Abstract:
An ankle foot orthosis that may be used for children with lower extremity spasticity or muscle weakness to prevent deformity and enhance extremity function. The orthosis includes an adjustable tension assembly connected to an upper leg portion and a lower foot portion. The tension assembly includes a tension adjuster connected with an elastomer band, with the tension adjuster being operable to selectively increase or decrease the amount of stretch applied to the elastomer band to provide a selectable upward biasing force to a patient&#39;s foot. The dynamic orthosis creates a variable load stretch below the knee preventing muscle contracture, heel cord shortening, and increases range of motion and is utilized during rest, sleep, and short distant weight bearing providing readings of the range of motion continuously. The orthosis incorporates a circumferential dynamic support system that maintains corrected alignment of the bones of the foot and ankle.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application is a continuation-in-part of U.S. nonprovisional patent application Ser. No. 12/658,427, filed Feb. 5, 2010, by Grant C. Meyer and Daniel R. Ware, which is hereby incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The present orthosis invention relates to an, ankle foot orthosis designed for increasing the range of motion and correcting the alignment of a patient&#39;s foot and ankle. 
     Children having spasticity, a condition often scene in cerebral palsy and similar types of medical disorders, are generally confronted with muscle imbalance, as their muscles do not work together in the manner of non-spastic children. The spasticity makes their muscles overpower other muscles creating unwanted pulls or forces on their joints. This imbalance of muscle pulls and involuntary forces, usually called spastic contractures, creates misalignment of involved joints. If this misalignment is not corrected and range of motion restored, it will eventually lead to permanent deformity as the child ages. 
     Plantar flexion is a normal position when the foot is flexed downward. A spastic contracture of the posterior tibial muscles (calf) can hold the foot in that position and produce a shortening of the heel cord called equinus. This type of positioning can also be seen when there is a weakening in the anterior muscles or dorsiflexors. This shortened heel cord can generate additional undesirable positions, which can lead to permanent deformity if not treated. 
     SUMMARY OF THE INVENTION 
     The present orthosis invention provides a lightweight boot for a patient to wear at night while asleep and/or at rest to increase the range of motion and correct the alignment of the foot and ankle complex. The orthosis is designed to provide adjustable dynamic stretch load to the posterior muscles and heel cord during sleep and rest to prevent contracture and shortening of the heel cord, including to lengthen and increase range of motion. The design of the orthosis provides total contact for pressure reduction, while maintaining corrected alignment. In a particular embodiment the orthosis comprises a posterior semi-rigid outer shell section joined with a foot shell section of the same material and a circumferential molded inner boot section, where the molded inner boot section retains the patient&#39;s corrected shape contours independent from the outer shell and foot shell. 
     The molded inner boot may be used in place of a pretibial shell and the tongue assembly may be reinforced with an additional layer of EVA or similar material under the dorsal strap over the foot&#39;s instep and the elastic Velcro strap attached to the tongue anterior to the tibia and fibula. The molded inner boot can be fabricated from thermal-formable foam in variable durometers, or in combination with other polymers (EVA co-polymers). The molded inner boot may be removed from the more rigid posterior outer shell if necessary for possible donning and other issues. The posterior section of the molded inner boot may be cut at the ankle axis to move in conjunction with the posterior and foot outer shells. The molded inner boot allows the natural rotation of the tibia of the ankle during dorsal and plantar flexion. The molded inner boot is fabricated from each individual patient&#39;s corrected casted mold, thereby promoting the holding and supporting of the corrected position. This corrected alignment resists the abnormal forces which are presented by the pathology that typically leads to deformity and/or progression of the anomaly. The present orthosis further comprises an adjustable tension or power pack assembly, including a power band and tension adjuster, and a variable position slotted locking plate assembly to provide stretch loads to the muscles and heel cord for achieving corrected alignment. 
     The orthosis promotes a low-load stretch during rest and sleep to improve the patient&#39;s range of motion. The orthosis foot section is pulled toward dorsiflexion by tension forces provided from the adjustable power pack assembly. The tension provided by the adjustable power pack assembly includes a tension adjuster segment, tension gauge with numerical indicia graduations, and a power band further including a slot and anchor pin located at the lower end. The tension adjuster further includes a threaded barrel insert at its upper end with a threaded bolt for insertion into the tension adjuster, and is also provided with an anchor pin at its upper end. 
