Patent Publication Number: US-2001000369-A1

Title: Insole

Description:
BACKGROUND OF THE INVENTION  
       1. The present invention relates to an insole for individuals with a high arch or supinated foot type.  
       2. During walking or running, the arch of a normal foot flattens to a certain extent. Flattening of the arch is one of the body&#39;s mechanisms for dissipating or reducing shock to the foot and lower extremities such as the ankle, leg, thigh and the back. However, in certain individuals known as supinators, the arch is high and can be fairly rigid. The high arch of a supinator&#39;s foot can resist flattening upon walking or running, causing the weight and force of the body to be unequally distributed over the length of the foot. This unequal distribution of weight and force over the length of the foot during walking or running causes shock and trauma that is transmitted up the leg and back, causing numerous painful symptoms. Symptoms associated with supination or high arches include shin splints, knee pain, lower back pain, arch fatigue and heel pain.  
       3. In a contrasting class of individuals, known as hyperpronators, the foot has an arch which can flatten excessively upon walking or running, so that most of the sole makes contact with the ground. These individuals are often described as “flat-footed.” Hyperpronation or flattening of the longitudinal arch of the foot is associated with the development of symptoms intrinsic to the foot. Symptoms for hyperpronators are often the same symptoms associated for supinators. Such symptoms include shin splints, knee pain, lower back pain, arch fatigue and heel pain, and can also include other symptoms such as heel spurs and bunions.  
       4. U.S. Pat. No. 5,174,052 to Schoenhaus et. al. teach a removable innersole for controlling hyperpronation (i.e., excessive foot rotation) in hyperpronators who are flat-footed. However, this reference does not teach or suggest the use of this innersole for supinators.  
       5. Accordingly, an approach was sought to treat supinators having high arches.  
       SUMMARY OF THE INVENTION  
       6. In one embodiment, the present invention is directed towards an insole comprising a deep heel cup, and high medial and lateral flanges extending from said heel cup, wherein said heel cup cups the calcaneous of a foot in approximately a neutral degree of varus so that the insole does not induce locking of the midtarsal joint, and said high medial and lateral flanges extend continuously high along the medial and lateral sides of the insole substantially to the first and fifth metatarsal necks of the foot.  
       7. In another embodiment, the present invention is directed toward a method for treating an individual having a supinated foot type. The method comprises supplying to said individual an insole comprising a deep heel cup, and high medial and lateral flanges extending from said heel cup, wherein said heel cup cups the calcaneous of a foot in approximately a neutral degree of varus so that the insole does not induce locking of the midtarsal joint, and said high medial and lateral flanges extend continuously high along the medial and lateral sides of the insole substantially to the first and fifth metatarsal necks of the foot; and having such individual wear said insole.  
       8. The present insole can have from 1 to 5 layers or more. Optionally, the innersole can have a recess in the bottom surface of the heel cup. The recess can optionally be occupied by a suitable shock absorbing material.  
       9. The construction of the present insole, with its high medial and lateral flanges and its deep heel cup holding the calcaneous in a neutral degree of varus, serve to distribute the weight and force generated during walking and running more evenly thorough a stride, thereby causing the supinating foot to more normally absorb the shock and trauma.  
       10. The present invention has the advantage of providing an insole which is useful particularly for treating supinators and the symptoms associated with supination or high arches, i.e., shin splints, knee pain, lower back pain, arch fatigue and heel pain.  
       11. Another advantage of the present invention is that it provides an insole whose heel cup is constructed to additionally reduce or lessen the shock resulting from the heel strike of the foot.  
       12. And yet in another embodiment of the present invention is provided an insole having an shock absorbing insert in the heel portion to further enhance the inherent shock absorbing capacity of the heel cup.  
       13. In summary, the present invention provides an insole for a supinated foot, containing a number of elements in a unique combination, that mitigates shock at heel strike and evenly distributes weight and force while walking or running throughout a stride, thus reducing or lessening the painful symptoms associated with a supinated foot type.  
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     14. In order to more fully understand the invention, reference can be made to the following specification taken in connection with the attached drawings wherein:  
     15.FIG. 1 is the top view of a skeletal left foot with the insole in place.  
     16.FIG. 2 is a bottom view of the skeletal left foot with the insole of FIG. 1 in place.  
     17.FIG. 3 is a lateral side view of the insole of FIG. 1.  
     18.FIG. 4 is a medial side view of the insole of FIG. 1.  
