Abstract:
The present disclosure provides a custom or pre-fabricated ankle support brace providing tri-planar control of the ankle foot structure and allows for free plantar dorsi flexion. The ankle support brace comprises a stirrup-shaped brace body composed of reinforcement strips and a closure mechanism.

Description:
FIELD 
       [0001]    This disclosure relates to providing a custom or pre-fabricated ankle support brace (ASB). The ASB provides medial-lateral support yielding varus and valgus control to protect from excessive rotation or extreme medial-lateral motion that could go beyond normal end-range of motion, causing injury. The ASB protects against ankle instability or injury during normal or extreme human locomotion while allowing free plantar and dorsi flexion as well as tri-plane motion. 
       BACKGROUND 
       [0002]    Typical ankle braces use flexible materials to provide a comfortable fit and little, if any, motion restriction, and thus are very limited in support. These ASBs may not prevent injury in excessive activity associated with physical exercise programs or athletic events. ASBs which do include a combination of fabric cover with rigid or semi-rigid inserts, provide support but severely limit ankle mobility. In addition, current ASBs suffer from lack of durability, especially if the person using them is involved in aggressive athletic activity. 
         [0003]    In response to the limitations of such ASBs, the athletic industry typically uses adhesive tape to protect athletes since it provides an adequate support, but often limits mobility. However, adhesive tape is not durable and often breaks down during use. The tape is generally not reusable. Still further, before every athletic event a person needs to take the time to tape their ankle. 
         [0004]    There exists a need in improving conventional ASBs to treat acute or chronic ankle conditions without either limiting mobility or failing to provide sufficient support, while offering a level of comfort and durability suitable for intense, athletic applications that can be worn inside common civilian or athletic footwear. The improved ankle brace would be durable, reusable and provide the correct balance between support and mobility when used in conjunction with a shoe. 
       SUMMARY 
       [0005]    The present disclosure provides an ankle support brace which has a stirrup-like shape comprising a combination of a closed cell polyethylene foam inner lining bonded to a polyolefin elastomeric material, with one or more key structural thermoplastic components situated between the polyethylene foam inner lining and the outer layer of polyolefin elastomeric material. In an embodiment, a key structural thermoplastic component is wrapped around the posterior half of the proximal edge of the ankle support brace, and a second key structural thermoplastic component is structured as a stirrup-like configuration that extends as a unitary element continuously from the upper medial side to under the mid-foot and back up to the upper lateral side of the brace. 
         [0006]    Not only does the present disclosure provide an ASB composed of a combination of specific materials varied in stiffness and texture, but it provides a specific relative amount and placement of key structural thermoplastic components to yield an ankle support brace having an improved combination of support, flexibility and comfort that can be tailored to better meet the specific needs of each individual patient. 
         [0007]    In one embodiment, the disclosure provides an ASB arranged to provide varus and valgus control and medial-lateral inversion or eversion control comprising a brace body comprising a medial side portion, a lateral side portion, a medial front edge of the medial side portion, a lateral front edge of the lateral side portion, a sole portion in a plane at least partially horizontal to the medial and lateral side portions having an arch portion and a heel portion, and a back portion extending from the heel portion to a lower calf portion. In embodiments, the brace body comprises a minimum of three layers including a closed cell polyethylene foam inner layer, a rigid or semi-rigid thermoplastic intermediate layer as key structural thermoplastic components, and a polyolefin elastomeric material as an outer layer. Optionally, an additional material layer can be applied over the surface of the foam inner layer to enhance the texture and provide a soft interface with the foot, for example, a synthetic leather-like material or elastic fabric. 
         [0008]    In an embodiment, the ASB is stirrup shaped and comprises a medial stirrup-type reinforcement strip with a first end situated a distance below the proximal edge of the orthosis and extending down along the medial side portion to under the mid-foot, and continuing up the lateral side with a second end situated below the proximal edge of the brace. The brace further comprises a proximal reinforcement strip beginning on the medial side just below the proximal edge and extending around the posterior side to an end point on the lateral side. The brace further includes a closure mechanism positioned on the lateral side end of the proximal reinforcement strip and a closure mechanism positioned on the medial side end of the reinforcement strip. Multiple closure mechanisms can be situated on the lateral anterior edge and the medial anterior edge of the stirrup type reinforcement strip wherein the closure mechanisms are structured and operable to tighten and secure the ASB onto the subject&#39;s lower leg and foot. 
