Abstract:
An outrigger suitable for use with a dynamic splint, the outrigger comprising a support, a lever pivotally connected to the support, and spring means cooperating between the support and the lever to urge the lever to pivot towards a first position, wherein the outrigger further comprises means for adjustably affixing the support to a mounting assembly. The spring means can comprise a coil spring or a cam and cam follower arrangement and the location of the pivot between the lever and support and a joint of a user is suitably configurable, via adjustment of the location of the outrigger on the mounting assembly to provide a substantially constant restoring force to an affected body part throughout a range of movement of the splint. The splint can be used to treat a range of body parts, including finger joints, knee joints, ankle joints, for example.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims foreign priority from United Kingdom Application No. GB 1220914.4, filed on Nov. 21, 2012, the disclosure of which is hereby incorporated herein by reference in its entirety. 
       FIELD OF DISCLOSURE 
       [0002]    This invention relates to splints, and in particular, but without limitation, to dynamic hand, wrist and arm splints. 
       BACKGROUND 
       [0003]    A splint is often used to support a joint following an injury, illness or surgical procedure. Static splints are used to immobilise a joint during the healing process, whereas dynamic splints provide support whilst allowing a certain amount of movement of the joint. Dynamic splints can also be used for rehabilitation purposes, that is to say, to encourage particular joint positions and/or to provide an exercise regime to aid the healing process. 
         [0004]    People who have suffered strokes, or who have undergone hand surgery, often develop a clawed hand, that is to say, where the fingers curl up to, or towards a fist position, which can render the hand useless. In such situations, clawing can be corrected using a static splint that restrains the fingers at extension, that is to say, extending straight from the palm of the hand. Immobilising the fingers thus can be painful over extended periods of time, and also prevents the patient from being able to grip objects because the fingers of the affected hand are unable to bend. 
         [0005]    To address these issues, but to nevertheless encourage the fingers towards extension, a range of known dynamic splints are available, which comprise springs and/or elasticated straps running along the tops of the patient&#39;s fingers, that pull the fingers towards extension, but which nevertheless allow the fingers to be bent by overcoming the spring force. Dynamic splints such as these suffer from the disadvantage of the resilient spring force increasing with increasing finger flexion, which can become tiring, or in the worst cases, causing potentially harmful snap-back as the fingers are relaxed. 
         [0006]    A known way of solving this problem is to provide the dynamic splint fitted with outriggers around which the springs or elasticated straps pass. The provision of outriggers essentially elongates the springs/elastic straps, such that the change in spring force for a given change in finger flexion is reduced. 
         [0007]    For the avoidance of doubt or confusion, the term “outrigger” used herein means an attachment for a hand, or any other type of, splint that permits a joint being treated to be placed in elastic traction, which definition is known, for example, from the Taber&#39;s Cyclopaedic Medical Dictionary (2009, issue 21, p. 1655). 
         [0008]    Another known type of dynamic split, such as that described in granted European Patent No. 1071385 develops the use of outriggers by providing moveable outriggers that are arranged to pivot about a point that is offset from the centre of movement of the joint in question. By such a configuration, although the actual spring force increases with joint flexion, the provision of a pivoting outrigger enables the force felt by the joint to be resolved in such a way that the force experienced by the finger during flexion either remains substantially the same, or reduces with increasing finger flexion. Such an arrangement can allow a dynamic splint to be used for extended periods of time, allows a user to have use of his or her hand without excessive fatigue, and alleviates the problem of snap back because the restoring force on the fingers does not increase towards maximum flexion. 
         [0009]    A known drawback of dynamic splints, such as that described in EP1071385 is the time and complexity of setting them up for individual patients because the biomechanics require the: spring tension; outrigger pivot point, position relative to the affected joint and length; support and other factors to be customised for each patient. For example, each patient needs a support plate to be moulded to fit their hand/wrist, and the length of the pivoting outriggers needs to be selected to correspond to a certain ratio of joint spacing, the outriggers need to be positioned so that they align correctly with the affected joint in question and the springs need to be appropriately selected and setup so that they act in an appropriate direction relative to the joint and outrigger axes. It is understood that a typical initial casting and set-up can take from one to several hours per patient. Therefore, whilst dynamic splints of this type offer considerable flexibility in terms of fitting and set-up, they can, nevertheless, be time consuming and difficult to set-up. 
