Abstract:
A prosthesis cover for protecting and cosmetically enhancing a prosthetic device. The prosthesis cover includes a flexible stocking portion overlapping with a flexible tubular portion. The flexible tubular portion is configured to be substantially permanently attached to the prosthetic device and to at least partially cover an outer surface of the prosthetic device. The flexible stocking portion is configured to be releasably attached to the flexible tubular portion, to at least partially overlap the flexible tubular portion, and to cover the remainder of the outer surface of the prosthetic device.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This invention relates to prosthesis coverings for an endoskeletal or exoskeletal prosthesis. More specifically, this invention is directed to an external, protective, and cosmetic flexible covering for a prosthesis, with a portion that is substantially permanently attached to the prosthesis and a portion that is releasably attached to the prosthesis. 
         [0003]    2. Background of the Related Art 
         [0004]    Advances in the science and art of creating prostheses—artificial replacements for missing body parts—has greatly increased the quality of life for myriad individuals, including young children with birth defects, soldiers returning from war, and those battling debilitating illnesses. For those who have lost a body part as a result of disease or injury, a prosthetic device provides a level of self-sufficiency and self-confidence that simply would not otherwise be possible. 
         [0005]    Prosthetic limbs, and artificial legs in particular, have advanced from simple wooden pegs to complex mechanisms that closely mimic the function of the human leg, with appropriate articulation at the knee, ankle, and foot joints. These advanced prosthetics allow amputees to walk with a more natural gait, thus reducing the wear on the artificial leg and its joint mechanisms as well as reducing the pressure and wear on the amputee&#39;s body. 
         [0006]    Typically, the prosthetic limb is attached to the amputee&#39;s body by a socket, which is custom-fitted to the remaining portion of the amputee&#39;s natural limb. The socket is also integrated with, or attached to, the internal structure of the prosthetic limb. The socket is usually made from a material such as polypropylene or laminated from a variety of fabrics impregnated with resins, and the internal structure of the prosthetic limb may be constructed from lightweight metal alloys or carbon fiber. The prosthetic limb may also include a covering. 
         [0007]    Prosthesis coverings serve two purposes: they provide a natural look to the prosthesis by incorporating skin color and texture that match those of the amputee; and they protect the prosthesis and its mechanisms from the environment, thus increasing the useful life of the prosthesis. Coverings may either be formed as part of the prosthesis or as a removable element. 
         [0008]    Soft covers made from materials such as polyurethane foam are commonly used as removable prosthesis coverings. However, use of these foam covers also requires use of a prosthetic stocking that goes over the foam cover to protect it. These stockings are prone to snags, they get dirty quickly, and they must be replaced frequently. 
         [0009]    Alternatively, a permanent, non-removable finish may be applied to the prosthetic limb. Although this option provides for greater durability when compared to stockings, when the prosthesis—inevitably—needs to be adjusted or repaired, it must be refinished, which is an expensive and time-consuming process. 
         [0010]    Another option is to use a skin-like prosthesis coverings having a straight cylindrical top and beads of silicone on the inside surface near the top. The silicone beads hold up the covering by friction alone, similar to the way that well-known thigh-high stockings are held up. These coverings are typically not trimmed to fit the curved upper edge of the prosthesis socket; doing so would cut away the resilient band and thus eliminate or reduce the frictional force required to keep the covering on the prosthesis. As a result, these coverings do not provide a uniform look along the entire length of the prosthesis. 
         [0011]    Other prosthesis covers may include a flexible skin attached to the prosthesis in a semi-permanent manner using an adhesive and cut to fit the shape of the individual prosthesis. The flexible skin is typically in a sock-like shape with a length that is greater than the length of the prosthesis. The flexible skin is applied by stretching it over the prosthesis, and attaching it to the prosthesis with an adhesive. Any excess portion of the flexible skin can then be removed by cutting or grinding. This approach provides a uniform and cosmetically appealing look and has generally worked very well. But removing the flexible skin to repair or adjust the prosthesis or simply to replace the flexible skin due to normal wear or accidental damage has proven to be problematic; the adhesive is not easily removed, thus marring the outer surface of the prosthesis. 
         [0012]    Accordingly, there is a need for methods and systems for easily applying, removing, and re-applying a new flexible skin to a prosthetic device. The skin-like prosthesis cover described in this disclosure, having a substantially permanently attached portion and a releasably attached portion, meets this need. 
