Abstract:
A heel lift assembly is provided for use in a variety of types of footwear including open toed and open heeled footwear. Such a heel lift assembly comprises a plurality of assorted removable and interchangeable heel lifts which may be worn alone or used together with an insole and outsole combination which are part of an open toed and/or open heeled shoe assembly. The plurality of interchangeable and removable heel lifts are connected to each other by an assembly using grooves on the bottom of each heel lift and one or more attachment points on the upper surface of the each subsequent heel lift.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims benefit of U.S. Provisional Patent Application No. 61/937,668 filed Feb. 10, 2014, the contents of which are herein incorporated by reference in their entirety. 
     
    
     BACKGROUND 
       [0002]    Leg length inequality can be divided into two categories: functional inequality, in which the legs are actually the same length but some other inequality such as pelvic obliquity creates the appearance of leg length inequality, and actual inequality in which there is an anatomical difference in the length of the legs. Between 40 to 70% of the general population has an inequality of 5 mm or more (Knutson, Gary A. “Anatomic and Functional Leg-Length Inequality: A Review and Recommendation for Clinical Decision-Making. Part I, Anatomic Leg-Length Inequality: Prevalence, Magnitude, Effects and Clinical Significance.” Chiropractic &amp; Osteopathy 13 (2005)) and approximately 1 in 1,000 people use a corrective device. (Guichet J M, Spivak J M, Trouilloud P, et al: Lower limb-length discrepancy. an epidemiologic study. Clin Orthop 272:235-241, 1991). 
         [0003]    The spine, pelvis and lower extremities compensate for leg length asymmetry by shifting the center of gravity. Common compensations include coronal pelvic tilt, lumbar scoliosis, knee flexion, genu recuvatum, subtalar joint pronation, ankle plantar flexion and foot supination. These compensations can cause backache, pain, premature degenerative arthritis, flank pain, arthritis, psoasitis, arthritis of the hip, patellar tendinitis, patellofemoral pain syndrome, plantar fasciitis, medial tibial stress syndrome, metarsalgia illotibial band syndrome with knee pain, trochanteric bursitis, sacroiliac discomfort, Achilles tendinitis and cuboid syndrome. Additionally, physical compensation for leg length inequality can lead to further orthopedic complications such as degenerative arthritis, full spinal scoliosis, and/or lower back pain. 
         [0004]    While technology exists to address leg length discrepancy, there are problems with patient compliance frequently due to discomfort, fitting limitations, and appearance of the heel lift. Additionally, conventional heel lifts have problems with slippage or inflexibility during the “toe off” part of the gait cycle. Traditional heel lifts are designed to only fit a narrow selection of shoes, namely lace up shoes, loafers, or other flat shoes with quarters and counters and not the wide variety of shoes currently on the market. Given the problems with patient compliance and the inability to use traditional heel lifts with a wide variety of shoes, there is a need for alternate heel lifts. 
       BRIEF SUMMARY 
       [0005]    Disclosed is a variable removable heel lift assembly for use alone or in combination with a sandal designed to incorporate the variable removable heel lift. Such a heel lift may be used to correct both functional and actual leg length inequality, both of which shift the center of gravity causing further orthopedic complications. 
         [0006]    Leg length inequality may be measured by any means generally used including clinical and radiographic means. Once the difference in the leg lengths is determined, an individual may be fitted with a heel lift of sufficient height to compensate for the difference in the leg lengths resulting in a right and left leg of substantially equal length. 
         [0007]    The variable removable heel lift assembly described here comprises a series of one or more heel lifts that may be placed above or underneath an insole. In some embodiments, the insole may include a thickened heel portion which forms part of the variable removable heel lift assembly. The heel lifts that make up the variable removable heel lift assembly may be the same or different heights, thicknesses, and/or materials and may have the same or different surfaces. In some embodiments, the uppermost heel lift may have a substantially flat first surface and a divided recessed second surface. Subsequent heel lifts may have a series of protrusion connection points that fit into the divided recessed second surface of the heel lift above. Such protrusion connection points may be designed to hold the individual heel lifts together to form the variable removable heel lift assembly. In some embodiments, the first heel lift may also have a series of protrusion connection points. Such protrusion connection points may additionally have therapeutic benefits such as massage, pressure or acupressure points. In some embodiments, the upper surface of the heel lifts may be substantially smooth or may be textured to create a non-slip or fashionable surface. In some embodiments, an additional material may be affixed to the raised portion of the divided recessed second surface to provide additional aid in keeping the variable removable heel lift assembly in place in a shoe. 