         [0009]    The present disclosure also provides a method of manufacturing an ASB. In an embodiment, the method comprises the steps of providing a mold of a lower extremity, forming a closed cell polyethylene foam material over the mold, cutting away portions of the foam to create openings at the heel and at the foot portion forward of the metatarsals, forming at least one key structural thermoplastic component over the closed cell polyethylene foam to bond to the foam as structural reinforcements, forming an outer layer of a polyolefin elastomeric material over the prior two layers on the mold to create a third bonded layer, setting closure mechanisms (e.g., lace loops) into the polyolefin elastomeric outer layer, and removing the mold from the material layers to produce the ASB. 
         [0010]    The ankle support brace of the disclosure is an improved alternative to traditional ankle braces, providing a broad range of features and benefits that address the limitations of traditional braces and leather ankle gauntlets. The present thermoplastic ankle support brace is hygienic, waterproof, easily cleaned, and is readily adjustable at fitting utilizing a modest heat application. The present device provides more flexible comfort with complete control, and is more durable than traditional ASBs. The device has a slim, low profile design that fits inside most shoes. The improved ASB provides a soft interface with the patient&#39;s foot to enhance comfort and alternatives for closure mechanisms. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    Preferred embodiments of the disclosure are described below with reference to the following accompanying drawings, which are for illustrative purposes only. Throughout the following views, the reference numerals will be used in the drawings, and the same reference numerals will be used throughout the several views and in the description to indicate the same or like parts. 
           [0012]      FIG. 1  is a perspective view of an embodiment of an ankle support brace according to the disclosure. 
           [0013]      FIG. 2  is a perspective view of another embodiment of an ankle support brace according to the disclosure. 
           [0014]      FIG. 3  is a medial side view of the ankle support brace of  FIG. 1  positioned inside a shoe (shown in phantom). 
           [0015]      FIG. 4  is a cross-sectional view of the ankle support brace of  FIG. 1 , taken along line  4 - 4  of  FIG. 1 . 
           [0016]      FIG. 5  is an exploded view of the ankle support brace of  FIG. 1 , showing the inner layer situated on a mold (shown in phantom) and two structural components. 
           [0017]      FIG. 6  is a perspective view of the ankle support brace of  FIG. 5 , in a subsequent process step showing the key structural components on the inner layer and the applied outer layer. 
           [0018]      FIG. 7  is a block diagram of an embodiment of a process for making an ankle support brace according to the disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    Embodiments of the disclosure relate to an ankle support brace (ASB) and methods of making the orthosis. The ASB is arranged to provide varus and valgus control and stabilize the talus (subtalar and mid-tarsal joints). The ASB of the disclosure helps protect against ankle weakness and/or instability of the ankle-foot structure. 
         [0020]    An embodiment of an ankle support brace  10  according to the disclosure is described with reference to  FIGS. 1 ,  3  and  4 . The brace can be used in combination with a standard shoe (shown in phantom in  FIG. 3 ). The brace is designed to be worn over a sock and inside the shoe without the need to increase the shoe size to accommodate the brace. The brace is in the general shape of a stirrup design without the heel portion of the boot and without the portion that would be forward of the mid-tarsal joint. 
         [0021]    Referring to  FIGS. 1 ,  3  and  4 , the ankle support brace  10  comprises a stirrup-shaped brace body  12  having a medial side portion  14 , a lateral side portion  16 , a medial front edge  18  of the medial side portion  14 , a lateral front edge  20  of the lateral side portion  16 , a sole portion  22 , an arch portion  24 , a heel opening edge  26  (forming a heel opening), and a back portion  28  extending from the heel opening edge  26 , forming a heel opening, to an upper calf portion  30 . The sole portion  22  is in a plane at least partially horizontal to the medial and lateral side portions  14 ,  16  of the brace body  12 . As can be seen, at least a portion of the sole portion  22  is at least partially perpendicular to the medial and lateral side portions  14 ,  16  of the brace body  12 . The ankle support brace  10  further includes a closure mechanism  32  to tighten and secure the orthosis to the foot.  FIGS. 1 and 3  are lateral and medial side views, respectively, of the ankle support brace  10 . 
