Abstract:
Disclosed is an implantable end pad. The end pad includes a bone attachment portion having a recess configured to receive an amputated bone of a residual limb. The end pad further includes an end portion having a contour corresponding to at least a portion of a socket of an artificial limb such that the end pad can be at least partially received in the socket of the residual limb. Further disclosed is a method wherein the end pad is implanted into a residual limb by way of a surgical procedure.

Description:
RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 61/498,670, filed 20 Jun. 2011, the entirety of which is herein incorporated by reference. 
    
    
     BACKGROUND 
     This disclosure relates to an implantable end pad that helps secure an artificial limb to a residual limb of an amputee. 
     Artificial, or prosthetic, limbs are typically used to replace parts lost by injury. Artificial limbs are known to include sockets sized to receive an amputee&#39;s residual limb. 
       FIG. 1  is representative of a typical residual limb  1 , including an amputated bone  2  and various soft tissue  4 . In the prior art, an artificial limb  6  may be custom fit for the residual limb  1 , such that the socket  8  is sized to receive the residual limb  1 . The residual limb  1  may be a leg amputated below or above the knee, or an arm amputated below or above the elbow, as examples. The artificial limb  6  is selected to correspond to the particular residual limb  1  and to provide a desired level of performance. The residual limb  1  may be fit with a liner or other interface to provide padding between the residual limb  1  and the socket  8 . The liner may be positioned within the socket  8  between the soft tissue  4  and the artificial limb  6 . 
     SUMMARY 
     Disclosed is an implantable end pad. The end pad includes a bone attachment portion having a recess configured to receive an amputated bone of a residual limb. The end pad further includes an end portion having a contour corresponding to at least a portion of a socket of an artificial limb such that the end pad can be at least partially received in the socket of the residual limb. Further disclosed is a method wherein the end pad is implanted at least partially into a residual limb by way of a surgical procedure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings that accompany the following detailed description can be briefly described as follows: 
         FIG. 1  illustrates a prior art artificial limb receiving a residual limb; 
         FIG. 2  illustrates an artificial limb receiving a residual limb having an example end pad; 
         FIG. 3A  is an anterior view of the  FIG. 2  end pad; 
         FIG. 3B  is representative of either a lateral or medial view of the  FIG. 3A  end pad; 
         FIG. 3C  is a representative cross sectional view at line C-C showing an example of how an amputated bone attaches to the disclosed end pad; 
         FIG. 4A  is an anterior view of another example end pad that may be used with transtibial amputees; 
         FIG. 4B  is a superior view of the end pad of  FIG. 4A ; 
         FIG. 4C  is a lateral view of the end pad of  FIG. 4A ; 
         FIG. 4D  is an inferior view of the end pad of  FIG. 4A ; 
         FIG. 5A  is an anterior view of yet another example end pad that may be used with transfemoral amputees; 
         FIG. 5B  is a lateral view of the end pad of  FIG. 5A ; 
         FIG. 5C  is a medial view of the end pad of  FIG. 5A ; 
         FIG. 5D  is a posterior view of the end pad of  FIG. 5A ; 
         FIG. 6A  is a superior view of yet another example end pad that may be used with transradial or transhumeral amputees; 
         FIG. 6B  is a lateral view of the end pad of  FIG. 6A ; 
         FIG. 6C  is an inferior view of the end pad of  FIG. 6A ; 
         FIG. 7  is representative of another example end pad having a spacer intermediate the end pad and an amputated bone; 
         FIG. 8  is representative of yet another example end pad having a liner intermediate the end pad and an amputated bone; 
         FIG. 9A  is a front view of another example end pad; 
         FIG. 9B  is a rear view of the  FIG. 9A  end pad; and 
         FIG. 9C  is a top view of the  FIG. 9A  end pad. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 2  is representative of a residual limb  10 , including an amputated bone  12  and various soft tissue  14 . In most examples, an artificial limb  16  is custom-fit for the particular residual limb  10 , such that the socket  18  is sized to receive the residual limb  10 . 
     In the example shown, an end pad  20  is received over an end of the amputated bone  12 . The perimeter of the end pad  20  is generally shaped to correspond to the socket  18 . As will be appreciated from the below, the term “correspond” as used herein means that at least a portion of the contour of the end pad  20  is shaped in a manner that mimics at least a portion of the curvature of an expected socket  18 , such that the end pad  20  provides a desired fit with the socket  18 . 