         [0008]    Each heel lift in the variable removable heel lift assembly may be the same or different heights which together correct the leg length inequality in an individual. In some embodiments, the uppermost heel lift in the variable removable heel lift assembly may be thinner than subsequent heel lifts. Heel lift thicknesses may range from 1 mm to 12 mm at the thickest point including heel heights of 3 mm, 5 mm, 7 mm, 9 mm and 12 mm. The slope of the variable removable heel lift assembly may be no greater than 5.5 degrees. In some embodiments, the slope of the variable removable heel lift assembly may be between about 0.5 to about 5.5 degrees. In other embodiments, the uppermost heel lift may be softer and/or more compressible than subsequent heel lifts in the heel lift assembly. In some embodiments the uppermost heel lift may include a heel cup. 
         [0009]    The variable removable heel lift assembly may be used in any type of shoe desired. In some embodiments, it may be part of shoe designed to contain the variable removable heel lift assembly. Such a shoe may include an outsole with a recessed inner opening, an insole with a series of depressions along the bottom, an upper which wraps around the outer edge of the insole, and the variable removable heel lift assembly below the insole, held in place and hidden by the raised heel of the outsole. Additional features and advantages will be better understood in view of the detailed description provided below. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0010]    To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the figure number in which that element is first introduced. 
           [0011]      FIG. 1  is a top view of an embodiment of a heel lift. 
           [0012]      FIG. 2  is an exploded view of an embodiment of a heel lift assembly. 
           [0013]      FIG. 3  is a top view of an embodiment of a heel lift. 
           [0014]      FIG. 4  is a bottom view of an embodiment of a heel lift. 
           [0015]      FIG. 5  is an embodiment of a heel lift attachment point. 
           [0016]      FIG. 6  is a rear view of an embodiment of a heel lift assembly. 
           [0017]      FIG. 7  is a top view of an outsole. 
           [0018]      FIG. 8  is a side view of an embodiment of an outsole. 
           [0019]      FIG. 9  is a rearview of an embodiment of an outsole. 
           [0020]      FIG. 10  is a bottom view of an embodiment of an insole. 
           [0021]      FIG. 11  is a top view of an embodiment of an insole. 
           [0022]      FIG. 12  is a side view of an embodiment of an insole. 
           [0023]      FIG. 13  is an exploded view of an embodiment of a slide style shoe. 
           [0024]      FIG. 14  is a top view of an embodiment of an assembled slide style shoe. 
           [0025]      FIGS. 15  A and B are sectional views of an embodiment of a slide shoe without (A) and with (B) a heel lift assembly. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    Leg length inequality affects up to 70% of the population. Legs may be slightly different lengths because of genetics, infection, surgical interventions (knee replacements, hip replacements) or accidents. For many people a slight inequality, usually less than 5 mm, does not cause any noticeable problems. However, for those with a larger inequality, leg asymmetry can change a person&#39;s gait and alter the forces acting on the body as an individual walks or runs, increasing the risk of osteoarthritis in the knee and hip, generating low back pain, and creating stress fractures. In addition, functional scoliosis, posture deformation and discopathy may occur, causing postural issues throughout the spine. 
         [0027]    Leg length inequality may be determined using any method known to those of skill in the art. For example, a tape measure may be used to measure the length of each lower extremity by measuring the distance between the anterior superior iliac spine (ASIS) and the medial malleolus. In another embodiment, the pelvis of the erect patient may be leveled by placing blocks of known height under the short limb and varying the heights of the block until the pelvis is level. In a further embodiment, leg length inequality may be determined using standard radiography including orthoroentogenogram, scanogram, and teleoroentgenogram. In yet another embodiment, computed radiography, ultrasound, CT scanogram, MRI scan, or microdose digital radiography may be used to determine the difference in leg lengths in an individual. Once the difference in leg lengths in an individual is determined, a heel lift height may be chosen that is approximately equal to the difference in leg lengths. 
         [0028]    Standard heel lifts are 3 mm, 5 mm, 7 mm, 9 mm, and 12 mm with the possibility of other incremental sizes from 1 mm to 12 mm. To be effective, heel lifts should be worn at all times, however, due to difficulties in fitting standard heel lifts into a variety of shoe types, most patients do not wear their heel lifts as prescribed, resulting in back, hip, knee or other pain and degenerative wear. Described herein is a variable removable heel lift assembly that can be worn in a variety of types of shoes including, but not limited to, shoes without counters, corners, or toe boxes such as flip-flops, slides, mules, or other sandals. The variable removable heel lift assembly may additionally be worn with more traditional shoes including, but not limited to, loafers, clogs, boots, athletic shoes, flats, brogues, oxfords, derbys, heels and the like. Such heel lift assemblies may have variable widths as well as variable heights, increasing their suitability for different types of shoes and increasing the comfort of individual users. 