       SUMMARY OF THE INVENTION 
       [0013]    To achieve these and other advantages and in accordance with the purpose of the invention, as embodied herein, the invention includes a prosthesis cover having a flexible tubular portion configured to be substantially permanently attached to a prosthetic device and to at least partially cover an outer surface of the prosthetic device. The prosthesis cover also includes a flexible stocking portion configured to be releasably attached to the flexible tubular portion, to at least partially overlap the flexible tubular portion, and to cover the remainder of the outer surface of the prosthetic device. 
         [0014]    A method of covering a prosthetic device is also disclosed. The method includes the steps of stretching a flexible sleeve around a prosthetic device such that a portion of the flexible sleeve surrounds the prosthetic device for at least a portion of the length of the prosthetic device and such that the flexible sleeve extends above a socket of the prosthetic device; substantially permanently attaching the flexible sleeve to an outer surface of the prosthetic device; trimming the portion of the flexible sleeve that extends above the socket to match a contour of the socket; stretching a flexible stocking of the prosthesis cover to surround the remainder of the outer surface of the prosthetic device; and releasably attaching the flexible stocking of the prosthesis cover to the flexible sleeve of the prosthesis cover in an overlapping manner. 
         [0015]    A prosthetic device is also disclosed. The prosthetic device includes an a outer surface, a flexible tubular portion substantially permanently attached to the outer surface, and a flexible stocking portion releasably attached to the flexible tubular portion. The flexible tubular portion at least partially covers the outer surface of the prosthetic device, and the flexible stocking portion overlaps with at least a portion of the flexible tubular portion to cover the remainder of the outer surface of the prosthetic device. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    So that those skilled in the art will readily understand how the skin-like prosthesis cover having a substantially permanently attached portion and a releasably attached portion functions, preferred embodiments of the prosthesis cover and methods of applying the cover are described in detail below with reference to the following figures: 
           [0017]      FIG. 1  is a perspective view of a below-knee prosthetic leg without a protective covering; 
           [0018]      FIG. 2  is a perspective view of the prosthetic leg of  FIG. 1  with a two-part prosthesis cover including a flexible tubular portion substantially permanently attached to an upper portion of the prosthetic leg and a flexible stocking portion releasably attached to a lower portion of the leg; 
           [0019]      FIG. 3  is perspective view of the prosthetic leg shown in  FIG. 1  with a flexible tubular portion of a prosthesis cover substantially permanently attached to an upper portion of the leg and surrounding a socket of the leg, with excess material from the flexible tubular portion extending upward above the socket; 
           [0020]      FIG. 4  is a perspective view of the prosthetic leg shown in  FIG. 3 , with the flexible tubular portion of the prosthesis cover trimmed to fit the contour of the socket of the leg; 
           [0021]      FIG. 5  is a perspective view of the prosthetic leg of  FIG. 4 , illustrating the application of a flexible stocking portion of the prosthesis cover to the leg in an overlapping manner with respect to the flexible tubular portion; 
           [0022]      FIG. 6  is a cross-sectional view taken along the line  6 - 6  shown in  FIG. 2 , illustrating a first adhesive layer between the flexible stocking portion of the prosthesis cover and the flexible tubular portion of the prosthesis cover, and a second adhesive layer between the flexible tubular portion and the leg; 
           [0023]      FIG. 7  is an alternative embodiment of the flexible stocking portion of the prosthesis cover having an elastic band near the top of the stocking portion to grip and hold the stocking onto the leg; and 
           [0024]      FIG. 8  is a perspective view of an above-knee prosthetic leg with a prosthesis cover having a flexible stocking portion applied to the leg and releasably adhered in an overlapping fashion to a flexible tubular portion of the prosthesis cover that is substantially permanently adhered to a top portion of the leg. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0025]    Both the functionality and physical appearance of a prosthetic limb are important to an amputee. The skin-like prosthesis cover described in this disclosure enhances the durability as well as the appearance of prosthetic limbs. The cover protects the prosthetic limb from wear and tear while at the same time creating a natural, smooth skin look. Advantageously, the prosthesis cover has both a substantially permanently attached portion near the socket of the prosthetic limb, providing a good fit between the amputee&#39;s residual limb and the prosthesis; and a releasably attached portion, which allows the skin-like cover to easily be removed without marring the surface of the prosthetic limb. When the releasably attached portion needs to be replaced due to normal wear and tear or accidental damage, or when the prosthetic limb needs to be repaired or adjusted, the releasably attached portion can easily be replaced without the need to replace the substantially permanently attached portion, thus avoiding the time-consuming gluing and trimming operations needed to fit the skin-like cover to the curved edge of the socket of the prosthetic limb. 