       SUMMARY 
       [0010]    A need therefore arises for a solution to one or more of the above problems. 
         [0011]    According to a first aspect of the invention, there is provided an outrigger suitable for use with a dynamic splint, the outrigger comprising a support, a lever pivotally connected to the support, and spring means cooperating between the support and the lever to urge the lever to pivot towards a first position, wherein the outrigger further comprises means for adjustably affixing the support to a mounting assembly. 
         [0012]    According to a second aspect of the invention, there is provided a dynamic splint comprising a mounting assembly, and at least one outrigger adjustably affixed to the mounting assembly, wherein the outrigger comprises a support, a lever pivotally connected to the support, and spring means cooperating between the support and the lever to urge the lever to pivot towards a first position. 
         [0013]    According to a third aspect of the invention, there is provided a mounting assembly for a dynamic splint comprising means for adjustably affixing an outrigger thereto, the outrigger comprising: a support; a lever pivotally connected to the support; and a spring means cooperating between the support and the lever to urge the lever to pivot towards a first position, the outrigger further comprising means for adjustably affixing the support to said mounting assembly. 
         [0014]    By providing a means for adjustably affixing the support a mounting assembly, the position of the outrigger can suitably be adjusted in-situ, thus facilitating the initial set-up of a dynamic splint incorporating the outrigger, and additionally or alternatively, facilitating the subsequent adjustment of the outrigger or dynamic splint. Such a configuration may significantly reduce the set-up time and complexity of a dynamic splint incorporating an outrigger according to the invention. 
         [0015]    The pivoting connection between the outrigger&#39;s support and the lever may be of any suitable type, such as, for example, a pintle hinge assembly, a clip hinge, or a line of weakness formed at an intersection between an integrally formed lever and support, any in any case, a moveable connection allowing the lever to pivot relative to the support. The lever is preferably detachably affixable to the support to enable it to be replaced by other levers of differing dimensions. 
         [0016]    The lever pivots relative to the support and a spring means is provided to urge the lever to pivot towards a first position. The spring means may take any suitable form. In one possible embodiment, the spring means comprises a resiliently deformable member, such as a coil spring or an elasticated tie, connected to the lever and support at positions spaced apart from the pivot point. The spring means may comprise may be made from, or comprise, a shape-memory material, such as Nitinal®, that is to say, a material that does not obey Hooke&#39;s law throughout its entire range of movement. The spring force may be adjustable, for example, by providing alternative connection points for the spring means or by providing a slider assembly that allows the distance between the connector points for a spring means to be adjusted. 
         [0017]    In another possible embodiment of the invention, a first one of the lever and support comprises a cam surface arranged to cooperate with a resilient abutment of a second one of the lever and support, such that the abutment cooperates with the cam surface to urge the lever towards the first position. 
         [0018]    The outrigger comprises means for adjustably and/or detachably affixing the support a mounting assembly. Such means may comprise channel or groove in a first one of the support and mounting assembly that cooperates with a complementarily-shaped appendage of a second one of the support and mounting assembly that permits relative movement or sliding of the two. Locking means, for example, a grub screw, is suitably provided for releasably locking the relative positions of the support and mounting assembly, or an adhesive may be used for permanently, or semi-permanently, locking the relative positions of the support and mounting assembly. In one possible embodiment of the invention, either or both of the support and mounting assembly may be manufactured from a resiliently deformable, or elastomeric, material, to facilitate a relative tight friction or interference fit between the respective parts for semi-permanently locking their relative positions. 