         [0029]    With reference to  FIG. 1 , a heel lift  104  has a first surface  106 , a bottom or second surface  108  and a height  102 , with the maximum height at the rear portion of the heel lift and the height decreasing to form a slope towards the front of the heel lift  110 . The slope of the heel lift may vary between about 0.1 and about 5.5 degrees, between about 0.5 and about 5.3 degrees, about 0.25 and about 5 degrees, or any variation thereof. In some embodiments, the heel lift may be associated with one or more additional heel lifts in order to create the desired heel height. In further embodiments, the heel lift  104  is shaped to form a heel cup with a raised back and sides. In other embodiments, the heel lift  104  has a substantially flat first surface  106  as shown in  FIG. 1 . In some embodiments, the top or first surface  106  of the heel lift  104  is smooth. In other embodiments, the first surface  106  of the heel lift  104  is textured. Such textures may be used for non-slip purposes, fashion and comfort. In additional embodiments, the first surface  106  may include a heel cup (not shown). 
         [0030]    As shown in  FIG. 2 , a heel lift assembly  202  comprises a first heel lift  104 , with one or more additional heel lifts as exemplified by  206  and  208  (progressively numbered and herein referred to as the second and third heel lift though there may be additional heel lifts as well) with the maximum height at the rear portion of the heel lift assembly and the height gradually decreasing to form a slope towards the front of the heel lift assembly. The slope of the heel lift assembly may vary between about 0.1 and about 5.5 degrees, between about 0.5 and about 5.3 degrees, about 0.25 and about 5 degrees, or any variation thereof. 
         [0031]    There may be one, two, three, four, five, six, seven, eight, or more heel lifts in the heel lift assembly. The heel lifts exemplified at  104 ,  206  and  208  may be used at any time in any order as required by the amount of individual&#39;s leg inequality and/or lumbosacral leveling. In some embodiments, the first heel lift  104  is generally found in contact with the sole of the foot of the individual with additional heel lifts such as  206  and  208  placed below the first heel lift  104 . In other embodiments, alternate heel lifts such as heel lifts  206  and  208  may be placed in contact with the sole of the foot of the individual wearing the heel lift. In some embodiments the heel lifts may have protrusion connection points  210  which serve to connect a heel lift with the heel lift above. In some embodiments, the protrusion connection points  210  may be shaped so as to provide a massage, therapeutic pressure points, acupressure points and the like or other therapeutic benefits to the sole of the foot of the individual wearing the heel lift assembly. In some embodiments, an individual may start with a single heel lift and progressively increase the thickness and/or number of heel lifts used at a time to allow the individual to become accustomed to wearing the heel lift assembly. In additional embodiments, individual heel lifts may be replaced due to wear without requiring replacement of the entire heel lift assembly. 
         [0032]    Heel lifts may be made of any material generally used, including, but not limited to cork, plastic, ethylene vinyl acetate, polyurethane foam, poron, polyurethane elastomers, single density polyurethane, polyether systems, and the like. In some embodiment, hardness is classified as medium to hard grade. Each heel lift in the heel lift assembly may be made of the same or different materials and have the same or different levels of hardness. In some embodiments, the heel lift in contact with the sole of the foot is softer and/or more flexible than a heel lift which is not in contact with the sole of the foot. In other embodiments, the heel lift in contact with the sole of the foot is harder and/or less flexible than a heel lift which is in contact with the sole of the foot. In further embodiments, the heel lift in contact with the sole of the foot may be the same hardness as other heel lifts in the heel lift assembly. The heel lifts may be the same or different heights. In some embodiments, the topmost heel lift is thinner, and/or has less heel height than other heel lifts in the heel lift assembly. In further embodiments, the topmost heel lift may be more compressible than other heel lifts in the heel lift assembly. 
         [0033]    In reference to  FIG. 3 , a first surface of exemplary second heel lift  206  may have one or more protrusion connection points  210 ,  304 , and  308  on a second heel first surface  310 . The protrusion connection points may be of any shape that is useful. In some embodiments, the protrusion connection points  210 ,  304 , and  308  may be shaped so as to provide a massage, therapeutic pressure points, acupressure points and the like or other therapeutic benefits to the sole of the foot of the individual wearing the heel lift. In other embodiments, the protrusion connection points  210 ,  304  and  308  may be any size or shape that allows the heel lifts to connect to each other and/or a shoe insole. For example, it may be a hook, snap, clip, bayonet clip, ball, adhesive, velcro fasteners, rivets, sculpted foam, shaped plastic, shaped EVA, shaped polyurethane, shaped rubber, shaped polyether systems, hook and loop tape, and socket joint, and the like. In some embodiments, the protrusion connection points may fit into the bottom of the heel lift above using a snap fit, friction fit, press fit or interference fit or the like. In additional embodiments the protrusion connection points may provide both a connection point and therapeutic benefits. 
