Patent Publication Number: US-2021186719-A1

Title: Knit Prosthetic Liner Textile With Differentiated Knit Fabric Exterior Incorporating Low Extensibility Strips

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of application Ser. No. 16/120,929 titled “Knit Prosthetic Liner Textile with Differentiated Knit Fabric Exterior,” filed Sep. 4, 2018, which claims priority to U.S. Provisional Patent Application No. 62/554,102, filed Sep. 5, 2017, the disclosure of which is hereby incorporated by reference herein. This is application is also a continuation-in-part of application Ser. No. 17/094,885 titled “Low Extensibility Strips for Prosthetic and Orthotic Application,” filed Nov. 11, 2020, which claims priority to U.S. Provisional Patent Application No. 62/938,483 filed Nov. 21, 2019 and to U.S. Provisional Patent Application No. 62/942,388 filed Dec. 2, 2019, the contents of which are incorporated by reference herein in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     This invention relates to liners for use in a prosthetic assembly. More particularly, the described invention relates to liners having a particular stitching such that the distal end of the liner has less stretch than the proximal end of the liner so as to reduce pistoning which incorporate low extensibility strips which reduce elongation in the longitudinal direction when applied to prosthetics and orthotics. 
     Description of the Background Art 
     Prosthetic liners have been in use since the 1970&#39;s, mostly custom made, and made of various materials. Silicone liners have been used since the 1980s in the prosthetic industry such as those described in U.S. Pat. No. 4,923,474 granted to Klasson and Kristinsson. Other examples of such liners include U.S. Pat. No. 5,728,168 to Laghi et al., U.S. Pat. No. 5,830,237 granted to Kania, U.S. Pat. No. 5,507,834 to Laghi et al., U.S. Pat. No. 5,443,525 to Laghi et al., and U.S. Pat. No. 5,728,168 to Laghi et al. Gel and urethane liners have also been used for prosthetic and orthotic purposes and, for the most part, have a fabric covering. The fabric covering is used to reinforce the underlying material (silicone, gel, urethane) and allows for extensibility to make it easier to don and doff the liner by rolling it on and off the residual limb 
     The liners disclosed in U.S. Pat. Nos. 5,443,525, 5,507,234, 5,728,168, 6,544,292, and 6,764,631 each represent advances in the field of fabric covered liners and the disclosures of which are hereby incorporated by reference. Additionally, U.S. Pat. No. 6,454,812, also hereby incorporated by reference, describes a liner comprising additional features attached to the liner textile to limit the vertical stretch at the distal end of a liner and is incorporated herein by reference. This method has been used successfully within the field of prosthetics to provide the liner textile with a strengthened distal end, means for attaching a threaded mechanical feature, and a boundary layer that prevents the thermoplastic elastomer from undesirably passing through the textile during high pressure processing. 
     Fabric liners having a lower longitudinal elongation at the distal end were initially popular because they prevented “pistoning.” Pistoning is the loss of suspension of a residual limb when weight is taken off of it and the resulting pushing down of the limb on the socket when weight is applied, like the piston of car. This means that every time the amputee attempted to move his/her leg, there would be a delay between when the residual limb moved and when the prosthesis moved. Pistoning is more pronounced in locking liners, i.e. liners that attach the prosthesis to the residual limb by means of a distal umbrella and distal pin with a corresponding lock. Older versions of fabric liners with lower longitudinal elongation at the distal end prevent pistoning but also constrain the knee flexion of the amputee. If a liner exhibits a high longitudinal elongation throughout its length, then the prosthesis will move up and down during ambulation. On the other hand, if there is no longitudinal elongation then the amputee will find it difficult to flex the knee. 
     In order to overcome this issue, liners with a distal matrix were developed such as the liner described in U.S. Pat. No. 6,454,812, described above. These liners include an additional fabric matrix which is knit to minimal longitudinal elongation where the matrix is bonded to the interior of the external fabric of the liner. However, this construction is expensive to construct due to the fact that the additional steps of applying adhesive to the interior of the exterior fabric, applying the reinforcing matrix to the adhesive layer, and curing of the adhesive are required. The present invention overcomes this problem by eliminating the reinforcing matrix and replaces it with a differentiated knitting of the exterior fabric. 
