Abstract:
An elongate flexible strap is adapted to be wrapped about a wearer&#39;s leg and pelvic region. The strap applies a torque to the leg, rotating the leg into a desired degree of external rotation. In a leg having an improperly aligned patella, it is believed that the external rotation improves lower extremity mechanics by aligning the patella within the trochlear groove.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to orthopedic devices for improving lower-extremity mechanics. 
     2. Description of the Related Art 
     Many people suffer from abnormal motions of the patella. There are several basic types of abnormalities that may occur with the patella: it may dislocate (slip out of place), sublux (partially slip out of place), fracture, develop degenerative arthritis, or develop a tracking problem. A tracking problem describes a patella that stays in place in front of the knee, but no longer remains centered in the front part of the femur known as the trochlear groove. 
     When tracking problems occur, the kneecap develops an abnormal set of biomechanics that results in abnormally increased pressure on the underside of the patella (patellar articular surface). The pain that results from this condition has a variety of different names, but all of these diagnoses refer to a biomechanical abnormality of the joint space between the patella and the trochlear groove of the femur. Normally, the patella sits centered in the groove. 
     One conventional treatment for patellar tracking problems comprises fitting the sufferer with an external brace. Many of these braces apply force directly to the patella in order to maintain it within the trochlear groove and to force it to follow the proper tracking path. For example, U.S. Pat. No. 4,296,744 to Palumbo discloses a dynamic patellar brace for both diagnosis and treatment of patellar subluxation. The brace includes a patellar bracing pad adapted to be positioned laterally with respect to the patella. The pad applies medially-directed pressure to the patella to help prevent subluxation. 
     SUMMARY OF THE INVENTION 
     The preferred embodiments of the present device and method for externally rotating the femur have several features, no single one of which is solely responsible for their desirable attributes. Without limiting the scope of this device and method as expressed by the claims that follow, their more prominent features will now be discussed briefly. After considering this discussion, and particularly after reading the section entitled “Detailed Description of the Preferred Embodiments,” one will understand how the features of the preferred embodiments provide advantages, which include comfort, light weight, an unobtrusive appearance, and the ability to treat the causes of lower extremity dysfunction, rather than the symptoms. 
     Many people suffer from abnormal motions of the femur. These abnormal motions may be caused by hip muscle weakness, bony deformities of the hip (such as excessive anteversion), or a lack of lower extremity motor control. It is believed that these abnormal motions of the femur can sometimes cause a misalignment of the patella within the trochlear groove and/or patellar tracking problems, with subsequent patellofemoral joint pain. Therefore, one aspect of the present device and method for externally rotating the femur includes the realization that when correcting lower extremity mechanics, it is preferable to focus on the cause of any abnormal motion(s) (for example, abnormal motions of the femur), rather than to focus on the symptoms of the abnormal motion(s) (for example, misalignment of the patella). Accordingly, one embodiment of the present device and method applies a torque to the femur in order to externally rotate the femur. With respect to a leg having a patella that is not properly aligned within the trochlear groove, it is believed that the externally rotated femur induces a proper alignment by moving the femur underneath the patella. 
     One embodiment of the present device and method for externally rotating the femur comprises a device for applying a torque to a wearer&#39;s leg. The torque moves the leg into external rotation to improve lower-extremity mechanics and align the patella with the trochlear groove. The device comprises an elongate flexible strap including a first portion, a second portion, a third portion, a fourth portion and a fifth portion. The first portion is adapted to engage the leg below the knee. The second portion is adapted to engage the leg along a medial side of the knee. The third portion is adapted to engage the leg above the knee. The fourth portion is adapted to extend along the thigh from a lower medial side thereof to an upper lateral side thereof. The fifth portion is adapted to engage the wearer&#39;s pelvic region. 
     Another embodiment of the present device and method for externally rotating the femur comprises a device for applying a torque to a wearer&#39;s leg. The torque moves the leg into external rotation to improve lower-extremity mechanics and align the patella with the trochlear groove. The device comprises an elongate flexible strap including a relatively long first portion. A second portion extends from an end of the first portion in a direction substantially perpendicular to the first portion. A third portion extends from an end of the second portion opposite the first portion in a direction substantially perpendicular to the second portion, substantially parallel to the first portion, and in a common direction with the first portion. 