         [0034]    The heel lifts described herein may have a second or bottom surface. As shown in  FIG. 4 , a heel lift  104  may have a second or bottom surface  412 . Such a second or bottom surface  412  may be on the second surface of some or all of the heel lifts in the heel lift assembly. In some embodiments, the bottom surface has a separation notch  408  which allows a plurality of heel lifts in an assembly of heel lifts to be separated from each other and from an outsole. The separation notch may be any shape generally desired. In some embodiments, it may be a half circle, a square, a rectangle, a trapezoid and the like. 
         [0035]    In some embodiments, the bottom surface  412  has a divider  406 . The divider  406  may divide recessed area  410  to create a divided recessed area. Divider  406  may consist of one or more straight and/or curved features, dividing the recessed area  410  into two or more spaces. Protrusion connection points  210 ,  304  and  308  in the first surface of a heel lift may be shaped to fit securely in the recessed areas  410  using any means of attachment generally used. The protrusion connection points  210 ,  304  and  308  may be any shape that allows them to fit in the recessed areas  410  including, but not limited to, circular, triangular, pie shaped, sector shaped, trapezoidal, rectangular and the like. In some embodiments, the protrusion connection points of a first heel lift may fit into the bottom of the second heel lift above using a snap fit, friction fit, press fit or interference fit and the like. In some embodiments, an adhesive, hook tape, non-slip tape, textured surface or other substance may be applied to the bottom divider  406  in the heel assembly such that the heel lift assembly sits securely in a shoe. In some embodiments, such substances may be applied to the bottom divider  406  of every heel lift in a heel lift assembly. In other embodiments, such substances may be applied only to the second surface of the heel lift in contact with the shoe. 
         [0036]    In some embodiments, as shown in  FIG. 5 , a first heel lift  502  may attach to a second heel lift  504  by fitting a protrusion connection point  506  with an opening or recessed area  508 . The protrusion connection points and corresponding openings may be any shape and number desired to ensure that the heel lifts comprising the heel assembly attach securely to one another including, but not limited circular, triangular, pie shaped, sector shaped, trapezoidal, rectangular and the like. In some embodiments, the opening or recessed area  508  may be the direct inverse of the protrusion connection point  506  or may be part of a larger opening or recessed area as shown at  410 . The protrusion connection point  506  may fit into the bottom of the heel lift above using a snap fit, friction fit, press fit or interference fit and the like. 
         [0037]    As shown in  FIG. 6 , a first heel lift  602  is stacked with a second heel lift  604  and a bottom heel lift  606 . The series of heel lifts are assembled to form a heel lift assembly. One or more heel lifts  602 ,  604  and  606  may have a separation notch  608 ,  610  and  612  respectively. The separation notch  608 ,  610  and  612  respectively allow each heel lift to be separated from another heel lift or a shoe to allow the user to adjust the height of the heel lift assembly, remove, or replace the heel lift assembly as necessary. 
         [0038]    A heel lift and/or heel lift assembly as described herein may be used on its own or may be incorporated into a shoe including shoes without counters, corners, or toe boxes such as flip-flops, mules, or other sandals. For example, as shown in  FIG. 7 , an outsole  704  may have a first depression  702  designed to incorporate an insole and heel lift. In some embodiments, the depression  702  is surrounded by a lip  718  allowing an insole to be firmly held in place. In some embodiments, the outsole may have a separation notch  708  to allow the removal of the insole and/or heel lift assembly. The outsole  704  may have additional depressions  706 ,  710 ,  712 ,  714 ,  716  which allow an upper (not shown) to wrap smoothly around the side of an insole and fit in the outsole. As shown in  FIG. 8 , the outsole  704  may have an angled heel  804  to cover the outer edge of the insole and heel lift assembly. A heel lift assembly and/or insole may be easily removed and replaced using the access zone  708  as shown in  FIG. 9 . 