         [0019]    The mounting assembly is suitably affixable, in use, to a patient&#39;s body and will suitably be ergonomically shaped to fit the appropriate body part. The mounting assembly may take the form of a strap that can be wrapped around a body part adjacent a joint to be treated, which strap, for example in the case of a finger support, may take the form of a glove or hand/wrist bandage. The mounting assembly may additionally comprise a stiffening means, for example, a relatively rigid plate. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0020]    Various embodiments of the invention shall now be described, by way of example only, with reference to the accompanying drawings in which: 
           [0021]      FIG. 1  is a perspective, partially cut-away and exploded view of a first embodiment of a dynamic splint in accordance with the invention; 
           [0022]      FIG. 2  is a perspective view of a first alternative outrigger for the dynamic splint of  FIG. 1 ; 
           [0023]      FIG. 3  is a perspective view of an alternative mounting assembly for the dynamic splint of  FIG. 1  or the outrigger of  FIG. 2 ; 
           [0024]      FIG. 4  is a perspective view of a second alternative outrigger for the dynamic splint of  FIG. 1 ,  2  or  3 ; 
           [0025]      FIGS. 5 ,  6  and  7  are a sequence showing a third alternative embodiment of an outrigger for the dynamic splint of  FIG. 1 ,  2  or  3 ; 
           [0026]      FIG. 8  is a perspective view of a dynamic splint incorporating an outrigger as shown in  FIGS. 5 ,  6  and  7 ; and 
           [0027]      FIG. 9  is a schematic cross-section through an outrigger and the channel of  FIG. 8 . 
       
    
    
     DETAILED DESCRIPTION 
       [0028]    In  FIG. 1 , a dynamic splint  10  comprises a mounting assembly  12  and an outrigger  14  that is detachably affixable to the mounting assembly  12 . In many cases, such as when used for supporting fingers, the dynamic splint will be adapted to carry a plurality of outriggers  14  corresponding to the number of joints to be treated. 
         [0029]    The mounting assembly  12  comprises a channel member  16  proving an undercut channel  18  into which a correspondingly-shaped runner formation  20  integrally formed with the base  22  of an outrigger  14  can slide. The runner formation  20  is adapted to slide into the channel  18  to a desired location, and is stabilised against rocking by a pair of abutment members  24  that protrude down from the base  22  of the outrigger  14  to contact, in use, the wearer&#39;s body (not shown) on opposite sides of the channel member  16 . The channel member  16  is manufactured from an elastomeric material, such as silicone rubber, so that it can conform to the shape of an underlying body part (not shown) for a comfortable fit. By manufacturing the channel member  16  from an elastomeric material, it will be appreciated that the dimensions of the channel  18  can be made slightly smaller than those of the runner formation  20  so that the channel member  16  has to stretch to fit the runner  20  thus providing a convenient friction fit to retain the outrigger  14  at a desired position along its length. Such a configuration ready permits adjustment of the location of the outrigger or outriggers  14 , for example, so that they can be aligned, in the case of a finger splint, with the wearer&#39;s knuckles. 
         [0030]    A supplementary locking grub screw  21  is also provided in the outrigger, which can be screwed down into the base of the channel  18  to semi-permanently lock the outrigger  14  in position. 
         [0031]    The channel member  16  is held in place by an adjustable, elasticated strap  26 , which passes through holes  28  provided at opposite ends of the channel member  16 . The strap shown in  FIG. 1  is of a very simple design, but it will be appreciated that the strap  26  could be replaced by straps of differing designs depending on the ergonomics of the body part (not shown) to which the splint  10  is affixed. 
         [0032]    The outrigger  14  comprises a support member  28  which is formed as an injection moulded plastics block. The runner formation  20  is integrally formed with the support to provide a unitary assembly. One end of the support member  20  comprises an inverted-U shaped formation  30  that provides a resilient connector that engages with a cross-bar  32  integrally formed at the base of a lever  34 . The lever  34  can thus be clipped onto the support member  28  and is free to pivot about the cross-bar  32 , which pivot axis, it will be noted, is offset relative to the pivot axis of a joint (not shown) being treated. 