     In one example, the end pad  20  is implanted within the soft tissue  14  directly adjacent to the amputated bone  12 . When the artificial limb  16  is attached to the residual limb  10 , the socket  18  receives at least some of the end pad  20 . As shown, the example end pad  20  is encapsulated within the soft tissue  14 . In another example, a portion of the end pad  20  is exposed. Still, in further examples, the end pad  20  may be exposed such that the end pad  20  can directly engage the socket  18 . Attachment features could be provided between the end pad  20  and the socket  18  in this case, to provide a desired fit between the end pad  20  and the socket  18 . Such attachment features include placing padding (such as a sleeve) between the end pad  20  and the socket  18 , or placing some type of fastener between the end pad  20  and the socket  18 . 
       FIGS. 3A-3B  show the end pad  20  in further detail. For example, the end pad  20  generally includes a bone attachment portion  22  and an end portion  24  opposite the bone attachment portion  22 . The bone attachment portion  22  has a recess  26  for receiving the amputated bone  12 . The recess  26  may be defined between proximal (or inner, relative to the center C of the end pad  20 ) medial and lateral surfaces  28   p ,  30   p  as well as a base surface  32 , and the proximal anterior and posterior surfaces  34   p ,  36   p.    
     The lower end portion  24  may extend a distance D 1 , which can be as much as 25 mm (approximately 0.98 in) or 50 mm (approximately 1.97 in), below the bone attachment portion  22  (or, as shown, below the base surface  32 ), and is semi-spherical having an convex outer contour  40  generally defined by a radius R at an inferior surface  42  thereof. The radius R is selected to correspond to the concavity of the socket  18  and to encapsulate the end of the amputated bone  12 . While the lower end portion  24  is shown as being semi-spherical, the shape of the lower end portion  24  can be varied to correspond to different sockets  18 . 
     In the example shown, the distal (or outer) surface of the end pad  20  smoothly and continuously extends from its inferior surface  42  to its superior surface  44 . The exterior of the end pad  20  is further defined by distal (or outer, relative to the center C of the end pad  20 ) medial, lateral, anterior and posterior surfaces  28   d ,  30   d ,  34   d ,  36   d , respectively. 
     The end pad  20  may be implanted surgically by way of a surgeon attaching the end pad  20  to the amputated bone  12  immediately following amputation. This may be desirable, as the end pad  20  can be attached without requiring a patient to undergo multiple surgeries. However, the end pad  20  can be implanted post-amputation with a separate surgery. 
     In either case, an example surgical procedure would involve a surgeon displacing the soft tissue  14  to sufficiently expose the bone  12 . The surgeon may essentially “trim” the distal end  38  of the amputated bone  12  so that it continuously engages the base surface  32 . The recess  26  of the end pad  20  receives the end of the amputated bone  12 . A surgical adhesive A is then used to bond the amputated bone  12  to the end pad  20 , as shown in  FIG. 3C . The surgical adhesive A may be MediSil, for example, or another known surgical adhesive or gel. While the example end pad  20  is attached directly adjacent the amputated bone  12  via the surgical adhesive A, the end pad  20  could be indirectly attached to the amputated bone  12 , by way of an intermediate spacer S or liner L, as examples (represented in  FIGS. 7-8 ). In yet another example, the end pad  20  could be held exclusively with soft tissue  14  completely independent from the amputated bone  12  or any bone. 
     It is further contemplated, within the scope of this disclosure, that an implanted end pad  20  could be removed and replaced with another end pad of another size. For example, in the case where atrophy of the soft tissue  14  causes an undesirable fit between the end pad  20  and the socket  18  of the artificial limb  16 , the end pad  20  can be replaced with an end pad larger in size. The end pad  20  could also, in another example, be resizable by way of the injection or removal of medical grade fluid (such as silicone). 
       FIGS. 4A-4D ,  5 A- 5 D and  6 A- 6 C show three embodiments of the end pad  20 , as generally explained below. Numerals in these three embodiments generally relate to those from  FIGS. 3A-3B , above, however they include a preappended “1,” “2,” or “3.” 