         [0022]    As illustrated, the brace body  12  comprises a laminated structure of at least three material layers including an inner layer  34 , a polyolefin elastomeric outer layer  36 , and the rigid or semi-rigid key structural components as an intermediate layer  38  between the inner and outer layers  32 ,  34 . 
         [0023]    The inner layer  34  is composed of a closed cell polyethylene (PE) foam, which, in embodiments, is at least 1.5 mm thick, preferably at least 3.0 mm thick, up to 4.5 mm thick. Closed cell PE foams are commercially available, for example, under the tradenames Volara® from Sekisui Voltek, LLC (Lawrence, Mass.), and Aliplast from AliMed, Inc. (Dedham, Mass.). Sheets of closed cell polyethylene foam are commercially available. 
         [0024]    The outer layer  36  is composed of a rigid or semi-rigid thermoplastic material, preferably a polyolefin elastomeric material having thermoforming capabilities. In embodiments, the outer layer  36  is at least 2.0 mm thick, preferably at least 3.0 mm thick, up to 5.0 mm thick. In an embodiment, the polyolefin elastomeric material is an ethylene-butene copolymer or an ethylene-octene copolymer having a melt index range at 190° C. of less than 0.5 to 30 g/10 min (measured according to ASTM D 1238), a density of 0.857 to 0.910 g/cm 3  (measured according to ASTM D 792), a melting range of 36° C. to 104° C., a Shore A Hardness of 56 to 96 (ASTM D 2240), and a flexural modulus from 3 to 110 MPa (measured according to ASTM D 790). In another embodiment, the polyolefin elastomeric material is an ethylene-butene copolymer having a density of 0.885 g/cm 3  (measured according to ASTM D 792), a melt index of 1.0-2.5 g/10 min (2.16 kg @ 190° C. measured by ASTM D 1238), a Mooney Viscosity of 13 (ML 1+4 @121° C., measured according to ASTM 1646), a Shore A durometer hardness of 80-84 (measured according to ASTM 2240) and an ultimate tensile strength of 9.3-11.2 MPa (508 mm/min measured according to ASTM D 638). Polyolefin elastomers are well known and commercially available, for example, ENGAGE® ethylene/α-olefin copolymers available from The Dow Chemical Company. 
         [0025]    The ankle support brace  10  further includes an intermediate layer  38  defined by the key structural components and composed of a thermoplastic, polyolefin elastomeric material that is preferably at least 1.5 mm thick, preferably at least 3.0 mm thick, up to 4.5 mm thick. The key structural thermoplastic components are laminated (or inset) into the orthosis to provide support in target areas without reducing the flexibility of the brace body  12  in other areas. The intermediate layer  38  for the key structural components is preferably stiffer than the thermoplastic material used for the outer layer  36  of the brace body  12 . Nonlimiting examples of suitable thermoplastic polyolefin elastomers include polypropylene, polyethylene and modified polyethylene (MPE), which are commercially available from a number of sources. 
         [0026]    As shown in  FIG. 1 , a first key structural component is configured as a medial stirrup-type reinforcement strip  40  in one continuous strip with a first end  42   a  positioned below the proximal edge  44  of the brace body  12  on the medial side portion  14 , preferably at a distance (d) of about one-fifth (or 20%) of the total height (h) of the brace body from the proximal edge  44 . The reinforcement strip  40  extends to under the sole portion  22  at the arch portion  24  (at about mid-foot), and continues up the lateral side portion  16  with the second end  42   b  positioned below the proximal edge  44  of the brace body  12 , preferably at a distance (d) of about one-fifth (or 20%) of the total height (h) of the brace body  12  from the proximal edge  44 . 