     19.FIG. 5 is a rear view of the insole of FIG. 1.  
     20.FIG. 6 shows an enlarged cross sectional rear view of the insole of FIGS. 1 and 2 taken across the heel cup at points a-a′, illustrating measurement of the neutral degree of varus.  
     21.FIG. 7 shows an enlarged cross sectional rear view of the insole of FIGS. 1 and 2 taken across the heel cup at points a-a′, having a multilayered construction, a recess, and additionally, a heel insert.  
     22.FIG. 8 is a rear view of a left foot in insole  2 .  
    
    
     23.FIG. 1 is a top view of insole  2  having a high medial flange  6 , high lateral flange  4 , which extend continuously high along the medial and lateral sides of insole  2 , substantially or proximal to the first metatarsal neck  20  and fifth metatarsal neck  22 , respectively, of the skeletal left foot. Medial flange  6  and lateral flange  4  together prevent spreading of the foot as weight moves from calcaneous  24  to the ends of the metatarsals. Insole  2  also has a cupped heel portion  8  which cups the calcaneous  24  in approximately a neutral degree of varus. A line connecting points a and a′ (i.e., a-a′) corresponds to a cross sectional slice (as shown in FIGS. 6 and 7) taken across heel cup  8 .  
     24.FIG. 2 is a bottom view of insole  2  having medial flange  6 , lateral flange  4 , which extend continuously high along the medial and lateral sides of insole  2 , substantially or proximal to first metatarsal neck  20  and fifth metatarsal neck  22 , respectively, of the skeletal left foot. Line a′-a across bottom  13  of cupped heel portion  8 , corresponds to a cross sectional slice (as shown in FIGS. 6 and 7) taken across heel cup  8  (as shown in FIG. 1). Point  12  points to the bottom of the U-shape cutout in insole  2  which partially distinguishes medial flange  6  from lateral flange  4 .  
     25.FIG. 3 is a lateral side view of insole  2 . The lateral side view shows lateral flange  4  having a forward portion  4   a . Behind lateral flange  4  is medial flange  6  having forward portion  6   a . Also shown is a lateral side view of cupped heel portion  8 .  
     26.FIG. 4 is a medial side view of insole  2 . The medial side view shows medial flange  6  having forward portion  6   a . Behind medial flange  6  is lateral flange  4 . Also shown is a medial side view of cupped heel portion  8 .  
     27.FIG. 5 is a rear view of insole  2 , including cupped heel portion  8 , lateral flange  4  and medial flange  6  with its forward portion  6   a.    
     28.FIG. 6 is a cross sectional view of insole  2  in FIGS. 1 and 2 taken along points a-a′ in the heel cup portion having an upper surface  14 . The approximately neutral degree of varus is achieved by making thickness x-x′ of medial side  6  about the same, or slightly thinner or thicker than the thickness y-y′ of lateral side  4 , so that when worn, the insole does not induce locking of the midtarsal joint. Thickness v-v′ corresponds to the thickness of the heel portion approximately at midpoint q along line a-a′.  
     29.FIG. 7 is a cross sectional view of insole  2  in FIGS. 1 and 2 taken along points a-a′ in the heel cup portion, with lateral side  4  and medial side  6  for reference. Top cover layer  30  is bonded to layer  32  in a multilayered composite of layers  30 ,  32 ,  34 ,  36  and  38 . Layer  38  has a recess  40 . As indicated by the dash lines, recess  40  can extend into the above layers  30 ,  32 ,  34 ,  36  and  38 . In this embodiment, heel insert  42  is imbedded in recess  40  within layer  38 . Alternatively, where recess  40  is extended deeper into the layers, heel insert  42  can be imbedded to the depth provided by recess  40 . In the embodiment shown, the surface of heel insert  42  protrudes beyond bottom surface  13 . Alternatively, heel insert  42  can be flush or even slightly recessed with the bottom surface  13  of the heel cup.  
     30.FIG. 8 is a rear view of a left foot  48  in insole  2  showing lateral side  4 , medial side  6  and heel cup  8 . Not shown are the equal thicknesses of the medial and lateral sides as shown in FIG. 6. In this particular embodiment, heel cup  8  cups the calcaneous in a zero degree of varus so that insole  2  does not induce locking of the midtarsal joint. As a result, vertical axis  44 , which bisects Achilles tendon  52  attached to heel  24 , is perpendicular to horizontal axis  46  which parallels a level floor or flat, level surface  50 .  