     With reference to  FIGS. 4A-4D , the end pad  120  in this example is for use with transtibial, or below the knee, amputees. Due to the nature of a below the knee amputation, the distal and proximal medial and lateral surfaces  128   d ,  128   p ,  130   d ,  130   p  are generally mirror images of one another about the center C of the end pad  120  (e.g., the medial and lateral surfaces are substantially the same size and shape). 
       FIGS. 5A-5D  show an end pad  220  adapted for use with transfemoral, or above the knee, amputees. Notably, in this example, the distal and proximal lateral surfaces  230   d ,  230   p  are more pronounced than the distal and proximal medial surface  228   d ,  228   p . Whereas in the  FIGS. 4A-4D  example an even distribution of surgical adhesive A may be preferred, in this example, due to the inherent stresses and forces on a transfemoral amputee, the majority of the surgical adhesive A is desired between the amputated bone  212 , and the proximal lateral and proximal anterior surfaces  230   p ,  234   p.    
       FIGS. 6A-6C  are representative of an end pad  320  for transradial (below the elbow) or transhumeral (above the elbow) amputees. In this instance, it is desired to apply the majority of the surgical adhesive A between the amputated bone  312  and proximal superior surface  344   p  so that the most padding is provided at the distal superior surface  344   d . As in the example of  FIGS. 4A-4D , the medial and lateral surfaces  328 ,  330  are generally mirror images of one another. Notably, in this example, the socket  18  of an artificial limb  10  (in this case an arm), would attach to the distal posterior surface  334   d , unlike in the prior two examples where it would attach to the inferior surface  42 . 
       FIGS. 9A-C  show another example end pad  420 . The numerals in  FIGS. 9A-9C  correspond to those in  FIGS. 3A-3C , above, with a preappended “4.” While the end pads  120 ,  220 , and  320  are each shaped to correspond to a particular residual limb  112 ,  212 ,  312 , the end pad  420  may be “universal,” in that it can be used with any residual limb  412 . As shown, the end pad  420  is generally symmetrical about its center C, and thus its front and rear views are substantially the same (e.g.,  FIGS. 9A and 9B ). The distal surfaces of the end pad  420  generally provide the end pad  420  with a “teardrop” shape. Similar to the above embodiments, the residual limb  412  can be received within the recess  426  (e.g., using adhesive A, as noted above). Accordingly, the disclosed end pad  20  can have a variety of shapes, including, but not limited to, those shown in the  FIGS. 3A-9C . 
     Use of the disclosed end pad substantially absorbs shock and force on the amputee&#39;s residual limb, thereby increasing quality of life and allowing the amputee to walk and run longer with little to no pain. The end pad further reduces bone spurs in the amputated bone, and may restore bone canal pressure inside the amputated bone. 
     The disclosed end pad may be made of one or more appropriate materials including any number of medical grade silicones, polyurethanes, thermoplastic elastomers (TPEs), ultra high molecular weight polyethylenes (UHMWPEs), or polyetheretherketones (PEEKs) to name a few. The end pad could be formed of an appropriate hybrid biomaterial combination. At any rate, the selected material provides the amputee with adequate shock and force absorption, as noted above. 
     Terms such as “distal,” “proximal,” “anterior,” “posterior,” “superior,” “inferior,” “lateral,” and “medial” are to be construed as they would by one of ordinary skill in this art to the extent they are not otherwise defined herein. Often, in the medical field, these terms are used relative to the center of the human body. However, at certain points in this disclosure, these terms are used with reference to the center of the end pad itself, because the end pad can be used on various limbs on either side of the body. These terms are not limiting, however, and are merely used to aid in describing the structure of the various example end pads disclosed. For example, the terms “lateral” and “medial” are used to distinguish the different sides of the end pad, and are not meant to imply any specific orientation of the end pad relative to the human body. 
     Although the different examples have the specific components shown in the illustrations, embodiments of this invention are not limited to those particular combinations. It is possible to use some of the components or features from one of the examples in combination with features or components from another one of the examples. 
     One of ordinary skill in this art would understand that the above-described embodiments are exemplary and non-limiting. That is, modifications of this disclosure would come within the scope of the claims. Accordingly, the following claims should be studied to determine their true scope and content.