     There exists a need for liners with limited extensibility in localized regions of the residual limb and greater extensibility in other regions of the residual limb. Liners such as those described in U.S. Pat. No. 9,216,099 to Laghi, U.S. Pat. Nos. 9,364,347, 8,394,150, 8,852,291, 8,246,694, 8,808,294, 8,226,732, 8,357,206, 6,764,631, 6,544,292, 6,454,812, 5,728,168 and 5,507,834 each describe liners which highlight such a need. 
     U.S. Pat. No. 6,231,617 to Fay, which is incorporated herein by reference, describes the a liner which incorporates elongate arms of a strip or ribbon shape. However, a limitation of Fay is that the arms have to radiate from the distal attachment plate or mounted to a peripheral edge of the distal attachment plate. The present invention allows for the use of low extensibility strips anywhere on or in the prosthetic/orthotic without being limited to a certain location on the device. 
     Generally, the distal end of locking liners require the fabric to be less extensible in the longitudinal direction or that a polymer or other solid implement be used in order to reduce pistoning of the prosthetic implement during ambulation or movement. Other regions may benefit from reduced extensibility of the fabric cover such as in the case the above the knee amputees who may exhibits unusually fleshy residual limbs. 
     The present invention utilizes stitching with reduced stretch regions such that the distal end of the liner has less stretch than the proximal end so as to prevent pistoning. 
     Therefore, it is an object of this invention to provide an improvement which overcomes the aforementioned inadequacies of the prior art devices and provides an improvement which is a significant contribution to the advancement of the liner art. 
     Another object of the invention is to provide a liner for prosthetic assemblies that reduces pistoning of the residual limb when in use. 
     Another object of the invention is to provide a liner for prosthetic assemblies that can also be used with a locking prosthetic assembly. 
     Another object of the invention is to provide a liner that implements two or more stitching types. 
     Another object of the invention is to provide a liner with less stretch capability at the distal end than at the proximal end. 
     Another object of the invention is to provide a liner with variable stretch characteristics based on knit construction and stitching. 
     Another object of the invention is to provide strips or other shapes of low extensibility material which can be applied to the exterior of fabric liners. 
     Another object of the invention is to provide low extensibility material which, when applied to fabric liners, reduce extensibility in the longitudinal direction while maintaining extensibility in the transversal direction. 
     Another object of the invention is provide a fast and inexpensive way to reduce the extensibility of fabric liners in desired regions. 
     Another object of the invention is to provide a customizable solution for patient comfort such that a prosthetist can adhere appropriate shapes in appropriate locations in order to support or contain a region or segment of the residual limb as required by patient clinical conditions. 
     Another object of the invention is to contain the dynamic deformation of the residual limb during ambulation. 
     Another object of the invention is to provide a low extensibility material which can be cut into customer or standard shapes. 
     The foregoing has outlined some of the pertinent objects of the invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the intended invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the summary of the invention and the detailed description of the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings. 
     SUMMARY OF THE INVENTION 
     The present invention relates generally to a liner for use in a prosthetic assembly having variable stretch regions at a distal end providing different stretch regions incorporating low extensibility strips. 
     Specifically, the present invention relates to a prosthetic liner having a lower longitudinal stretch in the distal region than in either the proximal or optional intermediate region. The distal region may stretch anywhere from 0-30% vertically and 10-200% horizontally as compared to the proximal region&#39;s vertical stretch of 55-125% and 100-175% horizontally. The stretch of the liner at various pressure sensitive regions of a residual limb can also be lowered or heightened depending on the area. A variety of stitches may be used at the distal end to implement this lowered longitudinal stretch. Preferably, the liner is made of a stretchable material. The liner also has an interior layer of elastomer gel. The design of this prosthetic liner is primarily to prevent the “pistoning” of the amputee&#39;s residual limb within the liner and for comfort over pressure-sensitive areas of the residual limb. The liner also includes the use of a low extensibility material which is adhered to the fabric portion of a prosthetic liner or orthotic liner either internally or externally and limits the longitudinal movement while allowing for transversal movement. The customizable nature of the invention allows for shaping and personalization depending on the needs of the user. 