         [0027]    In addition, a second key structural component is configured as a proximal reinforcement strip  46  positioned just below the proximal edge  44  of the brace body  12 , with a first end  48   a  positioned on the medial side portion  14  and extending around the posterior side portion  50  with a second end  48   b  positioned on the lateral side portion  16  of the brace body  12 . 
         [0028]    The first key structural component ( 40 ) (stirrup reinforcement strip  40 ) stabilizes the talus and provides varus and valgus control. The second key structural component (proximal reinforcement strip  46 ) provides additional circumferential rigidity and an attachment point for closure mechanisms. When the ankle support brace  10  is fastened on the foot, the first and second key structural components work in conjunction with each other to provide varus and valgus control. 
         [0029]    The closure mechanism  32  may include laces with a series of holes, eyelets, loops or hooks, Velcro® strips (available from Velcro USA, Inc.), elastic closures, cinched straps, zippers, snaps, buttons, hooks, clasps or other suitable fastener. In embodiments, when the closure mechanism  32  is engaged, the medial front edge  18  and the lateral front edge  20  of the brace body overlap, as shown in  FIG. 4 , such that the brace body does not require a separate tongue element. The overlap can be from 0.125 inches to 1.5 inches (0.32 cm to 3.8 cm), for example, 0.25 inch to 1.0 inch (0.64 cm to 2.5 cm). 
         [0030]    As illustrated in  FIG. 1 , in an embodiment, the closure mechanism  32  is in the form of a lace  52  that cooperates with two or more lace loops  54   a  positioned on the stirrup reinforcement strip  40  at the proximal section  62   b  (which would typically reside outside the shoe) of the brace body  12  to engage the lace  52  and tighten and secure the ankle support brace  10  onto the subject&#39;s foot. Because distal section  62   a  (or the region that would typically reside inside the shoe) is cut off so as to be toe-less and footless forward of the metatarsals, the distal section  62   a  does not include any closure mechanisms. In further embodiments, metallic or non-metallic “boot hook” style hardware can be installed in the stirrup-type reinforcement strip  40  to engage with the lace  52 . 
         [0031]    As shown in  FIG. 3 , the stirrup-like shape of the ASB  10  results in reduced material in the shoe compared to conventional boot-style braces. The reduced material in the shoe improves wearer mobility, particularly during athletic activity. The first key structural component ( 40 ) (stirrup reinforcement strip  40 ) and second key structural component (proximal reinforcement strip  46  provide support, stabilize the talus and provide varus and valgus control, and the overall design of the ASB  10  provides an enhanced element of control around the Achilles. As a result, the ASB  10  provides a balance of support and protection without hindering mobility. 
         [0032]    In another embodiment shown in  FIG. 2 , the closure mechanism  32 ′ is a hook and loop fastening mechanism in the form of an attachment strap  56 ′ as a first Velcro part with a one end secured to the proximal reinforcement strip  46 ′ and the stirrup reinforcement strip  40 ′ on the lateral side portion  16 ′ of the brace body  12 ′, and a loop element  60 ′ secured′ to proximal reinforcement strip  46 ′ and the stirrup reinforcement strip  40 ′ on the medial side portion  14 ′. The second end of the attachment strap  56 ′ is inserted through the loop of the loop element  60 ′, pulled back and attached to a cooperating second Velcro part  58 ′ to tighten the ankle support brace  10 ′ onto the person&#39;s foot and ankle. 
         [0033]    In some embodiments, the brace body  12  further includes an interface layer (not shown) that is applied over the foam inner layer  34  to enhance and provide a soft interface with the subject&#39;s foot. The interface layer can be, for example, a synthetic leather-like material (e.g., Clarino® artificial leather), a synthetic elastic fabric (e.g., Lycra® material), or other soft material. 
         [0034]    Optionally, a layer of a synthetic leather-like material (e.g., Clarino® artificial leather) or a synthetic elastic fabric (e.g., Lycra® material) can be applied over the surface of the foam inner layer, or a pre-laminated polyethylene foam with a bonded synthetic layer, to provide an interior interface with the foot to enhance the texture of the soft interface. 