     The adjustable locking assembly provides the ability to monitor and adjust the range of motion (ROM) in dorsi and plantar flexion, and also provides the patient care giver a numerical readout for indicating the patient&#39;s progress. The lightweight locking assembly can be provided with optional adjustments with a numerical monitoring (ROM) readout to a preferred dorsiflexion, plantar flexion, or other variable locked positions. 
     The orthosis has a sole and mid sole which provide a solid base of support for weight bearing and short distant ambulation. Upon weight bearing, the power pack assembly may be adjusted to relieve all tension at the ankle, allowing free motion at the ankle. The ROM can now be determined and monitored by the slotted locking plate assembly during various standing position. The forward flexion of the tibia and lower leg can be stopped at any desired position and adjusted with the locking assembly. During non-weight bearing and weight bearing, the molded inner boot is supported by the foot shell and posterior shell forces maintaining the desired corrected alignment. 
     Positioning the ankle with the adjustable locking assembly, while maintaining correct alignment throughout the foot during weight bearing use, is beneficial for optimum security and stability during walking with the present orthosis, such as for spastic patients or patients with weakened muscular ability. Locking or stopping the ankle motion at the various positions with the adjustable locking system will result in a change of ground reaction forces sent to the orthosis. These forces may be studied to provide optimum positioning for weight bearing, standing, and ambulation. A further optional design variation of the present orthosis may include an additional adjustable power pack on the opposite side. 
     The dynamic orthosis creates a variable load stretch at the ankle to prevent contracture of the heel cord and may be utilized during rest, sleep, and weight bearing use. The orthosis boot is light weight, non-cumbersome, and provides circumferential support and dynamic stabilizing forces while maintaining a corrected alignment of the bones of the foot and ankle. The orthosis boot provides range of motion improvements for dorsiflexion, thus preventing spastic contracture shortening of the heel cord, and includes monitoring and control features. The present orthosis boot is also utilized during weight bearing use and evaluation with the orthotic device providing the unique features in a simplified, lightweight, functional design. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective assembled view of an orthosis boot in accordance with the present invention illustrating a patient&#39;s foot and lower leg inserted therein and shown in a dorsiflexion position; 
         FIG. 2  is a perspective view of the orthosis of  FIG. 1  with the patient&#39;s foot and leg removed disclosing the molded inner boot assembly; 
         FIG. 3  is a perspective view of the orthosis of  FIG. 2  in the plantar flexion position; 
         FIG. 4  is a perspective view of the orthosis of  FIG. 2  in a locked position; 
         FIG. 5  is a partial perspective view of components of the orthosis in accordance with another aspect of the present invention illustrating the inter-relationship of an alternative adjustable slotted locking plate assembly with an adjustable tension assembly, and ankle joint for providing tension in the variable locking positions for ROM improvement; 
         FIG. 6  is a perspective view of the plate assembly of  FIG. 5  showing adjustable set screws for selectively setting parameters of the orthosis; 
         FIG. 7  is a partial cutaway view of the plate assembly of  FIG. 5 ; 
         FIG. 8 . is an exploded assembly view of the orthosis of  FIG. 2  disclosing the tongue removed from the molded inner boot assembly; 
         FIG. 9  is a perspective view of the molded inner boot assembly including the posterior section and the anterior section with the tongue of the inner boot and straps 
         FIG. 10  is a perspective assembled view of an alternative orthosis boot in accordance with the present invention illustrating a patient&#39;s foot and lower leg inserted therein; and 
         FIG. 11  is a rear perspective view of the orthosis boot of  FIG. 10  with the patient&#39;s foot and leg removed. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention will now be described with reference to the accompanying figures, wherein the numbered elements in the following written description correspond to like-numbered elements in the figures. In the embodiment shown in  FIGS. 1-4 , the orthosis includes a molded inner boot or inner boot assembly  1 , an upper or posterior shell  4 , and a lower or foot shell  19 , with shell  4  and shell  19  being rigidly formed of molded plastic and a sole  21  affixed to the bottom of foot shell  19 . Also included are a static strap  3   b  and a stretchable elastic strap  3   a  used to secure a patient&#39;s foot and ankle within the orthosis, such as by hook and loop fastener connections to shell  19  and shell  4 , respectively, in the illustrated embodiment. As shown in  FIGS. 1-4 and 8 , posterior shell  4  has a generally semi-cylindrical shape that conforms to the posterior lower calf and upper ankle region of a patient, with foot shell  19  including a wall portion  22  defining a heel receiving cavity and a base portion  23  that extends forward relative to wall portion  22  to provide toe support. As discussed in more detail below, the orthosis boot enables selective tensioning to be applied to a patient to stretch the patient&#39;s heel cord by applying an upward dorsiflexion force. 