         [0039]    With reference to  FIG. 10 , a footbed  1002  for a sandal type shoe is shown. The footbed  1002  has a bottom or second surface  1012 . In some embodiments, the footbed  1002  may include one or more depressions such as those shown at  1010 . These depressions are equivalent to the thickness of an upper, allowing the upper to lie flatly against the bottom of the shoe. In some embodiments, the depressions  1010  may be the same depth and/or width. In other embodiments, the depressions may be different depths and/or widths. In additional embodiments one or more of the depressions may be the same depth and/or width. Some or all of the depressions may be used with any particular upper. In some embodiments, the footbed  1002  has footbed depression areas  1008  which allow an upper to wrap around the outside of the footbed  1002  and fasten at footbed attachment points along the side of the footbed alone or in addition to attaching to attachment points  1004  in depressions  1010 . In some embodiments, the footbed  1002  may have a slit  1006  for the attachment of a strap. As can be seen on footbed  1002 , there are a plurality of depressions  1010 , footbed depression points  1008 , and footbed attachment points  1004  allowing for a variety of uppers and straps to be used with the same footbed. Some or all of the depressions, footbed depression points and footbed attachment points may be used to fasten an upper or strap to the base of the footbed. Footbed attachment point  1004  may be any size or shape that allows the upper or strap to connect to the insole. For example, it may be a hook, snap, clip, bayonet clip, ball and socket joint, ball, pin, and the like. In some embodiments the bottom surface  1012  of the footbed  1002  has a divided recessed area  1020  separated by a divider  1014  and bounded by a raised lip  1016 . Such divided recessed area  1020  is shaped such that it can accommodate protrusion connection points on a subsequent heel lift in a heel lift assembly. In addition, in some embodiments, the heel lift may include a central flex point  1018 . 
         [0040]    As shown in  FIG. 11 , the footbed  1002  has an upper surface  1104  which may be textured or smooth. In some embodiments, the upper surface  1104  may have a heel cup. The footbed depression areas  1110  are equivalent to the thickness of an upper (not shown), allowing the upper to lie flatly against the side of the shoe when placed in an outsole. In some embodiments, the depressions  1110  may be the same depth and/or width. In other embodiments, the depressions may be different depths and/or widths. A side view of the footbed  1002  is shown in  FIG. 12 , with the depressions  1110  shown as well as side attachment points  1202  and  1206 . Side attachment points  1202  and  1206  may be any size or shape that allows the upper or strap to connect to the insole. For example, it may be a hook, snap, clip, hook and loop tape, bayonet clip, ball and socket joint, and the like. In some embodiments the attachment may be permanent. In other embodiments, the attachment may be interchangeable, allowing a variety of uppers to be used with the same insole and outsole. 
         [0041]    An exploded view of an embodiment of a slide style shoe is shown at  FIG. 13 . The slide style shoe comprises an upper  1302  with upper attachment points  1312  which connect with footbed  1002  attachment points  1202 . The insole  1002  attached to the upper  1302 , sits in the outsole  704  which has a lip  718  to hold the footbed  1002  in place. A heel lift assembly under the insole would be hidden by the angled heel  804  of the outsole  704 . 
         [0042]    In the assembled view in  FIG. 14 , the upper  1302  is attached to the insole  1002  though not all outsole depression areas  706  are used. The upper  1302  and insole  1002  combination is inserted into the outsole  1402 . The access zone  708  may be used to remove and insert the footbed  1002 . It may be desirable to remove and re-insert the footbed  1002  in order to change the upper  1302  for a different style of upper and/or to insert or modify a heel lift assembly placed under the insole  1002 . 
         [0043]    A side view of a slide style shoe with ( FIG. 15A ) and without ( FIG. 15B ) a heel lift assembly is shown in  FIG. 15 . The upper  1504  is attached to an insole  1502  at footbed depression and attachment points  1506 . The insole  1502  and upper  1504  is then inserted into the outsole  1516 . The angled heel  1508  of the outsole  1516  hides the insole which is surrounded on all outer edges by the outsole  1506 . 
         [0044]    In alternate embodiments as shown in  FIG. 15  B, a heel lift or heel lift assembly  1510  may be inserted under the insole  1502  to address issues of leg length inequality. The insertion of the heel lift or heel lift assembly is such that the insole  1502  remains below the edge of the outsole  1516 , beneath the outsole lip  1514 . The upper  1504  wraps around the insole  1502  at footbed depression  1518  and attachment points  1520  and so that the upper  1504  fits snugly between the outsole depressed areas and fastens in place using attachment points  1520 . 
         [0045]    Although the invention has been described by reference to particular illustrative embodiments thereof, many changes and modifications of the invention may become apparent to those skilled in the art without departing from the spirit and scope of the invention. It is therefore intended to include within this patent all such changes and modifications as may reasonably and properly be included within the scope of the present invention&#39;s contribution to the art.