Abstract:
A post amputation limb protection to be applied to newly or recently amputated transtibial, transradial or transfemoral residual limbs comprises an inner soft liner for placement on and around the limb above the end of the stump, an end pad for placement over the stump, a shell for placement over the end pad and inner soft liner, medial and lateral struts for placement along the length of the limb over the inner soft liner, attachment structures on the various components and strap closures for securing the components to the limb, and a waist belt and suspensor, for attachment to the assembly to keep the assembly in place.

Description:
[0001]     This application claims benefit of U.S. Provisional Application Ser. No. 60/579,790, filed Jun. 14, 2004. 
     
    
       [0002]     This application is directed to a post amputation limb protection system and more particularly a protection system to be applied to newly or recently amputated transtibial, transradial or transfemoral residual limbs.  
       BACKGROUND  
       [0003]     The incidence of trauma to newly amputated limbs is significant and can be debilitating. This population is primarily the diabetic, dysvascular and/or patients otherwise in generally poor health. These patients are at great risk of falling and of delayed wound healing. They may never become prosthetic candidates, particularly if they fall onto their residual limb and re-open the surgical wound.  
         [0004]     Prior devices for post operative application include: 
        a) U.S. Pat. No. 5,211,667, issued to Michael Danford, shows a prosthesis for protecting a residual limb. The device comprises an upper shell lined with a soft material contoured to match the residual limb and a lower shell telescoping over the upper shell. The assembly includes slots through both shells to receive an elongated strap on the end of the sock covering the stump and fasteners on the external surface of the lower shell for attachment of the strap to the lower shell. Danforth prosthetics of Florida (now Otto Bock) offers the Danforth D-Pass stump protector, believed to be the device shown in the &#39;667 patent. This product includes a molded thermoplastic exterior shell. It is available in both left and right version, that are not interchangeable, and 7-10 sizes of each are required to meet the needs of the variety of patients. It is not provided with a waist belt suspension system nor does it include a reticulated end pad for cushioning the surgical wound.     b) Non-Weight bearing dressings—WU dressing or non-weight bearing removable rigid dressings (“removable” applies to a specific casting technique and does not refer to a device which can be reapplied after removal) is a cast application technique, not a commercially available product. These are primarily casts that are applied directly to the residual limb. Casting material, readily available in most medical facilities, provides a rigid shell. However it can be tricky to apply in a manner that will prevent pressure sores on bony prominences. They are not easily removable for wound and dressing changes. If they are removed or inadvertently slide off, re-application can cause wound trauma. Skilled operators are also required for the application of these devices so that a tourniquet effect is not created proximally. Additionally, they can not be readily post-formed to accommodate change or to make adjustments. There is also a risk of skin breakdown when a cast-like removable rigid dressing is used.     c) Flo-tech manufactures a knee extension, post amputation protective device known as APPOPS for postoperative knee immobilization. This device indicates it is covered by U.S. Pat. Nos. 5,571,209 and 5,728,165 issued to Robert Brown and assigned to Flo-Tech Orthotic &amp; Prosthetic Systems. These patents show a post operative protective socket for transtibial amputees. The device labeling includes a single piece semi-rigid plastic structure, which includes a cup-shaped base, into which the stump is placed, with the plastic structure partially surrounding the limb above the amputation site. Circumferential cuffs are attached to the rear surface of the shell for securing the hard shell to the stump. Because of its construction, multiple sizes are required for different patients and different assemblies are required for left or right application. It is also indicated that it can be used prior to progression into a weight bearing prosthetic system.        
 
       SUMMARY  
       [0008]     The limb guard assembly described herein, incorporating features of the invention, can be broadly used but is particularly applicable to high risk patients. It can also been utilized for traumatic injuries in younger and pediatric populations. Its primary intended use is in a non-weight bearing, post-operative protocol to maintain the knee in full extension, allow full hip range of motion and provide protection against trauma to the new surgical site during transfers and mobilizations of the new amputee. It provides a protective environment to the newly amputated residual limb and can be easily removed for wound inspection and dressing changes. It may be worn over surgical dressings, and is sized so that it can accommodate variations in dressing sizes and can be worn over prosthetic socks, Ace bandages or prosthetic shrinker socks. It has been found that three different sizes will generally accommodate the majority of left and right transtibial residual limbs but smaller and larger sizes can be provided. This assembly provides a low cost, easy to apply protective structure to prevent or reduce trauma following surgery. A limb guard incorporating features of the invention can be used universally for left or right sided applications. Other embodiments of similar construction are intended for transfemoral application, differing primarily in the outer appearance and size of component parts.  
