Abstract:
A knee brace for use by athletes or others requiring protection and support of the knee. The knee brace protects against abnormal motions of the knee, and provides direct and indirect patella stabilization. A base comprised of elastic material is configured to closely fit around portions of the knee and adjacent leg portions. Direct patella support is provided by upper crossed straps that are permanently fastened to the base and cross the front of the leg above the knee, or by lower crossed straps that are permanently fastened to the base and cross the front of the leg below the knee, or by both upper and lower crossed straps. Additional direct patella support may be provided by a patella opening. One or more generally upright lateral pockets containing semi-rigid stays may also be provided on the sides of the base for lateral support. A popliteal opening may be provided to reduce the possibility of chafing at the rear of the knee.

Description:
FIELD OF THE INVENTION 
     This invention relates generally to the field of articles worn by persons to reduce the likelihood, severity, or exacerbation of injury to the body, and more specifically to the field of braces worn on the knee. 
     BACKGROUND OF THE INVENTION 
     Flexible knee braces are used by athletes and other persons engaged in vigorous physical activity to protect the knee from injury and to avoid exacerbation of existing injury. The knee is one of the most heavily used joints of the body, as it is used in any activity that involves walking or running. The knee is also a common subject of injury, due to the relatively high levels of stress it must bear. During normal ambulation, in occupations involving physical labor, and especially during strenuous sports, the knee can undergo abnormal motions as a result of quick changes in direction, fatigue, uneven surfaces, or impacts. These abnormal motions can cause sprains or more serious injuries, including dislocation, stretching, or tearing of the tissues that make up the knee. 
     Several different types of abnormal motion can cause injury to the knee. First, hyperextension of the knee joint can occur, wherein the knee flexes in its normal front to back fashion but beyond its normal range of motion. A second type of abnormal motion is axial rotation, wherein the lower leg is twisted rotationally relative to the thigh about the knee joint. A third type of abnormal motion is lateral flexure of the lower leg relative to the thigh, wherein the knee joint flexes from side to side instead of the normal front to back motion. In addition, abnormal motion of the patella (kneecap) can result in injuries such as chondromalacia patella, which is a softening or degeneration of the undersurface of the patella, and dislocation of the patella, also known as subluxation of the patella. 
     Devices to protect the knee against abnormal motions have been used for many years, in a variety of specific embodiments which vary in their abilities to protect against the different types of abnormal motions. Besides protecting the knee against abnormal motions, the devices sometimes provide additional benefits such as insulating the knee to keep it warm, protecting the knee against impact, or compressing the knee to reduce discomfort. However, the protections afforded by these devices against abnormal motion are often accompanied by a reduction in range or ease of normal motion. These devices can also have other undesirable aspects such as added weight on the leg, potential for self-injury or injury to others caused by rigid components, difficulty of application and removal, cost, appearance, and irritation or chafing of the skin. 
     For these reasons, there has long been motivation to find an improved knee brace which can protect the knee from abnormal motions without affecting the range or ease of normal motion, while avoiding the undesirable aspects of prior art devices. 
     SUMMARY OF THE INVENTION 
     A knee brace according to the present invention includes crossed support straps which are permanently fixed to the base of the brace. This eliminates any need to fasten the crossed support straps, thereby avoiding the possibility of error during application of the brace, and helps to ensure the proper fit at all times of the crossed support straps. Further, as the knee moves between flexion and extension positions, the straps self-adjust to the position of the knee. 
     A knee brace according to the invention preferably includes both upper and lower crossed support straps, but this is not necessary. A knee brace according to the invention may include upper crossed straps without lower crossed support straps, or such a knee brace may include lower crossed straps without upper crossed support straps. The midpoints of the crossed straps may be fastened to each other, or to the base, although this is not required. 
     According to another aspect of the invention, the knee brace may include one or more upright support members fastened to either or both sides of the base, although this is not required. The upright support members may be a resilient stay member, or a hinge, or other upright support members known in the art. The upright support member may be removable. 
     According to another aspect of the invention, the knee brace may include a diamond shaped or round opening around the patella (kneecap), although other shapes could be used. A preferred embodiment includes a diamond-shaped opening which may conform to the shape of the patella particularly well. 
     According to another aspect of the invention, the knee brace may include a circular opening over the popliteal area (the area at the rear of the knee). Such a popliteal opening can decrease the chance of irritation of the skin in that area. 
     A knee brace according to the invention can protect against all forms of abnormal knee motion and provide patella support, while avoiding undue restriction of movement or bunching. It can provide therapeutic warming without undue moisture buildup. It is easy to adjust, fasten, and remove, and it can be used by a wide range of people with a variety of knee problems and knee sizes. 
