Anti-valgus Heal Stabilizer

Abstract

A device and method of use of the device which supports a patient’s medial tubercle and thus resisting heel bone rotation. It features a generally wedge shape component configured to be added on top of a surface at a heal region of a shoe. The wedge shape component has a height ranging from a maximum on an inner, medial heel portion and tapers to become flush with the surface at the midline of the heal region of the shoe.

Description

BACKGROUND

For our purposes, the relevant bone of the foot are (1) the calcaneus, (2) the talus and (3) the navicular as illustrated in FIG. 1. The calcaneus, also known as the heel bone, is the strongest and largest bone of the foot and is the first bone to come into contact with the weightbearing surface. The talus, or ankle bone, has lower surfaces that articulate with upper surfaces of the calcaneus. The navicular is the primary arch bone.

Walking is divided into two parts. The swing phase is when the foot is in the air without any body weight acting on the foot structure. The contact phase is when the foot makes touches the weightbearing surface. The forces from the body above combined with the ground reaction forces from below will act on the osseous structures within the foot. Ligaments, muscles, and tendons will make secondary contributions to the stability and function of the foot during stranding, walking, running, and jumping.

The outer heel is the first part of the foot to make contact during walking. The forces from the weightbearing surface push up against the heel and the weight from the body above pushes against the top middle portion of the heel bone, the talocalcaneal posterior facets. The weightbearing forces continue to travel from the outer heel through the center of the hindfoot, to the midfoot, forefoot, and finally the bottom of the toes.

The stability and alignment of the articular surfaces of the bones of the hindfoot is crucial for an efficient walking cycle. An orthopedic pathology called, Recurrent Talo Tarsal Dislocation (RTTJD), is a condition where the normal stability of the hindfoot bones is lost resulting in excessive hindfoot motion. This condition, RTTJD, results in the partial dislocation of the ankle and heel bones. The articular joint facets between the two bones no longer remain in constant congruent contact.

The ankle bone is the primary deforming force. It shifts from its natural position on the heel bone by dropping downward, forward, and inward. The heel bone will react to the abnormal ankle bone motion by slightly rotating outward. This occurs because the forces that should be acting on the joint facets toward the back of the heel, the posterior talocalcaneal joint, are now acting toward the inner front of the heel bone. This outward rotation, movement of the heel is referred to as valgus, as opposed to varus where the ankle of the back of the heel is turned toward the mid-line of the body.

One of the other visible signs of RTTJD is its effect the navicular, the arch bone. The ankle bone displacement pushes against the arch bone in a manner that causes the arch bone to drop. This leads to a lowering of the inner arch, called a flat foot. When the ankle bone is repositioned on the heel bone, the arch bone will be in its normal position and the arch will also appear “normal.”

RTTJD is a very common pathology but, it is rarely referred to by its orthopedic description. There have been many names given to this condition including flatfoot, flexible flatfoot, fallen arches, adult acquired flatfoot, and weak foot. One of the most common names is called over-pronation or hyperpronation. The loss of stability of the hindfoot bones results in the combination of foot motions called pronation. This is opposed to the opposite motion-position of the foot bones called supination. Pronation results in a weakening of the foot, whereas supination results in a strengthening of the joints of the foot. There should only be a very insignificant amount of pronation as the entire bottom portion of the foot contacts the weightbearing surface. This allows for the foot to compensate for an uneven weightbearing surface. Supination stiffens the foot to provide a stable lever-arm for the rest of the gait cycle.

RTTJD leads to an extended period of a weakened joints within the foot, over-pronation. The joints should be locked and strong to get ready for the forces that will act on them. However, because they are in a weakened stated, the ligaments, muscles, and tendons will have excessive strain acting on them to compensate for the excessive force. Eventually, the excessive force will take their toll due to the repetitive micro-trauma inflicted by the thousands of steps taken every day and tens of millions of steps over the years.

One of the most common forms of treatment for over-pronation is the use of shoe modifications. Specifically, the insertion of an insert into the shoe is the first recommended treatment. These shoe inserts range from over-the-counter generic arch supports to custom-made foot orthosis. There have been many designs and claims made of these “arch” supports throughout the past many decades. However, there has been one key element that has not been incorporated to any of the pre-existing art.

All of the present-day arch supports, whether over-the-counter or custom-made has missed a key element in their design. The present devices are “arch” supports -their function is to push up against the arch. Their function is aimed at the arch bone. When someone walks with an “arch” support on their shoe that support attempts to counter the drop of the arch bone by pushing up against it. There is no radiographic data to show that the arch support actually prevents the arch bone from dropping. A primary design flaw with the arch supports is that they are reactive not proactive. The arch supports try to limit navicular drop after the navicular bone is already being force downward.