     Another embodiment of the present device and method for externally rotating the femur comprises a device for applying a torque to a wearer&#39;s leg. The device comprises a first portion adapted to engage the leg in a region of the knee, a second portion adapted to extend around the thigh along a substantially helical path, and a third portion adapted to engage the wearer&#39;s pelvic region. 
     Another embodiment of the present device and method for externally rotating the femur comprises a method of moving a wearer&#39;s leg into external rotation. The method comprises the steps of securing to the leg in a region of the knee a first portion of a torquing device, applying a torque to the first portion by pulling a second portion of the torquing device in an upward and lateral direction, and securing a third portion of the device about the wearer&#39;s pelvic region to thereby maintain tension in the second portion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The preferred embodiments of the present device and method for externally rotating the femur, illustrating its features, will now be discussed in detail. These embodiments depict the novel and non-obvious device and method shown in the accompanying drawings, which are for illustrative purposes only. These drawings include the following figures, in which like numerals indicate like parts: 
         FIG. 1  is a top plan view of one embodiment of the present device for externally rotating the femur; 
         FIG. 2  is a bottom plan view of the device of  FIG. 1 ; 
         FIG. 3  is a detail bottom perspective view of the device of  FIG. 1 ; 
         FIG. 4  is a front elevational view of a wearer&#39;s leg and the device of  FIG. 1 , illustrating one step of applying the device to the leg; 
         FIG. 5  is a front elevational view of the leg and the device of  FIG. 4 , illustrating another step of applying the device to the leg; 
         FIG. 6  is a front elevational view of the leg and the device of  FIG. 4 , illustrating another step of applying the device to the leg; 
         FIG. 7  is a front elevational view of the leg and the device of  FIG. 4 , illustrating another step of applying the device to the leg; 
         FIG. 8  is a front elevational view of the leg and the device of  FIG. 4 , illustrating another step of applying the device to the leg; and 
         FIG. 9  is a front elevational view of the leg and the device of  FIG. 4 , illustrating the device applied to the leg and to the wearer&#39;s torso. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIGS. 1-3  illustrate one embodiment of the present device  20  for externally rotating the femur. In these figures, the device  20  has been laid flat for ease of reference. The illustrated device  20  is adapted for wear on a left leg. However, those of ordinary skill in the art will appreciate that a device  20  having a mirrored configuration would be adapted for wear on a right leg. In fact,  FIGS. 4-9  illustrate such a device having a mirrored configuration, and the steps for applying the device to a right leg. 
     The device  20  comprises a relatively thin, elongate strap  22  having a plurality of strap sections. In the flat configurations of  FIGS. 1 and 2 , the device  20  resembles a J. Thus, one section  24  of the strap  22  is substantially straight and is adapted to encircle the wearer&#39;s thigh and pelvis, as described in detail below. At one end, the thigh/pelvis strap section  24  adjoins a medial knee strap section  26  that extends substantially perpendicular to the thigh/pelvis strap section  24 . The medial knee strap section  26  extends away from the thigh/pelvis strap section  24  and adjoins a calf strap section  28  that extends substantially perpendicular to the medial knee strap section  26 , substantially parallel to the thigh/pelvis strap section  24 , and in substantially the same direction as the thigh/pelvis strap section  24 . 
     In  FIGS. 1 and 2 , the thigh/pelvis strap section  24  has been broken for ease of illustration. In one embodiment, this strap section is considerably longer than the remaining sections. For example, in one embodiment the thigh/pelvis strap section  24  is approximately 80 inches long, while the medial knee strap section  26  is approximately 10 inches long and the calf strap section  28  is approximately 18 inches long. Those of skill in the art will appreciate that the dimensions provided are merely one example, and should not be interpreted as limiting. 
     In the illustrated embodiment, the strap sections described above comprise a unitary piece of a flexible material. In some embodiments, the unitary flexible material may comprise several layers. For example, the strap  22  material may comprise a laminate of polyurethane foam and brushed nylon. In some embodiments, the strap  22  material may be durable, elastic, compressible and/or lightweight. Those of skill in the art will appreciate that the strap sections described above need not be constructed in a unitary fashion, and may be constructed separately and then secured together, for example by stitching. 