         [0009]     In a preferred mode the limb guard is applied in the early post operative phase. It can be applied directly in the operating room but most frequently is applied 2-5 days post-operatively prior to first mobilization after amputation surgery. While it may be applied over surgical dressings, it is usually applied following the first postoperative dressing change, which typically reduces the bulk of the dressing. This eliminates the potential need to “refit” when the initially bulky dressing is reduced. Typically, application over a prosthetic sock, which is applied over any surgical dressings, is recommended. This allows easy subsequent removal without disruption of the surgical dressing. The limb guard is preferably worn at least at night while sleeping and during active waking hours. In particular, the device should be worn during transfers from bed to wheelchair or wheelchair to stationary chairs. This minimizes the risks of wound trauma during these transfers or the potential slip and fall during these transfers. Night time use is also important as new amputees frequently forget the amputation has occurred and attempt to get up independently in the middle of the night, fall and cause major wound traumas. Of primary concern, a fall could cause the wound to re-open, which can significantly delay healing and increase the risk of infection, which in turn might require revision of the amputation to a higher surgical level, such as above knee or knee disarticulation amputation. The same design can be used, in smaller sizes, for pediatric application or lesser extent upper limb amputees. When applied following a transtibial amputation it maintains the knee in extension reducing or preventing knee contractures. While primarily designed for short-term application of approximately 4-8 weeks to allow primary wound healing to occur, extended use is also contemplated.  
         [0010]     The limb guard incorporating features of the invention can be provided in a range of sizes and the components can be provided as permanent attachments so nursing or other allied health staff can easily disassemble them. Some of the components could be fabricated with thinner or lighter materials, reducing weight and bulk. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     The foregoing and other features and advantages of devices incorporating features of the invention will be more fully understood from the following detailed description and illustrative embodiments, taken in conjunction with the drawings in which:  
         [0012]      FIG. 1  is a front assembled view of a limb guard assembly incorporating features of the invention and showing various components of the assembly  
         [0013]      FIG. 2  shows the lateral struts used in the assembly of  FIG. 1 .  
         [0014]      FIG. 3  is a front perspective view of a distal rigid shell used in the assembly of  FIG. 1 .  
         [0015]      FIG. 4  is a front view of an inner soft liner used in the assembly of  FIG. 1 .  
         [0016]      FIG. 5   a  shows an end liner flattened prior to placement on the limb before application of the assembly of  FIG. 1 .  
         [0017]      FIG. 5   b  is a front perspective view of a second embodiment of liner of  FIG. 5   a.    
         [0018]      FIG. 6  is a front perspective view of a waist belt and “Y” suspensor used to hold up the assembly of  FIG. 1   
         [0019]      FIG. 7   a  is a front perspective view of a reticulated end pad used in the assembly of  FIG. 1 .  
         [0020]      FIG. 7   b  is a front perspective view of a second version of the reticulated end pad. 
     
    
     DETAILED DESCRIPTION  
       [0021]     Referring to  FIGS. 1-7 , a first embodiment of a limb guard assembly  10 , incorporating features of the invention, comprises an inverted “Y” suspensor  12  which is attached, at its lower end, to two conformable lateral struts  14  and, at its upper end, to a waist belt suspensor  16 . The lateral struts  14  are in turn attached, preferred using Velcro hook and loop connectors, to the outer surface of a soft inner liner  18  and to the distal rigid shell  20 . The soft inner liner  18  is wrapped circumferential around the remaining portion of the limb above the amputation site. Placed in the distal rigid shell  20  adjacent the surgical wound and immediately adjacent the lower end of the inner liner is a reticulated end pad  22 , providing an inner soft lining between the skin of the limb and the struts  14  and rigid shell  20 .  
         [0022]     As best shown in  FIG. 2 , the lateral struts  14  are formed from a flat, stiff material such as ⅛″ to 3/16″ thick thermoplastic copolymer. They are approximately from about 1″ to about 2″ wide, preferably 1½″ wide and approximately 18″ long, the width and length being chosen to best adapt to the size of the limb being fitted. A length of Velcro hook fasteners  24  are applied to both sides along a substantial length of the strut, with one side being provided for adhesion directly onto the inner liner  18  and the second side for receiving circumferential securing straps  44 . A “D” ring  28  is pivotably attached to allow for attachment of the inverted “Y” suspensor  12 . In a preferred arrangement the D ring is located above the patella once assembled.  
