plantar surface of the foot. It is to be understood that the present invention does not extend under the toes. The area 8 under the big toe 6 is the saphenous zone. The area adjacent to this is the medial plantar dermatome 9. The area 10, under the little toe 6, is the sural dermatome. The lateral plantar dermatome 11 is adjacent to both the medial plantar and sural dermatomes. The area 12, between areas 8 and 9, is the plantar fascial groove. The area 14 is the calcaneal dermatome. The hole 16 features beneath the calcaneus, which is filled with a softer material than that that makes up the body of the apparatus.

Referring to Figure 2, there is shown a cross-sectional representation of the bones of the foot and lower leg. The tibia 102 and fibula 104 connect with the talus 106. The talus 106 then connects with the calcaneus 108. The edge of the calcaneus is supported by the apparatus 110, as shown in the diagram. The apparatus 110 fills the gap that would otherwise feature at the side of the calcaneus, thus the apparatus provides the calcaneus with support.

Referring to each of Figures 3a, 3b and 3c, there is shown an embodiment of the apparatus for enhancing proprioception of a subject, generally indicated as 2. The protrusions in Figure 3a are in the form of cones, disposed in the region of the apparatus corresponding to the saphenous zone 8, the medial plantar dermatome 9, and the sural dermatome 10 of the foot of the subject. The cones are shown as being of substantially the same height and dimensions. However, it is to be understood that the cones may differ in size, in particular height, across one or more of the zones.

Figure 3b shows a similar arrangement to that of Figure 3a, with the cones replaced by randomly angled slabs in the aforementioned regions. Again, the size and height of the slabs may be varied across the apparatus to achieve the desired enhancement of proprioception in the subject.

Finally, Figure 3c shows a similar arrangement to that of Figures 3a and 3b, with the cones and slabs being replaced by recesses or dimples in the surface of the member. The size and depth of the recesses may be varied within one region or zone, or across several different zones, as required.

In use, the apparatus is flexible enough so as to easily mould to the sole of the shoe of the subject, and also the plantar surface of the foot. The apparatus may come in different sizes in order to fit the foot of the subject, or it may be manufactured in a limited number of sizes, or even only one size, which can then by trimmed to fit the foot of the subject as desired.