         [0033]    The free end  36  of the lever  34  comprises an additional, upper cross-bar  38  to which one end of a helical coil spring  40  is connected via hook portion (not clearly visible) formed at the end of the spring  40 . The other end of the spring  40  is similarly connected to a hook  42  that is integrally formed with a slider  44  that is arranged to slide within a channel  46  formed in the upper surface of the support member  28 , and which can be locked in place by a grub screw  47 . By such an arrangement, the tension in the spring and/or the neutral position of the lever  34  can be adjusted by adjusting the position of the slider  44  relative to the support member  28 . 
         [0034]    The free end  36  of the lever  34  additionally comprises a perpendicularly-extending limb portion  48 , which carries, at its free end  50 , a pair of lugs  52  to which a support sling  54  can be affixed by passing the lugs  52  one of a selection of through holes  56  in the sling  54 . Once properly adjusted, the free ends  58  of the sling  54  can be trimmed off, if desired. 
         [0035]    The dynamic splint  10  thus addresses certain problems associated with known dynamic splints, for example: 
         [0036]    By providing an adjustable mounting assembly  12 , the need to form a mould of a wearer&#39;s body part is removed, which can considerably reduce initial fitting and set-up times. Also, by providing an adjustable connection between the outrigger(s)  14  and the mounting assembly  12 , the need to glue, reposition and re-glue the outriggers to the mounting assembly is removed, thus greatly simplifying the initial fitting of a dynamic splint. Further, by allowing the location of the outrigger(s) to be adjusted, allowing the lever(s) to be detachable, by enabling the spring tension and/or neutral point to be adjustable, initial set-up and subsequent re-adjustment of the dynamic splint is greatly facilitated. It will be appreciated that the dynamic splint of the invention still affords a great deal of flexibility and configurability in terms of set up and adjustment, without compromising on utility, ergonomics or efficacy. 
         [0037]    In many situations, the initial set-up parameters of a dynamic splint are standardised, or lie with a small range, and so the need for all of the adjustment capabilities of the device shown in  FIG. 1  may not be necessary or desirable. In such a situation, a simplified version of the outrigger, such as that shown in  FIG. 2 , may suffice. 
         [0038]    In  FIG. 2 , the outrigger  12  is substantially the same as that shown in  FIG. 1  and identical reference signs have been used to identify identical features to avoid repetition and to aid intelligibility. The main difference between the simplified version of the outrigger  14  shown in  FIG. 2  and that of  FIG. 1  is the omission of the slider  44  for adjusting the spring  40  tension and neutral position. In this embodiment of the invention, these parameters can still be adjusted, albeit by substituting the spring  40  for one of a different length or Hooke constant: the spring  40  being detachably affixable to the support member  28  and the lever  34  by a hook  42  and upper cross-bar  38 , respectively. In addition, it will be noted that the lever  34  of the simplified embodiment can still be interchanged by un-clipping it and replacing it with another lever of differing dimensions. 
         [0039]      FIG. 3  shows an alternative type of mounting assembly  12  for outriggers (not shown) of the type previously described. The mounting assembly  12  comprises a channel member  16  functionally similar to that previously described, the channel member  16  being integrally formed with a rigid or semi-rigid support plate  60  that is stitched to the exterior surface (in the illustrated embodiment) of an elasticated wrist support  62 . It will be appreciated that the wrist support  62  shown could be substituted for another type of support depending on the ergonomic requirements of the wearer, for example, the dynamic splint  10  could be fitted to a knee, ankle, elbow or other joint support. The wrist support  62  comprises a web of flexible elasticated textile that can be wrapped around a body part (in this case the hand and wrist) adjacent a joint to be treated (in this case a knuckle joint). The wrist support comprises a hook and loop type fastener that enables a wearer to adjust the tightness of the support  62  to personal requirements. 
         [0040]    The provision of an integrally-formed support plate serves to stabilise the channel member  16  on the back of the user&#39;s hand, thus allowing the tension in the spring  40  to be transmitted between the lever  34  and the wearer&#39;s body in a predictable and controlled manner. 
         [0041]    It will also be noted, in  FIG. 3 , that the simple slings  54  shown in  FIGS. 1 and 2  have been substituted for tubular finger ring portions  64  that are made of a relatively inextensible textile and which have eyelets  66  formed on their intended upper surfaces that connect to the finger ring portions  64  via small support plates  68 . The eyelets  66  can be connected to the upper cross-bars  38  of the levers  34  previously described, by relatively inextensible linkages to allow the spring force to be used to urge the fingers toward extension via the levers  34 . 