     With reference to  FIG. 1 , in the illustrated embodiment, a first surface, or outer surface  30 , of the strap  22  comprises a loop material that is adapted to receive a hook material for releasable engagement. This outer surface  30  may be constructed of brushed nylon. The outer surface  30  faces away from the wearer when the device  20  is worn as described below. A plurality of hook material sections may be secured to the strap  22 . For example, with reference to  FIG. 1 , an end of the thigh/pelvis strap section  24  opposite the medial knee strap section  26  may include a first patch  32  of hook material. A second patch  34  of hook material may be located at an end of the calf strap section  28  opposite the medial knee strap section  26 , and a third patch  36  of hook material may be located at the junction of the thigh/pelvis strap section  24  and the medial knee strap section  26 . 
     Each of the patches  32 ,  34 ,  36  may be releasably secured to the strap  22 , or each may be permanently secured to the strap  22 . For example, in  FIGS. 1 and 2  the first patch  32  is releasably secured to the strap  22 . The hook material on the first patch  32  engages the loop material on the outer surface  30  of the strap  22 . A portion of the first patch  32  extends beyond the end of the thigh/pelvis strap section  24 . This portion is adapted to be releasably secured to another portion of the strap  22  when the device  20  is applied to the wearer, as described below. The second patch  34  and third patch  46  are each permanently secured to the strap  22  with stitching. Those of ordinary skill in the art will appreciate that the patches may be secured to the strap  22  using alternative methods, such as snaps or buttons. Those of ordinary skill in the art will also appreciate that any of the patches may be permanently or releasably secured to the strap  22 . The illustrated configuration is merely one example. 
     With reference to  FIG. 2 , a second surface, or inner surface  38 , of the strap  22  comprises a relatively smooth material. The inner surface  38  faces the wearer&#39;s skin and/or clothing when the device  20  is worn as described below. Thus, the inner surface  38  may advantageously have a relatively high coefficient of static friction relative to human skin and most fabrics that people typically wear. The strap  22  is thus less prone to slip out of its intended position. In one embodiment, the inner surface  38  comprises polyurethane foam. However, those of ordinary skill in the art will appreciate that the inner surface  38  could be constructed of alternative materials, and that it need not necessarily have a high coefficient of static friction as described above. 
     With further reference to  FIG. 2 , a strip  40  of loop material is secured to the inner surface  38  of the strap  22  along the thigh/pelvis strap section  24 . The loop material strip  40  may be secured to the inner surface  38  with stitching or any other means. The loop material strip  40  is located near the end of the thigh/pelvis strap section  24  that adjoins the medial knee strap section  26 , and extends along approximately one-fifth of the length of the thigh/pelvis strap section  24 . Those of ordinary skill in the art will appreciate that the relative lengths of the thigh/pelvis strap section  24  and the loop material strip  40  may be varied. In one embodiment, the loop material strip  40  is approximately 16 inches long. However, those of ordinary skill in the art will appreciate that the loop material strip  40  may be any length. 
     With reference to  FIGS. 2 and 3 , a calf-encircling band  42  is secured to the strap  22  near the junction of the thigh/pelvis strap section  24  and the medial knee strap section  26 . The calf band  42  comprises a length of material sufficient to extend around at least a portion of the wearer&#39;s calf. The calf band  42  may be made from a flexible and elastic material. In one embodiment, the calf band  42  may be made of a composite of nylon, polyester and rubber. In the illustrated embodiment, opposite ends of the band  42  are secured to the strap  22  with stitching. Those of ordinary skill in the art will appreciate that the band may be secured to the strap  22  using alternative means, such as releasable fasteners. 
       FIGS. 4-9  illustrate one method of externally rotating the femur using the present device  20 . With reference to  FIG. 4 , the wearer begins by passing his or her foot through the calf band  42  and sliding the calf band  42  upward along the lower leg until the calf band  42  is positioned just below the knee  44 . The medial knee strap section  26  should extend along the medial side of the wearer&#39;s leg above and below the knee. The calf strap section  28  should be located below the knee, and at least part of the thigh/pelvis strap section  24  should be located above the knee. 