     The orthosis includes an adjustable tension assembly or power pack assembly  5  connected to the posterior shell  4  and foot shell  19  forward of the joint  20 . Assembly  5  includes an upper portion with a tension adjuster  6  having numerical readout gradations, a threaded receiving bore  7  and a threaded bolt  8  that is received in bore  7 . Tension adjuster  6  includes an aperture or slotted window  6   a  through which the end of bolt  8  opposite its head  8   a  is visible to enable monitoring of the tension adjustment of assembly  5 . Assembly  5  is connected to posterior shell  4  by way of a bracket  17  mounted to posterior shell  4  by fastener  9 , where bracket  17  is generally L-shaped and includes a hole through which bolt  8  is passed with the head  8   a  of bolt  8  thereby supported on the bracket  17 . Assembly  5  also includes a lower portion with an elastomer power band segment  18 , where elastomer band  18  includes a slot  12  at one end for moveable connection to foot shell  19  at fastener or engagement pin  13 , where pin  13  is also employed to secure strap  3   b  to shell  19 . Band  18  is joined at its opposite end to tension adjuster  6  by way of another fastener  9   a.    
     Posterior shell  4  is further connected with foot shell  19  by way of connecting joint  20 , where joint  20  includes a flexible connector member  24  that is affixed within a cavity  25  of shell  4  by fastener  26   a  at one end, and is affixed within a cavity  27  of shell  19  by fastener  26   b  at its opposite end. A second joint  20   a  ( FIG. 8 ) of substantially similar construction to joint  20  is located on the opposite side of the orthosis relative to a patient&#39;s ankle, where joints  20  and  20   a  thereby enable connected pivoting motion between shell  4  and shell  19 . 
     With further reference to  FIGS. 1-4 , the orthosis boot also includes a locking plate assembly  10  that is fixedly connected to posterior shell  4  by a fastener  28  and is connected to foot shell  19  by a pin  14 , where plate  10  includes a slot  11  within which pin  14  is disposed. Plate  10  is able to move relative to pin  14  with pin  14  traveling within slot  11  as plate  10  moves relative to foot shell  19  when posterior shell  4  and foot shell  19  move or are adjusted relative to one another. Slot  11  further includes a locking slot portion  11   a  within which pin  14  may be positioned to fix the orientation of orthosis and inhibit movement of posterior shell  4  and foot shell  19  relative to one another. 
       FIGS. 1 and 2  illustrate the orthosis in a dorsiflexion position in which pin  14  is slid downward to be positioned toward at the bottom portion of an end of slot  11 . In this orientation shell  19  is unable to further pivot upwardly relative to shell  4  even under tension from assembly  5  due to the engagement of pin  14  with the bottom closed end of slot  11 .  FIG. 3  illustrates the orthosis in a plantar flexion position in which pin  14  is slid upward to be positioned toward at the top upper portion of slot  11  at the opposite end of slot  11  relative to  FIGS. 1 and 2 . As further understood from  FIG. 3 , when in the plantar flexion position the molded inner boot  1  and posterior shell  4  are tilted, as indicated by the arrow, with elastomer band  18  of assembly  5  being stretched and extended.  FIG. 4  illustrates the orthosis in the locked orientation with pin  14  positioned within locking slot portion  11   a . As understood from  FIG. 4 , the orthosis is placed in a generally 90 degree or right angle orientation when in the locked position, such as understood from the relative orientation of posterior shell  4  and foot shell  19 , with the alignment of assembly  5  correspondingly being shown when the orthosis is in the locked position. 