       Method of Manufacture 
       [0035]      FIG. 7  provides a process flow diagram of a method of manufacture of an ankle support brace according to the disclosure. 
         [0036]    In first steps A and B, a mold  64  (e.g., plaster, wax, metal, wood, epoxy molds) of a patient&#39;s lower extremity is provided, as shown in phantom in  FIG. 5 . The mold  64  may be created from a 3D image or negative cast of the patient&#39;s extremity. Alternatively, instead of a mold being made from a patient&#39;s scan or cast, the mold may correspond to a pre-fabricated size. Thus, a patient may choose a pre-fabricated standard size that most closely fits their foot size. The correct size is determined by measuring the instep of a patient by placing a flexible tape around the instep and heel with the ankle at 90 degrees. The measurement and patient&#39;s shoe size are used to determine the best pre-fabricated size on a sizing chart. 
         [0037]    In a typical fabrication approach, the mold  64  to be used for the device being fabricated is mounted in a horizontal, tubular vacuum fixture. In a step C, a closed cell polyethylene foam lining material (for inner layer  34 ) is heated in sheet form and draped over the mold, from the posterior around to the anterior, thus establishing a straight seam from the toe through the instep and up past the proximal edge of the mold, thus enabling a seal around the tubular vacuum fixture. Vacuum is applied, creating an intimate capture by the closed cell polyethylene lining material  34  of the mold  64 , as shown in  FIG. 5 . 
         [0038]    An alternate method incorporates a slightly altered mold geometry, designed to accommodate mounting on a vacuum table, where the closed cell polyethylene foam lining material is mounted in a frame, heated, and brought down over the mounted mold. The closed cell polyethylene foam lining material seals against the table which is connected to a similar vacuum source, thus creating a similar seam and intimate capture of the mounted mold by the closed cell polyethylene lining material. 
         [0039]    In a step D, after the foam liner (inner layer  34 ) has cooled sufficiently, strategic areas of the closed cell polyethylene liner are cut away from the mold  64  to expose the anterior foot area  66 , the proximal surface  68  of the mold  64 , and an anterior strip  70  approximately 1.25-inches (3.2 cm) wide extending from the anterior foot area  66  to approximately ½-inch (1.3 cm) from the proximal edge  44 . The anterior portion of the foam liner is cut away by following a trim line that begins on the medial side at a point that bisects the mid-tarsal joint and continues to the lateral side to the bisection of the base of the fifth metatarsal shaft. The material is removed anterior of this trim line such that the resulting brace contains no foot portion forward of the metatarsals. The posterior portion of the boot is cut away by following a trim line from the plantar surface at the calcaneal shelf to a point just proximal the talus. The boot material is removed posterior of this trim line such that the resulting brace contains no heel portion. These cut outs provide for sufficient vacuum for subsequent thermoforming steps as well as reducing bulk in the instep region where the finished device will overlap. 
         [0040]    In a step E, the key structural thermoplastic components are manufactured using predetermined, standardized sizing and can be stamped out of sheet material using a clicker die press process or similar. The appropriate size of the horizontal/proximal key structural thermoplastic component (proximal reinforcement strip  46 ) can be determined by taking a measurement from one anterior/posterior midline to the other anterior/posterior midline, at the location to which the component  46  will be mounted as per the fabrication standards established. The appropriate size of the key structural thermoplastic component, the medial stirrup-type reinforcement strip  40 , can be determined by placing a thin, flexible, transparent template identical in dimension to the key thermoplastic component on the mold being used for fabrication. The template that fits the fabrication standards established corresponds to the size of the key structural thermoplastic component  40  used for fabrication. 