         [0026]      FIG. 1  illustrates a perspective view of a prosthetic device  10 . Although the prosthetic device shown in  FIGS. 1-7  of the drawings is a below-knee artificial leg, the prosthesis cover described in this disclosure may be used with any suitable prosthetic device, including without limitation a prosthetic leg, arm, hand, foot, finger, and toe; and with prosthetic devices of any shape, size, and construction. For example, the prosthesis cover may be configured for use with an above-knee prosthetic leg as shown in  FIG. 8 . 
         [0027]    Prosthetic device  10  is typically molded from a light-weight, plastic material such as polypropylene or laminated from a variety of fabrics and resins. Device  10  includes a socket  12 , which is custom-molded to fit the residual limb of an amputee. Socket  12  is contoured to provide a secure fit with the residual limb of the amputee, thus allowing the amputee to comfortably use prosthetic device  10  for extended periods. 
         [0028]      FIG. 2  shows a prosthesis cover  14  of the present invention in place over prosthetic device  10 . The cover not only protects prosthetic device  10  from the impacts, humidity, dust, dirt, and moisture it will encounter in everyday use, but also provides a realistic-looking approximation of human skin. In one exemplary embodiment, shown in  FIG. 2 , prosthesis cover  14  comprises two discrete parts: a flexible tubular portion  16  and a flexible stocking portion  18 . Both portions of prosthesis cover  14  may be made of a flexible polyvinyl resin material marketed as DAWSKIN and available from Daw Industries of San Diego, Calif., USA. However, other suitable materials may also be used. 
         [0029]    Prosthesis cover  14  may be manufactured by dipping, spraying, atomizing, cascading, or rolling a mold of a limb or other body part to be covered into suitable material, such as polyvinyl resin. The material is then cured on the mold to form the individual portions of prosthesis cover  14 , which can then be removed from the mold and applied to prosthetic device  10 . 
         [0030]    Flexible tubular portion  16  of prosthesis cover  14  may be in the form of a sleeve that can be stretched and fitted over an upper portion  20  of prosthetic device  10 . The material of tubular portion  16  may be substantially permanently attached to upper portion  20  with an adhesive. As used in this disclosure, the term “substantially permanently attached” or “substantially permanently adhered” means “not intended to be removed by the user in the normal course of use, but still professionally removable if needed to perform more involved repairs or other procedures to the prosthetic device.” 
         [0031]    Flexible stocking portion  18  of prosthesis cover  14  may be in the form of a stocking or sock, that is, a tubular structure with one closed end. When used with a below-knee prosthetic device, as shown in  FIG. 2 , flexible stocking portion  18  may include both a foot portion  22  for accommodating the foot area of prosthetic device  10 , and a leg portion  24  for accommodating a lower portion  26  of prosthetic device  10 . Flexible stocking portion  18  may be stretched over prosthetic device  10  until it overlaps with flexible tubular portion  16 ; flexible stocking portion is then secured to flexible tubular portion  16  rather than being secured directly to prosthetic device  10 . 
         [0032]    In one exemplary embodiment, flexible stocking portion  18  is releasably secured to a lower part of flexible tubular portion  16  using a non-permanent adhesive or using one or more bands made of silicone or other elastic material, formed on or in flexible stocking portion  18 , that will grip the lower part of tubular portion  16 . The silicone bands may be formed on flexible stocking portion  18 , similar to prior-art stocking-retention means. 
         [0033]      FIGS. 3 through 5  illustrate the application of the two-part prosthesis cover  14  to prosthetic device  10 . First, as shown in  FIG. 3 , flexible tubular portion  16  is stretched to fit around upper portion  20  of prosthetic device  10 . An adhesive may be applied to upper portion  20  prior to the application of flexible tubular portion  16  to substantially permanently secure flexible tubular portion  16  to the prosthetic device. As shown in  FIG. 3 , flexible tubular portion  16  is stretched around prosthetic device  10  such that the flexible tubular portion extends above the brim of socket  12 , which is indicated by a dotted line in the figure. 