     The foregoing has outlined rather broadly the more pertinent and important features of the present invention in order that the detailed description of the invention that follows may be better understood so that the present contribution to the art can be more fully appreciated. Additional features of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and the specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present disclosure and its advantages, reference is now made to the following descriptions, taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a cross-sectional view of the present invention for use with a locking prosthetic assembly comprising two different types of stitches showing the different relevant regions; 
         FIG. 2  is a cross-sectional view of the present invention showing below-the-knee amputation pressure sensitive areas; 
         FIG. 3  is a cross-sectional view of the present invention showing below-the-knee-amputation pressure tolerant areas; 
         FIG. 4  is a cross-sectional view of the present invention showing above-the-knee amputation pressure sensitive areas; 
         FIG. 5  is a cross sectional view of the present invention showing above-the-knee amputation pressure tolerant areas; 
         FIGS. 6A-6N  are various stitching types that can be used in the distal region of the present invention to prevent pistoning; 
         FIG. 7  is a cross-sectional view of a liner incorporating the low extensibility material internally; 
         FIG. 8  is a top view of the low extensibility material in one preferred shape; 
         FIG. 9  is a top view of the low extensibility material in a second preferred shape; 
         FIG. 10  is a top view of the low extensibility material in a third preferred shape and configuration; 
         FIG. 11  is a top view of the low extensibility material in a second preferred configuration; 
         FIG. 12  is a cross-sectional view of a liner with an alternative arrangement of low extensibility material placed either internally or externally; 
         FIG. 13  is a cross-sectional view with an alternative arrangement of low extensibility material placed either internally or externally; 
         FIG. 14  is a perspective view of a wrist orthotic with the low extensibility material adhered externally; 
         FIG. 15  is a perspective view of a back orthotic with the low extensibility material adhered externally; 
         FIG. 16A  is a perspective view of an ankle orthotic with the low extensibility material adhered externally; 
         FIG. 16B  is a cross-sectional view of the ankle orthotic shown in  FIG. 16A ; 
         FIG. 17  is a perspective view of a knee orthotic with the low extensibility material adhered externally; and 
         FIG. 18  is a perspective view of an elbow orthotic with the low extensibility material adhered externally. 
     
    
    
     Similar reference numerals refer to similar parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The following description is of the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing one or more preferred embodiments of the invention. The scope of the invention should be determined with reference to the claims. 
     The present invention relates to a liner  100  for use with prosthetic devices. As shown in  FIG. 1 , the liner  100  for use with a prosthetic assembly comprises a plurality of types of stitching. The liner  100  comprises a distal region  50 , proximal region  60 , and an optional intermediate region  70 . In one embodiment, the distal region  50  that comprises the distal end  80  of the liner is constructed with a reduced vertical stretch when compared to the upper region  60  of the liner. Preferably, the distal region  80  has a vertical stretch of 0-30% and a horizontal stretch of 10-200% as compared to the proximal region  60 , which preferably has a vertical stretch of 55-125% and a horizontal stretch of 100-175%. Optionally, the intermediate region  70  may have a vertical stretch of 15-40% and a horizontal stretch of 80-120% or it may have the same stretch characteristics of the proximal region  60 . The reduced stretch of the distal region  50  is achieved on a flatbed knitting machine by use of a variety of different stitches as described below. In a preferred embodiment, the liner  100  is knit in a single piece construction with the proximal end  90  being open and the distal end  80  being closed. Alternatively, the two halves may be independently constructed and then sewn or attached together by another means to form the completed liner textile. 
     Preferably, the liner  100  is knit using computerized flatbed knitting machines that allow the use of several different yarns at the same time or sequentially in the same garment, including elastomeric fibers such as Lycra, latex, and silicone among others. These machines also allow the use of different stitch types in different areas of the same garment and controls the tension of each yarn being knitted. Further, an interior gel layer  10  resides on a limb face  22  of exterior fabric layer  30 . The gel layer  10  may be any form of stretchable elastomer as known in the industry or later developed but is preferably a styrene-based polymer. 
     In another embodiment, the liner  100  comprises regions of differing horizontal and vertical stretch stitching depending on anatomical features related to the residual limb or mechanical features related to the prosthetic socket. This means that the boundary  110  between the distal region  50  and the proximal region  60  (or intermediate region  70  if present) may shift location. The boundary  110  is preferably generally perpendicular to the central axis  120  of the liner  100 . Additionally, the distal end  70  may house a locking mechanism  130 . The use of a locking mechanism  130  requires a construction that is strong enough for the distal attachment plate  140  to be retained by the fabric or else a catastrophic failure of the prosthesis may result. Typically, such locking mechanisms  130  are secured to the fabric through the use of a grommet that bites into the fabric or other similar means of attachment. In order for the fabric to withstand the localized stress imparted by the grommet, the construction of the knit at the distal end must be heavier and stronger than the rest of the fabric cover. Such construction cannot be used in the intermediate region  70  or proximal region  60  because it would impart poor functionality to the liner and limit the user&#39;s movement. 
