Abstract:
An improved AFO joint is described herein with improved stability and anti-rotational features. In particular, the AFO joint comprises a body portion with a medial beam for support and improved patient gait. Additionally, the AFO described herein comprises a tensioning member with high strength and a low profile for improved biomechanical effect.

Description:
BACKGROUND 
       [0001]    There are a number of pathologies that can lead to loss of function of the foot and ankle. A non-limiting list of pathologies include muscular dystrophy, multiple sclerosis, cerebral palsy and peripheral vascular disease. Often the biomechanical deficit will involve loss of the ability to bring the foot up (i.e. dorsiflexion). This situation is generically known as drop foot. 
         [0002]    One solution is the use of an orthosis, such as the articulated Ankle Foot Orthosis (“AFO”). This orthosis has an upper portion (calf section) connected to a lower portion (foot section) by a joint. The joint is internally or externally spring loaded so that it picks up the foot and/or prevents the foot from dropping. For a spastic patient, a range limiting joint design may be indicated. A range limiting joint limits the patient&#39;s ability to push the foot down (plantarflex) beyond a predetermined angle. The articulated design allows for better biomechanical movement of the foot. 
         [0003]    U.S. Pat. No. 5,826,304 describes a composite flexure unit for hingedly joining two relatively movable parts. The unit includes a flexure member comprising a low modulus of elasticity material. The flexure has two mounting portions and a middle connecting portion. The flexure is bendable for pivoting about a rotational axis passing through the middle portion. A load bearing element comprises a high modulus of elasticity material for providing longitudinal strength and stiffness, without significantly increasing flexion stiffness about the rotational axis. An improvement over the Carlson patent is known and marketed under the trade name Tamarak Variable Assist™ Joint, (available from Tamarack Habilitation Technologies, Inc, Blaine, Minn., USA) wherein an adjustable hinge is added to one of the mounting portions, to allow mounting the flexure unit at adjustable angles to a portion of the brace. 
         [0004]    U.S. Pat. No. 4,665,904 to Lerman discloses a supportive brace which includes lateral and medial circular hinges rotatably securing the lateral and medial sides of the leg-supporting shell to the foot supporting shell. The circular hinges are formed by relatively large area wall portions of the shells which overlie each other in the vicinity of the ankle bones projected from the lateral and medial sides of the ankle. 
         [0005]    U.S. Pat. No. 7,682,322 describes an articulated orthosis having at least one adjustable joint for articulating two hinged parts of the orthosis, the joint comprises a tensor for carrying the load applied between the two hinged parts. Compression surfaces coupled to the hinged parts are constructed to apply compression forces to a compression element when the angle between the two parts widens. Preferably the compression element comprises a block of resilient material. The joint allows adjustability of the unloaded angle between the hinged parts by varying the dimensions of the block, while selecting blocks having different compressional characteristics such as modulus of elasticity allows varying the degree of resistance to widening the angle between the two hinged parts. 
         [0006]    In view of the aforementioned there is a need for an AFO joint design that allows for adjustability and is biomechanically designed for shock absorption and anti-flexion to help with knee stability upon heel contact (i.e. heel strike). Further, there is a need for an AFO with structural characteristics which resist torsional rotation of an AFO when placed in a brace. Further, there is a need to provide an AFO with an improved tensioning member that includes a low profile that limits rotation of brace components and enhances tensioning at the interface of the brace components. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  shows a top perspective view of an AFO Joint. 
           [0008]      FIG. 2  is a top plan view of the AFO Joint as shown in  FIG. 1 . 
           [0009]      FIG. 3  is a side elevation view of the AFO Joint as shown in  FIG. 1 . 
           [0010]      FIG. 4  is a bottom plan view of the AFO Joint as shown in  FIG. 1 . 
           [0011]      FIG. 5  is a front elevation view of the AFO Joint in  FIG. 1 . 
           [0012]      FIG. 6  is a top perspective view of a tension member. 
           [0013]      FIG. 7  is a side elevation view of the tension member of  FIG. 6 . 
           [0014]      FIG. 8  is a top plan view of the tension member of  FIG. 6 . 
           [0015]      FIG. 9  is a bottom plan view of the tension member of  FIG. 6 . 
           [0016]      FIG. 10  is a top perspective view of a mold blank. 
           [0017]      FIG. 11  is a top plan view of the mold blank as shown in  FIG. 10 . 
           [0018]      FIG. 12  is a side elevation view of the mold blank as shown in  FIG. 10 . 