     With reference to  FIG. 5 , the wearer next wraps the calf strap section  28  around his or her calf, over the calf band  42 , and secures the second patch  34  of hook material to the outer surface  30  of the calf strap section  28 . The wearer preferably applies sufficient tension to the calf strap section  28  to prevent migration while maintaining comfort for the wearer and not impeding circulation within the leg. With reference to  FIG. 6 , the wearer next wraps the thigh/pelvis strap section  24  across the anterior portion of his or her thigh just above the knee  44 . The wearer continues wrapping the thigh/pelvis strap section  24  around the posterior portion of his or her thigh and back to the anterior portion. Using one hand, the wearer positions the junction of the medial knee strap section  26  and the thigh/pelvis strap section  24  so that it is located on the medial side of his or her leg above the knee. Using his or her other hand, the wearer then wraps the thigh/pelvis strap section  24  over the junction so that the loop material strip on the inner surface  38  of the strap  22  engages the third patch  36  of hook material on the outer surface  30  of the strap  22 . As shown in  FIG. 7 , in one embodiment the third patch  36   a  may be removable and repositionable with respect to the strap  22 . In this embodiment the wearer may reposition the third patch  36   a  for optimal engagement with the loop material strip  40 . The wearer preferably applies tension to the thigh/pelvis strap section  24  before engaging the hook material to the loop material so that the thigh/pelvis strap  22  does not slip relative to the thigh. However, the tension should be light enough to maintain comfort for the wearer and not impede circulation within the leg. Furthermore, those of ordinary skill in the art will appreciate that neither the third patch  36 ,  36   a  nor the loop material strip  40  is essential to the proper functioning of the present device  20 . 
     With reference to  FIG. 8 , the wearer next grasps the thigh/pelvis strap section  24  with his or her right hand (if the device  20  is being applied to the right leg), or with his or her left hand (if the device  20  is being applied to the left leg). Positioning his or her foot such that the heel rests on the floor and the toes are pointed slightly upward, the wearer pulls the thigh/pelvis strap section  24  upward and laterally. The pulling force applies a torque to the leg that moves the leg into external rotation. In one embodiment, the amount of external rotation may be within the range of 5° to 25° of external rotation, and may be within the range of 10° to 20° of external rotation in another embodiment. Finally, with reference to  FIG. 9 , the wearer wraps the thigh/pelvis strap section  24  diagonally upward and around his or her thigh following a substantially helical path, then around the waist, and secures the first patch of hook material to the outer surface  30  of the strap  22 . In one embodiment, the strap  22  is located over the pelvis and greater trochanter, but below the iliac crest. However, those of ordinary skill in the art will appreciate that the strap  22  could be located higher or lower. The wearer preferably applies sufficient tension to the thigh/pelvis strap section  24  to maintain external rotation of the femur while maintaining comfort for the wearer and not impeding circulation. 
     With the device  20  applied as shown in  FIG. 9 , the wearer&#39;s femur is external rotated while the patella remains stationary. Thus, the femur moves relative to the patella so that the patella becomes properly aligned with the trochlear groove. The device  20  is advantageously comfortable to wear, at least in part because of its light weight and flexibility. Further, the device comprises a flat strap with no rigid or protruding portions. Thus, it has an unobtrusive appearance that is easily hidden beneath clothing. The easy disguisability of the device means that a wearer need not feel any embarrassment over his or her need to wear an orthopedic appliance in public. The device  20  also provides effective treatment of patellofemoral misalignment, because it treats the cause of such misalignment (abnormal motions of the femur and tibia), rather than the symptoms. 
     SCOPE OF THE INVENTION 
     The above presents a description of the best mode contemplated for carrying out the present device and method for externally rotating the femur, and of the manner and process of making and using them, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains to make and use this device and to practice this method. This device and this method are, however, susceptible to modifications and alternate constructions from that discussed above that are fully equivalent. Consequently, this device and this method are not limited to the particular embodiments disclosed. On the contrary, this device and this method each cover all modifications and alternate constructions coming within the spirit and scope of the device and method as generally expressed by the following claims, which particularly point out and distinctly claim the subject matter of the device and method.