         [0034]      FIG. 4  shows a perspective view of prosthetic device  10  after flexible tubular portion  16  of prosthesis cover  14  has been trimmed to fit the contour of socket  12  of the prosthetic device. Tubular portion  16  may be cut to size by any suitable method. In one exemplary embodiment, an adhesive is applied directly to the outer surface of upper portion  20  of prosthetic device  10 , and tubular portion  16  of the prosthesis cover is stretched over upper portion  20  of prosthetic device  10 . Once the adhesive has set, tubular portion  16  can then be cut to fit. For example, the tubular portion  16  may be cut to fit around the contours of socket  12  of prosthetic device  10 . The adhesive used may be any suitable adhesive. In one exemplary embodiment, the adhesive includes a cyanoacrylate composition that substantially permanently adheres the tubular portion  16  to upper portion  20  of prosthetic device  10 . 
         [0035]      FIG. 5  illustrates the application of flexible stocking portion  18  to prosthesis device  10  after flexible tubular portion  16  has been substantially permanently attached to upper portion  20  of the device. As shown, stocking portion  18  is stretched over lower portion  26  of the prosthetic device until it meets tubular portion  16  of prosthetic device  10 . Stocking portion  18  is then secured to prosthetic device  10  by releasably attaching an inner surface of stocking portion  18  to an outer surface of tubular portion  16  such that there is some overlap between the two portions, as indicated by the dotted line shown in  FIG. 2 . 
         [0036]    A releasable adhesive may be used to attach stocking portion  18  to tubular portion  16 . For example, the adhesive may be a cyanoacrylate composition that is diluted to enhance the releasability of the adhesive. In one exemplary embodiment, the adhesive comprises a cyanoacrylate glue diluted with acetone to form a solution that is 70% acetone and 30% cyanoacrylate glue. The same cyanoacrylate glue, without dilution, may be used to substantially permanently attach tubular portion  16  directly to prosthetic device  10 . 
         [0037]      FIG. 6  is a cross-sectional view taken along the line  6 - 6  shown in  FIG. 2 , illustrating a first adhesive layer  28  between an inner surface of flexible tubular portion  16  and an outer surface of prosthetic device  10 , and a second adhesive layer  30  between an inner surface of flexible stocking portion  18  and an outer surface of flexible tubular portion  16 . In one exemplary embodiment, first adhesive layer  28  comprises a substantially permanent adhesive, and second adhesive layer  30  comprises a releasable adhesive, that is, an adhesive that allows flexible stocking portion  18  to be easily removed from flexible tubular portion  16 . 
         [0038]      FIG. 7  illustrates an additional embodiment of a two-part, below-knee prosthesis cover. In this embodiment, flexible stocking portion  18  of the prosthesis cover has a bead or band  32 , made of silicone or another elastic material formed on the inner surface or within flexible stocking portion  18  to grip and releasably hold stocking portion  18  onto flexible tubular portion  16 , thus securing the prosthesis cover on prosthetic device  10 . 
         [0039]      FIG. 8  is a perspective view of an above-knee prosthetic leg  34  covered with a two-part prosthesis cover  36  that includes a flexible tubular portion  38  substantially permanently adhered to an upper portion of the leg  34  and a flexible stocking portion  40  releasably adhered to the flexible tubular portion  38 . The two-part prosthesis cover  36  for the above-knee prosthetic leg functions in the same way as the prosthesis cover  14  described above with respect to the below-knee prosthetic device; prosthesis cover  36  is simply sized to correctly fit the above-knee prosthetic device. In a similar manner, the prosthesis cover described in this disclosure can be a sized to fit any number of prosthetic devices. The two-part prosthesis cover described in this application allows an amputee to more quickly and easily change the prosthesis cover when desired. Removal of the cover may be necessary when the prosthetic limb needs to be repaired or altered, when the prosthesis cover needs replacement due to normal wear or accidental damage, or when the amputee simply wishes to change the color or appearance of the cover. Because the prosthesis cover is divided into two portions, there is no need for time-consuming and labor-intensive sizing and cutting when the cover is removed; the tubular portion remains in place, and the stocking portion is replaced. 
         [0040]    It will be apparent to those skilled in the art that various modifications and variations can be made to the described prosthesis cover without departing from the scope of the invention as outlined in the appended claims and their equivalents.