           [0019]      FIG. 13  is a bottom plan view of the mold blank as shown in  FIG. 10 . 
           [0020]      FIG. 14  is a front elevation view of the mold blank in  FIG. 10 . 
           [0021]      FIG. 15  is a perspective and partially transparent view of another embodiment of an AFO Joint. 
           [0022]      FIG. 16  is a top partially transparent view of the AFO Joint shown in  FIG. 15 . 
           [0023]      FIG. 17  is a perspective view of a resistance member used in the alternative embodiment of  FIG. 15 . 
           [0024]      FIG. 18  is a top view of the resistance member of  FIG. 17 . 
           [0025]      FIG. 19  is a side view of the resistance member of  FIG. 17 . 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views. As best illustrated in  FIGS. 1-3  the disclosed embodiment of an AFO joint  10  generally includes a body  15 , a tension aperture  13  and a tension member  50  (described below). As discussed in further detail below, AFO joint  10  is configured in a manner to provide a single body external structure used in conjunction with an orthotic, such as a brace. In an embodiment, AFO joint  10  can be used to provide support for and limit the range of motion of the respective leg and foot portions of an ankle foot orthotic. 
         [0027]    Body  15  typically comprises a beam  20 , a sidewall  25 , an angular wall  30  and a base  12 . These several portions form a single structure for supporting a tension member  50 . As shown in  FIG. 1-5 , body  15  may be made of silicon, polyurethane, polypropylene, and/or other similar materials. Other materials, such as composite plastics and injection molded plastics, may also be used to form body  15 . 
         [0028]    As best shown in  FIG. 1 , an elongate surface such as beam  20  is positioned along the medial section of body  15 . Although many configurations are within the scope of the invention, beam  20  is positioned between two opposing tension apertures  13  which will support the hub  60  of tension member  50 . Referring now to  FIGS. 1 ,  3  and  5 , beam  20  is shown with a curved outer surface. This feature will limit flexion of AFO joint  10  when in use. To further reduce movement, beam  20  is connected to angular wall  30  with an intersection plane  40  which is structured to reduce the rotational movement of AFO joint  10  when operably attached to a brace. The intersection point between angular wall  30  and beam  20  with intersection plane  40  may be a sharp corner or curved to further secure AFO joint  10  to a brace. 
         [0029]    Sidewall  25  runs along the side periphery of the AFO joint  10 . As best shown in  FIGS. 1 ,  2  and  4 , sidewall  25  comprises concave portions  27  which terminate along sidewall  25  to form an apex  45 . Concave portions  27  permit flexion of body  15  within the transverse plane shown in  FIG. 3 . This structural arrangement will further improve the stability of AFO joint  10  when in use. As best shown in  FIG. 1 , sidewall  25  is rounded at the front and back ends in a symmetrical manner. However, it should be appreciated that the shape and configuration of the sidewall  25  can modified to provide additional support and functionalities. 
         [0030]    As shown in  FIGS. 1 ,  2  and  4 , tension aperture  13  is positioned on two opposed end portions of AFO joint  10 . Tension aperture  13  provides an access point to tension member  50  when AFO joint  10  is being adjusted for a particular patient. Referring now to  FIGS. 6-9 , tension member  50  generally comprises hubs  60  and a connector, such as band  55 , positioned therebetween. Tension member  50  is positioned within the internal portion of body  15  and provides tensile strength to the AFO joint  10 . In an embodiment, the connector is a band  55  comprised of wrapped wire to allow for high strength and a low profile. Band  55  may be formed from wrapped wire that is shaped and hardened. Band  55  can be pinched in the generally medial portion to improve flexibility and elongation. As best shown in  FIGS. 6 ,  8  and  9 , band  55  is pinched to make an inflection region, but is not tied or fixed to a center area. The two vertical beams  57  are allowed to straighten before a static load maxes out the length of the wrapped wire. In another embodiment (not shown), band  55  is made from a metal that will bias the AFO joint back to a straight position every time that the AFO joint is flexed. 
         [0031]    Hub  60  generally comprises a neck  65 , a base plate  70  and a support plate  85 . Neck  65  generally has an elongated columnar shape and defines a threaded cavity adapted to receive a complementary threaded member. The elongated neck  65  provides an enhanced threading interface for adjusting the AFO joint  10 . Base plate  70  and support plate  85  retain band  55  and prevent the sliding of band  55  along neck  65 . Referring now to  FIGS. 6 and 9 , base plate  70  generally includes at least one side recess  80 . Side recess  80  is generally adapted to engage complementary structure integrated into a portion of the brace, such as a boss located on an outer surface of the brace. In an embodiment, the boss occupies recess  80 , thereby interfering with and substantially inhibits further rotation of hub  60 . Although no particular number of side recesses  50  is preferred, the embodiment shown in  FIGS. 8 and 9  depict base plate  70  with four side recesses  80 . Referring specifically to  FIG. 9 , base plate  70  may further comprise a hex insert  75  to allow tension member  50  to receive and be supported by an Allan wrench or similar tool while forming the AFO joint  10 . 