         [0042]      FIG. 4  shows a yet further alternative embodiment of the outriggers  14  in which the spring  40  previously described has been replaced by a sprung cam assembly  70 . A known problem, associated with existing dynamic splints, such as that described in EP1071385, is that there is a tendency for the outriggers and/or springs to snag on foreign objects, especially clothing, and most especially sleeves of clothing when they are being put on, or removed, by a user. In the embodiment of  FIG. 4 , the coil-sprung arrangement has been replaced by a cam-type spring arrangement, which reduces the likelihood of snagging on foreign objects. 
         [0043]    The outrigger  14  of  FIG. 4  comprises a support member  28  having an integrally formed runner  20 , and a pivotally connected lever  34 , similar to that previously described. In this example, the lever  34  is pivotally connected to the support member  28  by a pair of outwardly extending bosses  72  that engage with through holes or recesses formed in a clevis  74  formed integrally with the support element  28 . The lever  34  can be removed and replaced by prising the clevis  74  apart to free the bosses  72  from the through holes or recesses in an manner that will be readily apparent to the skilled person. 
         [0044]    The lower end  76  of the lever  34  comprises an integrally formed cam portion  78  that extends radially outwardly from the axis of the bosses  72 , which cam portion  78  is adapted to slide against and cooperate with, a resiliently deformable cam follower plate  80  formed integrally with the support member  28  of the outrigger  14 . The lever  34  is thus urged towards an upright (as shown in the drawings) neutral position by the action of the cam portion  78  on the cam follower  80 , but is free to pivot about the axis of the bosses  72  by the cam portion  78  resiliently deforming the cam follower  80 . The lever  34  is thus biased towards the neutral position, which effect can be used to provide the therapeutic force required for the effective operation of the dynamic splint. It will be appreciated that the neutral position and the spring force can be selected by the appropriate selection of the geometry of the cam member  78  and the cam follower  80 . Specifically, by purposively designing the profile of the cam and cam follower, it is possible to tailor the restorative spring force to be zero at, or through, several angles of rotation, thus enabling the spring force to be matched more precisely to biomechanical requirements. 
         [0045]    Further, the embodiment of the invention of  FIG. 4  has been depicted with a generally upright lever arrangement and with a cam and cam follower located on top of the support. This is merely an exemplary embodiment and has been depicted thus to facilitate direct comparison with the embodiments shown in  FIGS. 1 and 2 . Nevertheless, it will be appreciated that the lever and cam could be reconfigured such that the neutral position of the lever is more in-line with the user&#39;s hand, meaning that it protrudes upwardly less from the back of the user&#39;s hand, and/or the cam could be formed to face downwardly with the cam follower abutting it from below, to provide a flatter overall design that poses a yet lesser snagging hazard. 
         [0046]    In  FIGS. 5 to 7 , another embodiment of an outrigger  100  in accordance with the invention comprises a main body portion  102  moveably affixable, in use, to a support structure  60 , such as that shown in  FIGS. 3 and 8 . The main body potion  102  comprises a generally cylindrical hollow interior volume  104 , which houses a helical compression spring  106 . The spring  106  acts upon a disc  108 , which is integrally formed with a clevis  110 , which pivotally connects to one end  112  of a first linkage  114 . The opposite end  116  of the first linkage  114  connects to a first end  118  of a second linkage  120 , whose opposite end  122  connects, in turn, to a lever  124 . The lever  124  is pivotally connected to an extension  126  extending from the main body portion  102 . 
         [0047]    As can be best seen in  FIGS. 6 and 7 , the extension  126  has a part-rounded  128  and a part squared-off  130  portion which limits the movement of the lever  124  between a fully-extended, straight position (as shown in  FIG. 5 ) through an intermediate position (as shown in  FIG. 6 ) and to a fully-bent position (as shown in  FIG. 7 ). 