There is a naturally occurring space between the ankle and heel bones called the sinus tarsi. This naturally occurring osseous chamber acts as a dividing line between the forces that should be acting on the back of the heel against the forces that should be acting toward the front of the foot. The sinus tarsi is obliquely oriented to allow the weightbearing forces to stay balanced between the back of the heel and the front of the foot. RTTJD disrupts that balance before the entire bottom of the foot touches the weightbearing surface. By the time the arch of the foot comes into contact with the “arch” support the navicular bone has been pushed out of its normal alignment. The heel will be turned into valgus, and the forefoot also will be forced into valgus. Arch supports function to support the part of the foot in front of the sinus tarsi, they have no effect to the back of the heel.

The “heel cup” portion of the arch supports is the upper top area that comes into contact with the heel. This area is concave from side-to-side and front to back in all arch supports but over-the-counter and custom-made. Some of the devices claim to have a superior “cup” shape to control or counter-heel valgus, but the shape of this area is always concave both front-to-back and side-to-side. There is no data to prove a “heel-cup”, no matter the size, has any ability to prevent or reverse ankle bone displacement on the heel bone.

SUMMARY OF THE INVENTION

The invention is a wedged shaped modification made to the top inner heel portion of a shoe or shoe insert for the purpose of reducing excessive excursion, or excessive outward, backward movement of the heel bone.

SUMMARY OF THE DRAWINGS

FIG. 1 illustrates the bones of the foot with the three bones labeled (N = Navicular; T = Talus; C = Calcaneus) that are most relevant here.

FIG. 2A is a left foot top view of a preferred embodiment of the invention.

FIG. 2B is a left foot bottom view.

FIG. 2C is a right foot side view.

FIG. 2D is a right foot front view.

FIG. 2E is a right foot rear view.

DETAILED DESCRIPTION

In anatomic terms the invention is an Anti Valgus Heel Stabilizer (AVHS) 100 as shown in FIG. 2A. The wedged shape component 120 provides the primary corrective force. As shown in FIG. 2A, the wedge 120 is added to the inner top portion of the heel cup area of a shoe or shoe insert. The wedge is thicker on the inner, medial portion of the heel 140, 160 and thinner toward the center of the heel 180. The wedge begins at the back of the heel up area and extends toward the front-end of the heel. There are a wide range of wedge shape angles, depending on the amount of inner heel stabilizing required. In one preferred embodiment a minimum slope is employed. The thicker portion is about 1 mm to 5 mm and tapers down to zero toward the center of the heal.

In another preferred embodiment the thicker portion is about 5 mm to 10 mm and tapers down to zero toward the center of the heal.

In still another preferred embodiment, the thicker portion is about 10 to 25 mm and tapers down to zero toward the center of the heal.

In each case this wedge imparts an inward force to the heal on its medial side.

There are two anatomic landmarks on the bottom of the heel, medial and lateral plantar tubercles. These bony projections serve as attachment points to muscles and fascia. The inner medial tubercle is much larger than the lateral tubercle. There is a reason for the difference in size between the two. The smaller lateral tubercle allows for a slight inversion of the heel at heel strike. As the rest of the foot drops to the weightbearing surface the larger inner tubercle contacts the ground helping to redirect the weightbearing forces to the front of the foot. RTTJD alters the direction of that force causing a rotation of the back of the heel.

The function of the AVHS is to provide angular support to the medial tubercle to resist heel bone rotation. The AVHS provides support for the back area of the sinus tarsi unlike the arch support 110 that supports the area in front of the sinus tarsi. The AVHS is meant as an addition to the arch support so that there would be support from the inner heel to the end of the long first metatarsal bone. The addition of the AVHS would provide proactive measure because it is altering heel mechanics prior to the ankle bone displacement rather than acting after the ankle bone has already displaced. The AVHS is function before the excessive forces are acting on the arch bone. The combination of both will provide beneficiaries with a dual form of treatment.

Claims

1. An anti valgus heel stabilizer, useful for supporting a patient’s medial tubercle and thus resisting heel bone rotation, comprising:

a generally wedge shape component configured to be added on top of a surface at a heal region of a shoe,

the wedge shape component has a height ranging from a maximum on an inner, medial heel portion and tapers to become flush with the surface at the midline of the heal region of the shoe.

2. The anti valgus heel stabilizer as defined in claim 1, further comprising the stabilizer added to the shoe as part of a shoe insert.

3. The anti valgus heel stabilizer as defined in claim 1, further comprising the stabilizer added to the shoe during shoe manufacture.

4. The anti valgus heel stabilizer as defined in claim 1 wherein the wedge shape maximum height further comprises a range from 1 mm to 5 mm.

5. The anti valgus heel stabilizer as defined in claim 1 wherein the sedge shape maximum height further comprises a range from 5 mm to 10 mm.

6. The anti valgus heel stabilizer as defined in claim 1 wherein the sedge shape maximum height further comprises a range from 10 mm to 25 mm.

7. A method of heel stabilization comprising the use of an anti valgus heel stabilizer of claim 1.