         [0023]     Alternatively, the struts  14  can be constructed of a malleable metal such as aluminum with Velcro fasteners attached thereto so that the struts can be contoured to the residual limb to accommodate angulations. Still further, the struts  14  may be constructed of a composite material to reduce the weight and bulk. Alternative plastic materials include, but are not limited to, ABS, Kydex or polyethylene.  
         [0024]      FIG. 3  shows an embodiment of a distal rigid shell  20 . The distal rigid shell  20  is formed in a conical shape larger than but generally matching the contour of a limb stump following amputation. The shell  20  is preferably molded from polyethylene, polypropylene or thermoplastic copolymer materials having similar physical properties. The molded shell  20  is generally between 0.125 and 0.175 inches thick, with lateral projections  30  extending upwardly approximately 5 inches. The rigid shell depth (the lower area which receives the stump) is approximately 1.5 inches along its anterior and posterior margins. Both the inner and outer surface of the lateral extensions include Velcro compatible material (not shown) so that components placed within or external to the shell  20  can be attached to the shell  20  using the Velcro hook and loop fasteners. The extensions  30  on the rigid shell  20  are flexible to allow contouring to the residual limb. As with the struts, the shell  20  can also be fabricated from a variety of materials including composites, aluminum, or other thermoplastic polymers. The inner dimensions of the lower portion of the rigid shell determines the sizing of the limb guard being required as the diameter of the residual limb or the amputated stump (with dressing or sock) is received within that lower portion. Generally, a diameter from about 3″ to about 8″ is adequate with most patients being properly fitted with a 4″ 5″ or a 6″ diameter rigid shell. Smaller sizes accommodate some upper limb amputations and juvenile or pediatric applications; sizes larger the 6″ are required for obese or very athletic patients with muscular limbs.  
         [0025]     The inner soft liner  18  shown in  FIG. 4  is a foam and/or fabric wrap system that has a Velcro compatible fabric outer surface. It is preferably formed of a reticulated foam sandwich type construction, approximately ⅜ of an inch or 1 centimeter in thickness. The wrap  18  is constructed such that it can wrap around the residual limb and be easily customized to fit if necessary. Velcro hook tabs  32  are attached to one end so that, once wrapped around the residual limb they can be adhered to the outer surface of the wrap  18 . When the limb guard assembly is removed it can be washed and reapplied to the limb. Alternative materials for the inner liner  18  include molded thermoplastic foam, such as plastizote, aliplast or EVA or other similar functioning materials. However, these alternative materials may require custom molding and forming to the patient, thus increasing the fitting time. Other similar foam or fabric materials can be used, allowing thicker or thinner inner liners to be utilized.  
         [0026]      FIG. 5   a  shows one embodiment of a soft end liner  34 . The end liner  34  consist of a flat component that has trifurcations  36  on either sides. This allows the middle tab  38  to be folded up around the residual limb. The end tabs  40  are then folded around on either side and held in place with Velcro tabs  42  onto the inner liner  18  providing a smooth inner surface. The end liner  34  can be cut and trimmed easily to accommodate the distal residual limb shape. Like the inner liner, the soft end liner  34  can alternatively be fabricated from platesoed or Plastizote or other similar materials but would require custom fabrication to do so. Alternative material for this inner liner  34  could be a molded thermoplastic foam such as Plastizote® (an inert, closed-cell, cross-linked polyethylene foam), Aliplast® (a cross-linked, polyethylene foam) or EVA. Other similar foam type materials can be used, which may allow either thicker or thinner end liners to be utilized. The limb guard assembly  10  may be applied to patients without using this end liner  34 , particularly on the larger residual limbs where its use is optional and not required. This is a clinical judgment to be determined by the professional doing the application.  
         [0027]      FIG. 5   b  is a second embodiment of the soft liner  134 . This embodiment has a middle portion  138  which is folded up around the residual limb tabs  140 , are then wrapped around either side of the limb and secured using Velcro tabs  142 .  
         [0028]     An embodiment of the waist belt  42  with the inverted wide suspensor  16  is shown in  FIG. 6 . The waist belt portion  42  is made long enough so that it can be used on a broad range of patients, typically 46-48 inches long. It is intended to be universal in size and can be used to hold the limb guard applied to either right or left side amputations. This is accomplished by providing the inverted “Y” suspensor  12  with Velcro fasteners for attachment onto the circumferential waist belt at a desired location on the left or right side. The waist belt may be attached to the waist of the user by any of the numerous buckles or attachment means used to secure belts. The inverted “Y” suspensor  12  provides direct vertical suspension of the limb guard assembly  10 . It does not create an abduction or abduction component at the hip and provides rotary stability as well. It also serves to maintain the knee in extension. The waist belt is also of sufficient length for a smaller individual to use as a shoulder suspensor over the contra-lateral shoulder. An extension (not shown) can also be added so that the belt can be used by obese individuals in an over-the-shoulder arrangement.  