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
     31. In the present specification, the terms “insole” or “innersole” are considered to be synonymous and interchangeable.  
     32. Preferably, the present innersole can be readily inserted into or removed from the interior of a shoe. Alternatively, the present insole can be directly incorporated as a permanent part of the construction of a shoe, such as a walking or running shoe.  
     33. The present invention provides an insole having, inter alia, a deep heel cup which can cup the heel bone or calcaneous of a supinated foot in approximately a neutral degree of varus, which may be slightly negatively posted to greater than −3 degrees of varus or slightly positively posted to less than 3 degrees of varus. Referring to FIG. 6, a slightly negative posting of greater than minus 3 degrees of varus, e.g., about −2 or −1, can be achieved by making thickness x-x′ slightly less than thickness y-y′. Conversely, a slightly positive posting of less than 3 degrees of varus, e.g., about 1 or 2, can be achieved by making thickness x-x′ slightly greater than thickness y-y′. An exactly neutral degree of varus, e.g., zero, can be achieved by making thickness y-y′ the same thickness as thickness x-x′.  
     34. The central cutout in the insole partially distinguishes the medial flange and the lateral flange. Preferably the cutout is U-shaped. The location of the cutout can vary, depending upon the insole size and intended degree of functioning for the medial and lateral flanges. The cutout is preferably centered at a location proximal to the midpoint across the width of the insole. Lengthwise, the cutout preferably can begin at a point in the heel cup forward of the calcaneous or can begin at any point along the length of the foot&#39;s arch. The cutout allows each flange to move or function independently of the other, thus allowing the medial and lateral portions of the foot to more evenly distribute the body&#39;s weight and force during each stride.  
     35. U.S. Pat. No. 5,174,052 teaches an orthotic device which, when placed in a shoe (or the shoe is built to have the shape of the interior of the device), maintains the calcaneous in a 5 degree inversion, thus locking the midtarsal joint to hold the arch. However, in persons having supinated feet, this five degree inversion may hypersupinate the foot, thus exacerbating lower extremity and foot symptoms, such as shin splints, knee pain, lower back pain, arch fatigue and heel pain.  
     36. The insole of the present invention can be formed by molding semi-rigid material to the approximate shape as shown in the figures. Preferably the exterior of the present insole is more semi-rigid than its interior, so as to maintain the desired shape during wear in a shoe. This semi-rigid molding can have a varying rigidity, e.g., a more rigid exterior to maintain the shape of the heel cup, the medial flange and the lateral flange, and a less rigid interior to cushion the foot. Such a varying rigidity can be conveniently created by using a compressible heatset foam whose rigidity is a function of the degree of compression during molding. In addition, the thickness of the individual medial and/or lateral flange may be increased or decreased to provide varying flexibility and/or rigidity for each flange. The density and/or formulation can be increased or decreased to vary the cushioning, flexibility and rigidity for each portion of the insole.  
     37. Optionally, the insole can have a recess or aperture on the top surface of the heel that comes in contact with the foot or the bottom of the heel cup that comes in contact with the shoe. Preferably, the recess is located on the bottom of the heel cup. Alternatively, one or more recesses can be located on the other parts of the insole, such as on the top surface of the medial and/or lateral flange that comes in contact with the foot or on the bottom surface of the medial and/or lateral flange that comes in contact with the shoe, so as to provide additional shock absorption for a supinated foot. Preferably, the recess is occupied with a material suitable for receiving or mitigating shock upon an individual&#39;s heel striking the floor or ground. The recess and/or shock absorbing material can be of any suitable shape, e.g., circular, triangular, star-shaped, rectangular, oval, squared or oblate. The depth or thickness of the recess and/or shock absorbing material can range from about 10 to about 250 mils (thousands of an inch), more preferably from about 90 to about 150 mils. Where a shock absorbing material is employed, it can be adhered to the recess in the insole using any suitable means, such as with adhesives, laminates, velcro attachments, welding, staples, stitches and rivets.  
     38. The insole and/or shock absorbing material can be made of any suitable material, such as polyurethane, polyurea, solid rubber, microcellular rubber, resin rubber, polysiloxanes, polyvinyl chloride, ethyl vinyl acetate, polyethylene or combinations thereof.  
     39. The insole of the present invention can be worn in casual, dress, walking or running shoes for a time effective to increase comfort of the supinated foot and/or to treat the symptoms associated with supinated feet.