     Further objects, features, and advantages of the invention will be apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a front perspective view of a knee brace according to the invention fitted on the leg of a person; 
         FIG. 2  is a side view of a knee brace according to the invention fitted on the leg of a person; 
         FIG. 3  is a front view of a knee brace according to the invention laid flat; 
         FIG. 4  is a rear view of a knee brace according to the invention laid flat; 
         FIG. 5  is a side view of an exemplary resilient stay member; 
         FIG. 6  is a front view of an exemplary resilient stay member; and 
         FIG. 7  is a cross-sectional view of the knee brace of  FIG. 1  taken along the line  7 - 7  thereof. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the drawings,  FIGS. 1-4  show a preferred embodiment of a knee brace according to the invention indicated generally at  20 . As normally worn by a person, the upper leg  21  extends from an opening at the top of the knee brace  20 , and the lower leg  22  extends from an opening at the bottom of the knee brace  20 . 
     The knee brace  20  includes a base  28 , having a first side  29  and a second side  30 , which is preferably formed as a reclosable sleeve made from a sheet of elastic material which provides generalized support and compression to the knee area, along with therapeutic warming, but other materials may be used. The base  28  may also be formed, for example, of a tubular elastic sleeve shaped to fit snugly about the knee and adjacent leg portions. 
     The base  28  may include a patella opening  31  which generally matches the size of the patella, such that the patella (kneecap)  23  of the wearer extends from the patella opening  31  when the brace  20  is worn, although this is not necessary. The patella opening  31  is preferably diamond-shaped, but this is not necessary and other shapes may be used. In addition to providing direct patella stabilization, the patella opening  31  may help to locate the brace  20  with respect to the patella  23  during application of the brace  20 . 
     As best shown in  FIGS. 3 and 4 , the first side  29  and second side  30  of the base  28  are preferably each formed to terminate in upper fastening tabs  32  and lower fastening tabs  33 . When the base  28  of the knee brace  20  is wrapped about the leg of a person, the pair of upper fastening tabs  32  overlap at the rear of the leg where they may be detachably attached together in order to fasten the knee brace  20  about the upper leg  21  of the wearer. Similarly, the pair of lower fastening tabs  33  overlap at the rear of the leg where they may be detachably attached together in order to fasten the knee brace  20  about the lower leg  22  of the wearer. 
     A gap  34  may be provided between the upper fastening tabs  32  and the lower fastening tabs  33 , so that when the knee brace  20  is fitted upon the leg the gaps on each side form a popliteal opening  35  at the rear of the knee, to avoid chafing, provide ventilation, and avoid bunching or undue restriction of movement, although this is not required. 
     In a preferred embodiment, each pair of upper fastening tabs  32  and lower fastening tabs  33  may be detachably attached together, preferably using hook and loop material of the type which adheres when pressed together. Areas of hook type fastening material  36  may be fastened, for example by stitches  37 , onto one of the upper fastening tabs  32  and one of lower fastening tabs  33 . The other upper fastening tab  32  and the other lower fastening tab  33  (which do not bear areas of hook type fastening material  36 ) may be partially or entirely covered in loop type fastener material  38 . 
     When the base  28  of the knee brace  20  is wrapped about the leg with the areas of hook type fastening material  36  on one upper fastening tab  32  and one lower fastening tab  33  overlapping and engaging the loop type fastening material  38  on the other upper fastening tab  32  and the other lower fastening tab  33 , each pair of upper fastening tabs  32  and lower fastening tabs  33  may be detachably attached by pressing them together, thereby fastening the brace about the leg of the wearer. 
     As shown in  FIG. 2  and as shown in cross-section in  FIG. 7 , one or more upright support members  45  may be provided on the first side  29  or second side  30  or on both sides of the base of the knee brace, to provide support and protect the knee against abnormal motions, although this is not required. In a preferred embodiment, the upright support members  45  may be formed, for example, by placing a resilient stay member  46  in an elongated side pocket  47 . As shown in  FIGS. 5 and 6 , the resilient stay members  46  are preferably comprised of a flattened spiral core of stainless steel or other flexible material of conventional construction commonly used in various types of braces. 
     The elongate side pocket  47  may be formed, for example, between vertical sewn seams  48  that fix a side pocket cover strip  49  to the base  28 . The side pocket cover strip  49  may be made of the same elastic sheet material as the base  28  of the knee brace  20 , although this is not necessary. Edge binding  50  may be fastened to the edges of the side pocket cover strips  49 , for example using stitches  48 , although this is not necessary. 