         [0048]    The lever  124  is biased towards the straight position (as shown in  FIG. 5 ) by the action of the spring  106  acting through the two linkages  114 ,  120  on the lever  124 . Because there are two linkages  114 ,  120 , the disc  108  is able to travel linearly along the interior of the hollow interior volume  104  of the main body portion  102  as any vertical offset is accommodated by the relative movements of the linkages  114 ,  120 . Moreover, the force-extension curve, that is to say, the biasing force applied by the spring to the lever at different points of travel, can be tailored by adjusting the length of the spring  106  and the length of the levers. In the illustrated embodiment, the forces are resolved such that the restoring force urging the lever to the extended position (as shown in  FIG. 5 ) is substantially the same at all positions. A constant force has been shown to provide positive therapeutic benefits when used in a splinting device because it alleviates fatigue and allows the wearer to use the affected body part, e.g. finger, leg, arm, throughout its entire range of movement, that is to say, without excessive resistance at the extremes of movement and without “force fade” as the affected body part is straightened. 
         [0049]    It will be noted that the construction shown in  FIGS. 5 to 7  inhibits losing the spring  106  because the squared-off end  130  of the extension  126  prevents the disc  108  form travelling beyond the opening of the hollow interior volume  104 . However, the outrigger  100  can be readily assembled by clipping the linkages together after the spring  106  and disc  108  have been located. 
         [0050]    The free end  140  of the lever  124  can be connected to a sling  54 , such as that shown in  FIGS. 1 and 2 , via a through hole  142 , as shown in  FIG. 7 . 
         [0051]    In  FIG. 7 , a dynamic splint  200  in accordance with the invention comprises a mounting assembly  12  for the outriggers of the type shown in  FIGS. 5 ,  6  and  7  of the drawings. The mounting assembly  12  comprises a channel member  16 , which is integrally formed with a rigid or semi-rigid support plate  60  that is stitched to the exterior surface (in the illustrated embodiment) of an elasticated wrist support  62 . It will be appreciated that the wrist support  62  shown could be substituted for another type of support depending on the ergonomic requirements of the wearer, for example, the dynamic splint  10  could be fitted to a knee, ankle, elbow or other joint support. The wrist support  62  comprises a web of flexible elasticated textile that can be wrapped around a body part (in this case the hand and wrist) adjacent a joint to be treated (in this case a knuckle joint). The wrist support comprises a hook and loop type fastener that enables a wearer to adjust the tightness of the support  62  to personal requirements. 
         [0052]    The provision of an integrally-formed support plate  60  serves to stabilise the channel member  16  on the back of the user&#39;s hand, thus allowing the tension in the spring  106  to be transmitted between the lever  124  and the wearer&#39;s body in a predictable and controlled manner. 
         [0053]    It will also be noted, in  FIG. 8 , that tubular finger ring portions  64  are connected to the levers  124  of the outriggers  100  via length adjustable wires  150 . 
         [0054]    In  FIG. 9  it can be seen how the outriggers  100  are connected to the channel  16  of the support plate  60 : that is to say, via a set of projections  160 . Each outrigger  100  is provided with a number of projections  160  so that the projection  162  of the outrigger beyond the channel  16  can be selected by a user. The projections  160  are also rotatably receivable in the channel  16  to permit the outriggers  100  to pivot or rotate  164  about the projection. This configuration allows a wearer of the device  200  a full range of movement and reduces transverse loading on the affected body part, as might occur if the outriggers  100  were to be rigidly affixed to the channel  16 . 
         [0055]    The invention is not restricted to the details of the foregoing embodiments, which are merely exemplary of the invention. For example, the shape and configuration of the various elements of the invention may be changed, as might their materials of manufacture. In one alternative embodiment, the finger slings shown in the drawings may be replaced by, or supplemented by, finger-tip engaging supports (similar to rigid or flexible thimbles) that fit over the tips of a wearer&#39;s fingers. The invention is not restricted to the field of dynamic finger splints, but may be applied to other joints, for example, but without limitation to, elbow, wrist, knee and ankle joints.