     As best understood from  FIGS. 5 to 7 , and as discussed in pending U.S. application Ser. No. 12/658,427, plate  10  may further include a pair of threaded holes or bores  15 , with one of bores  15  being aligned with slot  11  and the other with locking slot portion  11   a . Bores  15  receive threaded adjustment screws  16  for adjusting the amount of travel of pin  14  within slot  11  and locking slot portion  11   a . As shown in  FIG. 7 , numerical gradation or indicia  10   a ,  10   b  are provided adjacent locking slot portion  11   a  and slot  11 , respectively, that provide a visual indicator for setting and monitoring the adjustment of screws  16 . For example, by adjusting the screw  16  aligned with slot  11  to extend further into slot  11 , the amount pin  14  can travel within slot  11  is thereby decreased, which thus limits the amount of flex obtained in the dorsiflexion position—that is, the amount the foot of a patient is able to be flexed upward by the orthosis is decreased. The point at which pin  14  contacts the lower portion of slot  11  or the screw  16  associated with slot  11  may be referred to as a variable locked position as the lower shell  19  will no longer pivot upward relative to upper shell  4  even under the force of tension assembly  5 . 
     As discussed in more detail below, the tension assembly  5  and adjustable locking plate assembly  10  work in conjunction with the ankle joints  20 ,  20   a  that connect the upper posterior shell  4  to the foot shell  19  during use of the orthosis. 
     Referring now to  FIGS. 8 and 9 , the molded inner boot assembly  1  is constructed to be relatively compliant to form a padding and may be made, for example, of polyethylene or ethylene vinyl acetate (EVA), or the like. Molded inner boot assembly  1  includes a removable tongue  2  to which is affixed elastic strap  3   a  that is used to fasten tongue  2  to posterior shell  4 , where tongue  2  is formed to be positioned over the anterior foot and ankle area of a patient when the patient&#39;s foot is placed within the orthosis and strap  3   a  is secured to the rear of posterior shell  4  by a hook and loop fastener. The stretchable elastic strap  3   a  allows for tibial rotation during dorsi and planter flexion. Tongue  2  includes air holes, as well as an upper pad  29   a  and a lower pad  29   b  forming thicker portions whereat straps  3   a  and  3   b  engage with tongue  2 . 
     Molded inner boot assembly  1  further includes an upper or posterior lining section or portion  30  and a lower or anterior lining section or portion  31 , where upper lining section  30  is affixed to posterior shell  4  and lower lining section  31  is affixed to foot shell  19 . Upper lining section  30  and lower lining section  31  may be molded together as a single piece, as shown in  FIG. 9 , and subsequently separated in to two separate pieces for installation in the respective shells  4  and  19 . Posterior shell  4  includes a lower recess  32  within which upper lining section  30  is affixed to provide a smooth transition between the interior surface of posterior shell  4  and upper lining section  30  at location  33 . Lining sections  30  and  31  may be affixed to posterior shell  4  and foot shell  19 , respectively, by an adhesive. 
     As shown in  FIG. 8 , an aperture  34  is provided in the heel area of lower lining section  31  and foot shell  19  through which the orientation of a patient&#39;s heel within the orthosis may be visibly observed when fitting the orthosis to the patient to insure proper installation.  FIG. 8  further discloses that tension adjuster  6  includes a pair of legs  6   b ,  6   c , where elastomer band  18  is mounted between legs  6   b ,  6   c.    