         [0032]    Referring now to  FIGS. 10-14 , which depict AFO joint mold blank  90  similar to AFO joint  10  described above. When AFO is being formed, AFO joint mold blank  90  is positioned with respect to an AFO to create a void that will ultimately be occupied by AFO joint  10 . Although several of the portions of the AFO joint mold blank  90  are similar to AFO joint  10  in structure, the AFO joint mold blank  90  provides limited functional benefit to an AFO. To state another way, AFO joint mold blank  90  does not include a tension member  50  or like structure, but only similar surface contours to help provide a relatively precise void for the AFO joint  10 . Referring now to  FIGS. 10 ,  13  and  14 , AFO joint mold blank  90  comprises foot pads  92  which will allow for a more comfortable contour along a patient&#39;s anatomy when the AFO joint  10  is positioned along the ankle joint. 
         [0033]    AFO joint mold blank  90  also includes a channel  95  which can be used to facilitate breaking and removing the AFO joint mold blank  90  once the AFO is form fitted. To further expedite the removal of the AFO joint mold blank  90 , the brace may include surface etching  100  which will help cleanly break the AFO joint mold blank  90  without interfering with the surrounding surfaces of the brace. These features which provide an easier removal of the AFO joint mold blank  90  and will also lessen the chance that the brace will become damaged. 
         [0034]    As best illustrated in  FIGS. 15-19 , an alternative resistance component  150  has been included in an alternative embodiment of an AFO joint  110 . In this alternative embodiment, resistance component  150  includes a resistance member  155 , a pair of hubs  160 , and a related holding body. As best illustrated in  FIGS. 17-19 , resistance member  155  is a singular strip of material, which has a relatively straight central portion, and two end portions which are curved and wrapped around hubs  160 . In a manner similar to the embodiment outlined above, hubs  160  include a central neck portion  165  and a base plate  170 . As seen, base plate  170  also includes a number of notches  180  which are provided to assist in the positioning and holding of AFO joint  110  when in use. 
         [0035]    In this alternative embodiment, it is anticipated that resistance member  155  will be fabricated from a substantially rigid metal material. For example, this metal material may be the well understood and well known spring steel, which is typically used in many spring type operations or components. As best illustrated in  FIG. 19 , resistance member  155  has a length which is substantially larger than its width. This creates a structure which is substantially resistant to flexing or bending along one direction while capable of flexing in a perpendicular direction. The relatively thinner width is better illustrated in  FIG. 18 . From this top view, it is clear that resistance member  155  is narrow (relatively speaking) from a top side. Based upon this configuration, the flexing and bending of resistance member  155  and AFO joint  110  is easily controlled and well understood by those skilled in the art. 
         [0036]    To provide context,  FIGS. 15-16  illustrate this alternative resistance component  150  within a joint body  115 . More specifically, joint body  115  is illustrated with dashed lines, so that alternative resistance component  150  can be better seen. It is contemplated that joint body  115  is shaped and sized in a substantially similar manner to body  15  discussed above and illustrated in  FIG. 1 . One skilled in the art will recognize that several alternatives are possible. 
         [0037]    In addition, it is contemplated that the AFO joint  110  of the alternative embodiment discussed in relation to  FIGS. 15-19  could be attached and adjusted in the same manner as the previous embodiments. To achieve this general commonality between embodiments, the hubs  160  and baseplate  170  are substantially the same as the hubs  60  and baseplate  70  discussed in relation to  FIGS. 6-9 . That said, the dimensions and proportions will be configured to closely cooperate with resistance component  150 . 
         [0038]    Various embodiments of the invention have been described above for purposes of illustrating the details thereof and to enable one of ordinary skill in the art to make and use the invention. The details and features of the disclosed embodiment[s] are not intended to be limiting, as many variations and modifications will be readily apparent to those of skill in the art. Accordingly, the scope of the present disclosure is intended to be interpreted broadly and to include all variations and modifications coming within the scope and spirit of the appended claims and their legal equivalents.