     As shown in  FIGS. 1-4 , a preferred embodiment of a knee brace according to the invention includes a first upper support strap  59  and a second upper support strap  60 , each upper support strap having an upper end  61 , a midpoint  62 , and a lower end  63 . The first upper support strap  59  and second upper support strap  60  are permanently fastened to the base  28  in a crossed fashion, by permanently fastening the upper end  61  of the first upper support strap  59  and the lower end  63  of the second upper support strap  60  to the first side  29  of the base and by permanently fastening the upper end  61  of the second upper support strap  60  and the lower end  63  of the first upper support strap  59  to the second side  30  of the base, preferably using the stitches  48  which secure the side pocket cover strips  49  to the base  28 . The midpoints  62  of the crossed first upper support strap  59  and second upper support strap  60  may also be permanently fastened together, or fastened to the base, preferably using stitches  64 . 
     As shown in  FIGS. 1-4 , a preferred embodiment of a knee brace according to the invention may also include a first lower support strap  69  and a second lower support strap  70 , each lower support strap having an upper end  71 , a midpoint  72 , and a lower end  73 . The first lower support strap  69  and second lower support strap  70  are preferably permanently fastened to the base  28  in a crossed fashion, by permanently fastening the upper end  71  of the first lower support strap  69  and the lower end  73  of the second lower support strap  70  to the first side  29  of the base and by permanently fastening the upper end  71  of the second lower support strap  70  and the lower end  73  of the first lower support strap  69  to the second side  30  of the base, preferably using the stitches  48  which secure the side pocket cover strips  49  to the base  28 . The midpoints  72  of the crossed first lower support strap  69  and second lower support strap  70  may also be permanently fastened together, or fastened to the base  28 , preferably using stitches  74 . 
     There are various possibilities with regard to alternative embodiments of a knee brace according to the invention. 
     Although in a preferred embodiment the knee brace  20  includes a base  28  which is formed as a reclosable sleeve made from a sheet of elastic material, this is not required. For example, the base  28  may also be formed of a tubular elastic sleeve shaped to fit snugly about the knee and adjacent leg portions. The base  28  does not need to include a patella opening  31 , and the patella opening  31 , if present, could have a variety of shapes, e.g. circular, square, rectangular, elliptical, diamond, trapezoidal, or any substantial equivalent. All such alternative embodiments will be referred to herein as a base. 
     Although in a preferred embodiment the first side  29  and second side  30  of the base each terminate in upper fastening tabs  32  and lower fastening tabs  33 , with a side gap  34  between the upper and lower fastening tabs, this is not required. For example, the first side  29 , or the second side  30 , or both sides of the base, or portions thereof, could be straight. 
     Although in a preferred embodiment the base is detachably fastened about the leg of the wearer using hook and loop material of the type which adheres when pressed together, this is not required. For example, other fasteners such as buttons, clasps, buckles, pins, zippers, straps, buttons or other substantial equivalents may be substituted for the hook and loop type fastener material. 
     Although in a preferred embodiment, various components are permanently fastened together using stitches, this is not required. For example, other means such as glue, thermal bonding, or other substantial equivalents could be used. 
     Although in a preferred embodiment, two upright support members  45  (shown in cross-section in  FIG. 7 ) are provided on the first side  29  and second side  30  of the base of the knee brace, this is not necessary, and the exact number, location, and construction of the upright support members  45  may vary. For example, there may be a single elongated side pocket  47  forming only one upright support member  45 , or there may be one or more elongated side pockets  47  on each side of the knee with a resilient stay  46  in each elongated side pocket  47 . The elongated side pockets  47  may be openable at one end to allow removal of the resilient stays  46 , so that the brace may be washed or so that different resilient stays  46  may be inserted to adjust the amount and type of support provided. The upright support members  45  may include mechanical hinges, plastic rods, metal rods, narrow strips of reinforcing sheet material, or other substantial equivalents, or a combination of these various alternatives. 
     As shown in  FIGS. 1-4 , a preferred embodiment of a knee brace according to the invention may include crossed first upper support strap  59  and second upper support strap  60  and crossed first lower support strap  69  and second lower support strap  70 , wherein the ends of each pair of crossed support straps are permanently fastened to the base, although other arrangements are possible. For example, there may be a pair of crossed upper support straps which are permanently fastened to the base, without a pair of crossed lower support straps which are permanently fastened to the base, or with lower support straps arranged in a different configuration. Similarly, there may be a pair of crossed lower support straps which are permanently fastened to the base, without a pair of crossed upper support straps which are permanently fastened to the base, or with upper support straps arranged in a different configuration. 
     It is understood that the invention is not confined to the embodiments set forth herein as illustrative, but embraces all such forms thereof that come within the scope of the following claims.