     In operation, a patient&#39;s foot is placed within the orthosis, such as when the orthosis is in the locked position of  FIG. 4  where pin  14  is positioned within locking slot portion  11   a . Tongue  2  is then placed over the patient&#39;s foot with verification that the patient&#39;s heel is properly located by viewing through aperture  34 . Strap  3   a  is then secured over the patient&#39;s lower leg area by affixing strap  3   a  to the rear portion of posterior shell  4  and strap  3   b  is secured over the patient&#39;s upper foot portion by securing the end of strap  3   b  opposite pin  13  to the other side of shell  19 . Upon removing the orthosis from the locked position by moving lower shell  19  to remove pin  14  from locking slot portion  11   a , the adjustable tension assembly  5  may then be adjusted and used to apply an upward force to shell  19  relative to shell  4  for promoting dorsiflexion movement of the patient to prevent contracture, and to stretch and increase range of motion of the patient&#39;s heel cord. 
     Adjustable tension assembly  5  is employed to selectively adjust the amount of upward force that may be imparted to a patient. By tightening bolt  8 , tension adjuster  6  is drawn upwards along the threaded shaft of bolt  8 , where bolt  8  is held stationary via the retention of head  8   a  in bracket  17 . This in turn causes elastomer band  8  to be axially stretched, thereby increasing the upward force applied to lower shell  19  by tension assembly  5  for a given position of shell  19  relative to shell  4 . The level of tension applied may be set and monitored via the gradations provided on tension adjuster  6 , with a lower end  8   c  of bolt  8  being visible through the aperture  6   a  in tension adjuster  6  that is aligned with the gradations. Accordingly, the amount of tension applied to a patient to promote stretching of their heel cord may be progressively increased over time. 
     Still further the plate assembly  10  of  FIGS. 5 and 6  may be used in conjunction with the selective adjusting of tension assembly  5  to monitor and progressively stretch a patient&#39;s heel cord. It should be appreciated that as a patient&#39;s heel cord is stretched pin  14  will travel downward along slot  11  starting at a maximum plantar flexion position as illustrated in  FIG. 3  where pin  14  is located fully upwards within slot  11 , or in some orientation of pin  14  along slot  11  other than in the position of  FIGS. 1 and 2 . The amount of stretch may be observed and monitored by the position of pin  14  relative to the indicia provided adjacent slot  11 . To limit the amount of tension applied to a patient, or the amount of tension applied over a given range of movement of shell  19  relative to shell  4 , the screw  16  within the bore  15  associated with slot  11  may be adjusted to project further into slot  11 . When screw  16  is extended into slot  11 , pin  14  will come into contact with screw  16  and prevent further movement of shell  19  relative to shell  4 . It is desirable to obtain a normal resting position of a patient&#39;s foot in a position such that pin  14  is seated within slot  11 , such as against screw  16 , without the patient applying a downward force against shell  19 . Once obtained, screw  16  associated with slot  11  may be further retracted to allow further upward movement of shell  19  relative to shell  4 , which adjustment to screw  16  of slot  11  may be performed in combination with an adjustment of assembly  5  to increase upward tension on shell  19 . The adjustable features of the locking assembly  10 , with its variable positions, enable a care giver to adjust in predetermined positions for optimum range of motion control in dorsi and plantar flexion. 
     The orthosis may be employed to apply dorsiflexion tension to a patient until the normal resting position of a patient&#39;s foot is in a position where pin  14  is seated against the lower base end of slot  11 , such as shown in  FIGS. 1 and 2 , without the patient applying a downward force against shell  19 . With reference to the embodiments of  FIGS. 6 and 7 , this position is obtained when the screw  16  associated with slot  11  is fully retracted such that it does not impede travel of pin  14  within slot  11 . In the illustrated embodiment of  FIGS. 1 and 2 , the orthosis provides an approximate 18 to 22 degree upward orientation of shell  19  relative to shell  4  from perpendicular, such as relative to the orientation of  FIG. 4 . Monitoring of the obtained at rest orientation of a patient&#39;s foot within the orthosis may be done at night, for example, where spastic patients are in a relaxed state such that they are not applying a downward counter force to lower shell  19 . 
     The screw  16  associated with locking slot portion  11   a  may be used to provide an increased plantar flexion orientation of shell  4  relative to shell  19 , such as, for example, when fitting to patients to accommodate specific conditions of the patient. 