         [0041]    In a step F, both key structural reinforcement components  40 ,  46  are heated to approximately 225° F. or until they become moldable. The actual temperature required can vary as a function of the thermoplastic material being used for the key structural thermoplastic components. After heating, the components  40 ,  46  are removed from the oven and, as illustrated in  FIGS. 5 and 6 , placed, nearly simultaneously, onto the closed cell polyethylene liner material (inner layer  34 ), in locations outlined by the fabrication standard. A heat resistant plastic or silicone bag is placed over the entire mold assembly and sealed to the vacuum pipe, at which point vacuum is applied, thus creating an intimate relationship between the bag, the thermoplastic key structural reinforcement components  40 ,  46  and the mold  64  and closed cell polyethylene liner  34  assembly. Vacuum is applied until the thermoplastic components  40 ,  46  have cooled to a non-moldable temperature, at which point the vacuum bag is removed from the assembly. During this process, the key structural reinforcement thermoplastic components  40 ,  46  will have bonded permanently to the closed cell polyethylene lining material  34 . The bases of the lace loops  54   a  are placed on the proximal section  62   b  (which would typically reside outside the shoe) of the medial stirrup-type reinforcement strip  40 . Alternatively, Velcro fasteners can be placed on the exterior of the brace body  12  on the proximal section  62   b . In an embodiment, the bases of the lace loops  54   a  are heat welded or ultrasonic welded together. 
         [0042]    In a next step G, the polyolefin elastomeric material to form the outer layer  36  is thermoformed over the assembly, typically using a method nearly identical to the process used for the closed cell polyethylene lining material  34 . During thermoforming, the polyolefin elastomeric material outer layer  36  is heated to a temperature from 225° F. to 250° F. and placed over the mold  64 , the key structural thermoplastic components  40 ,  46 , and the lace loops  54   a  to produce the brace body  12 . In an embodiment, after the polyolefin elastomeric material for the outer layer  36  is draped over the mold  64  from the posterior around to the anterior thus establishing a straight seam from the region of the toe  66 , through the instep (sole portion  22 ) and up past the proximal edge  68  of the mold  64 , a vacuum is used to seal the polyolefin elastomeric material outer layer  36  over the mold, the key structural thermoplastic components  40 ,  46 , and the lace loops  54   a . The vacuum can be maintained until the polyolefin elastomeric material outer layer  36  returns to room temperature. The mold  64  is then removed once the polyolefin elastomeric material outer layer  36  has cooled to room temperature to produce the ankle support brace  10 . 
         [0043]    In a next step H, finishing and trimming of the plastic layers of the brace body is performed. 
         [0044]    In a next step I, a cut is made in the polyolefin elastomeric material outer layer  36  across the width of the distal base of a lace loop  54   a  just dorsal to the stirrup-type reinforcement strip  40 , from which the lace loop  54   a  is pulled through to partially expose the lace loop  54   a  for future lacing. Fasteners  72  are added to further secure the base of the lace loops  54   a , outer layer  36 , the stirrup-type reinforcement strip  40 , and the foam inner layer  34  together. Alternatively, metallic or non-metallic “boot hook” style hardware can be installed in the proximal section  62   b  of the medial stirrup-type reinforcement strip  40  (which would typically reside outside the shoe) in place of lace loops. 
         [0045]    In an embodiment, the height of the anterior and dorsal surfaces of the mold are such that the medial front edge  18  and the lateral front edge  20  may be overlapped when the ankle support brace is tightened by the closing mechanism  32 , as illustrated in  FIGS. 1 and 2 . 
         [0046]    Additionally, in an embodiment, the closed cell polyethylene lining material (inner layer  34 ), the key structural reinforcement components  40 ,  46 , and the base of the lace loops  54   a  are laminated in the brace body  12  such that a layer of a synthetic fabric (e.g., Clarino or Lycra) is first placed on the mold, or use a pre-laminated foam with a bonded synthetic layer, followed by the placement of the polyethylene foam inner lining material ( 34 ), the key structural reinforcement components  40 ,  46 , and the base of the lace loops  54   a . Then the outer layer  36  of polyolefin elastomeric material is placed over the reinforcement strips  40 ,  46  and lace loops  54   a  thereby encapsulating the key structural reinforcement components and lace loops in the brace body. Other closure mechanisms besides lace loops and laces are contemplated and considered within the scope of the disclosure. 
         [0047]    It is specifically intended that the present disclosure not be limited to the embodiments and illustrations contained herein, but include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claim.