         [0029]     Alternatively, various waist belts and prefabricated pelvic belt/hip attachments can be utilized. One skilled in the art will recognize that, based on the teachings herein, various different belt arrangements can be used. Alternative constructions include alteration of the width and length of the waist belt to accommodate varying sizes. The waist belt can also be tailored and contoured if desired.  
         [0030]     A preformed reticulated end pad  22  as shown in  FIG. 7   a  is placed within the distal rigid shell  20 . The cup shaped open cellular reticulated foam pad  20  is provided in various sizes and diameters to coincide with internal dimensions of the distal rigid shell  20 . The reticulated end pad  20  in combination with the soft end liner  34  provides a soft foam cushion between the stump and the shell  20 . Alternatively, rather than a preformed fixed size foam cup as shown in  FIG. 7   a,  the cup can be formed of foam sheet such as shown in  FIG. 7   b  which can abe sized to each individual patient and held in that shape by a Velcro fastener  23 . As a further alternative, a urethane foam pad can be employed. This has the advantage of being of a somewhat lower cost. However, if it is of a closed cell construction it will not allow air flow on the distal residual limb. Alternatively, a “temper” foam type pad could be used. This is slow recovery foam that allows good impact dispersion but generally is a much higher density and therefore does not provide as soft padding distally.  
         [0031]     To apply the limb guard assembly  10 , the patient is placed in a supine position with the knee maintained in full extension. The inner soft liner  18  is wrapped around the limb above the surgical site external to any surgical dressings, shrinker socks, ace bandages, or drains which may be in place. The reticulated end pad is placed within the shell  20  and the distal rigid shell  20  and end pad  22  are then applied to the stump and the lower end of the inner soft liner, and these components are held in place using the Velcro fasteners  32  on the inner liner  18  to provide a smooth interface between the limb and the limb guard assembly  10 . The lateral projections  30  on the distal rigid shell  20 , extending medially and laterally, are fastened by the Velcro fasteners  32  onto the inner soft liner  18 . The medial and lateral (left and right) struts  14  are applied over the soft liner  18  and adhere to the liner  18  as a result of the Velcro fasteners  24  on the adjacent faces of the struts  14 . Three circumferential strap closures  44  are then placed around the assembly securing it to the limb. A first strap closure  44  is placed at the point where the struts  14  overlap the lateral projections  30  on the rigid shell  20  to secure the struts  14  to the shell  20 . The second strap closure  44  is placed directly over the patella to maintain knee extension. The third strap closure  44  is placed at the uppermost proximal edge of the struts  14 , securing the struts to the liner  18 . The inverted Y suspensor  12  is then fastened to the D rings  28  on the struts  14 , preferably at a point approximately 24 inches above the superior patella. If not previously secured to the waist belt  42 , the Y suspensor  12  is attached to the waist belt and the waist belt is secured around the waist of the patient. As previously indicated, the waist belt can be inverted so it can be used for either a right or left amputation. The waist belt  42  should be fastened so as to provide unrestricted hip range of motion. The waist belt suspensor  16  holds the device in position while the patient is being mobilized or ambulating.  
         [0032]     The limb guard assembly  10  can be adjusted to easily accommodate varying thickness surgical dressing by readjusting the tension on the circumferential strap closures  44 . Removal of the limb guard assembly  10  is easily accomplished by opening the uppermost proximal and, middle circumferential strap closures  44 , opening the waist belt and opening the soft interface wrap  18 . To reapply the assembly  10  the process is reversed.  
         [0033]     While the limb guard assembly  10  is described with preferred materials of construction and Velcro fasteners, one skilled in the art will recognize that alternative materials and fastening systems can be used without departing from the teachings herein. Generally speaking, a limb guard assembly incorporating features of the invention includes at least two struts  14  and a distal rigid shell  20 , both of which are formed from a relatively stiff structural material. Other components, namely the inner liner  18 , the end liner  34  and the end pad  33  are of a soft compliant foam or fabric material, or combination. The waist belt suspensor assembly  16  and the circumferential strap closure  44  may be composed of materials typically used in strapping and retaining prosthetic devices or other devices on to the body of patients.