     Referring now to  FIGS. 10 and 11 , an alternative orthosis in accordance with the present invention is disclosed that includes a brace assembly  35  mounted to the upper shell  4  and lower shell  19 , with a tension assembly  5  mounted to the upper shell  4  and lower shell  19  at brace assembly  35  whereby brace assembly  35  functions as an anchor for tension assembly  5 . Brace assembly  35  provides support to the orthosis, and in particular with regard to higher force settings of tension assembly  5  that may be employed with larger patients, such as older or larger children, or adults. Moreover, brace assembly  35  provides additional restrictive motion to the orthosis and thereby direct the relative motion of upper shell  4  and lower shell  19  with respect to each other. Due to the similarities between the orthosis of  FIGS. 10 and 11  relative to the orthosis of  FIGS. 1-4 , not all of the like referenced parts will be discussed herein. 
     Brace assembly  35  includes an upper brace  36  and a lower brace  37 , with lower brace  37  forming a stirrup comprising a heal or base section  38  and a joint section  39 , where upper brace  36 , base section  38  and joint section  39  are constructed of a rigid material, such as aluminum in the illustrated embodiment. Upper brace  36  comprises an elongate member that is secured by fasteners to upper shell  4  to prevent relative movement thereto, including fastener  40   a  and an additional fastener that is covered by strap  3   a  in the views of  FIGS. 10 and 11 . Bracket  17  is mounted to upper brace  36  by fastener  40   a  to connect the upper end of tension assembly  5  to brace assembly  35 . 
     Base section  38  comprises a generally J-shaped member that extends from behind the heal area of shell  19  along the wall portion  22  positioned adjacent the lateral side of a patient&#39;s foot, with base section  38  being affixed to lower shell  19  by fasteners, including fasteners  40   b ,  40   c  and  40   d . As shown, fastener  40   b  is also used to retain strap  3   b  to lower shell  19  and fastener  40   c  is used to fixedly connect joint section  39  to base section  38  to prevent relative movement therebetween. Pin  13  is affixed to base section  38 , with elastomer band  18  connected to pin  13  by way of slot  12  in band  18  to connect the opposite end of tension assembly  5  to brace assembly  35 . 
     Upper brace  36  and joint section  39  are connected together for pivoting movement by a pivot pin  41  that allows upper shell  4  and lower shell  19  to move relative to each other during movement of a patient&#39;s foot. Although lower brace  37  is shown as comprising two separate components in the illustrated embodiment, that being base section  38  and joint section  39 , it should be appreciated that an alternative lower brace  37  may be constructed as a unitary member. 
     As shown in  FIG. 11 , the orthosis further includes a plate assembly  10  located on the side opposite of tension assembly  5 , where assembly  10  includes a slot  11  within which pin  14  is able to slide during relative movement of upper shell  4  and lower shell  19 . Also included on the orthosis as shown in  FIG. 11  is a flexible ankle joint  20 , with ankle joint  20  being positioned adjacent plate assembly  10 . 
     The present invention provides a lightweight orthosis to increase a patient&#39;s range of motion while providing proper foot alignment, along with comfort such as by way of the inner boot assembly, where the orthosis thus prevents muscle shortening and contracture of the heel cord and increasing the ROM. Changes and modifications in the specifically described embodiments, however, can be carried out without departing from the principles of the present invention which is intended to be limited only by the scope of the appended claims, as interpreted according to the principles of patent law including the doctrine of equivalents. For example, an additional second tension adjust assembly could be incorporated in the orthosis on the opposite side of the patient&#39;s foot to that shown in the embodiment of  FIG. 1 —that is, an additional tension adjust assembly may be provided on the medial or interior side of the orthosis in addition to tension assembly  5  shown on the lateral or exterior side. Still further, although strap  3   b  is shown as affixed to foot shell  19  on the lateral side and noted as including hook and loop connectors for fastening to the medial side of foot shell  19 , it should be appreciated that an alternative static strap for retaining the orthosis on a patient&#39;s foot may be fixedly connected to the medial side and selectively secured to the lateral side, such as by a hook and loop fastener. Moreover, an orthosis may include a strap on each side, with the straps being secured by crossing the straps over one another for additional holding force.