     More specifically, the fabric in the locking mechanism region  150  must have little to no longitudinal elongation but high circumferential elongation in order to comfortably accommodate the residual limb. The locking mechanism region  150  is limited to the area juxtaposed to the locking mechanism  130 . The thickness of the fabric in the locking mechanism region  150  should greater than the thickness of the fabric in the distal region  50 . The distal region  50 , as compared to the locking mechanism region  150 , must have a greater degree of longitudinal elongation in order to facilitate knee flexion. The intermediate region  70  may have an even greater degree of longitudinal elongation and circumferential elongation than the distal region  50  to provide greater comfort to the amputee when sitting or moving. 
     In another embodiment, the liner textile comprises regions of differing horizontal and vertical stretch depending on anatomical features related to the residual limb or mechanical features related to the prosthetic socket. There are various areas of the lower limbs that are more pressure sensitive, requiring more elongation, and various areas that are more pressure tolerant, which require less elongation. As shown in  FIG. 2 , the pressure sensitive areas for below-the-knee amputations comprise the portions of the tibia  160  such as the anterior tibia  170  and the anterior tibial crest  180  as well as parts of the fibula  190  such as the fibular head and neck  200 , and the fibular nerve  210 . These regions of the body exhibit sensitivity to pressure and therefore require a liner having greater longitudinal or circumferential elongation at those points. On the other hand, as shown in  FIG. 3 , the pressure-tolerant areas for below-the-knee amputations comprise the patellar tendon  220 , the medial tibia plateau  230 , the tibial shaft  240 , the fibular shaft  250 , and the distal end  260  of tibia  160  and fibula  190 . These regions may have more restricted longitudinal or circumferential elongation due to the tolerance these regions exhibit. 
     Similarly, as shown in  FIGS. 4 and 5 , above-the-knee amputations have similarly pressure sensitive and pressure tolerant areas. The pressure sensitive areas comprise the distolateral end  280  of the femur  270 , the pubic symphysis  300  of the pelvic bone  290 , and the perineal area  310 . The pressure tolerant areas comprise the ischial tuberosity  320  of the pelvic bone  290 , the gluteals  330 , the lateral sides  340  of the residual limb, and the distal end  350  of the femur  270 . As with below-the-knee, pressure sensitive areas of above-the-knee amputations require greater longitudinal or circumferential elongation at those points while the pressure tolerant areas may have more restricted longitudinal or circumferential elongation due to the tolerance those regions exhibit. 
     The fabric of the liner can be constructed in a number of ways so as to provide the required functionality. The functionality can be altered by using different yarns or deniers, different elastomers, different weights of elastomers, and different stitches, among other ways, to provide the right longitudinal and circumferential elongation along the length of the liner. Typical yarn types include, but are not limited to, polyester, nylon, acrylic, cellulosic, aramid, natural fibers, and metal wires. Typical elastomers include Lycra/polyurethane, natural rubber, nitrile, and silicone. Typical stitch types, as shown in  FIGS. 6A-6N , include weft ( FIG. 6A ), warp ( FIG. 6B ), stockinette ( FIGS. 6C and 6D ), garter ( FIG. 6E ), seam ( FIG. 6F ), fagoting ( FIG. 6G ), tricot ( FIGS. 6H and 6I ), elongated ( FIG. 6J ), plated ( FIG. 6K ), slip ( FIG. 6L ), dip ( FIG. 6M ), and basket ( FIG. 6N ) and are used solely in the distal region  50  of the liner  100  so as to differentiate the elongation found in the proximal region  60 . 
     The present invention relates to a low extensibility material  400  for use with prosthetic or orthotic devices using the knit design described above. As shown in  FIG. 7 , this low extensibility material  400  can be used with a prosthetic liner  100  having a distal attachment plate  140  at a distal end  80 . The low extensibility material  400  for use with a prosthetic or orthotic assembly preferably comprises a strip of material  410  preferably made of strips of silk, fiberglass cloth, and other non-elastic materials like carbon fiber and thermoplastics. The prosthetic liner  100  comprises an elastomer layer  10  having a limb face  22  and a fabric face  20  wherein the fabric face  20  of the elastomer layer  10  is adhered to the external fabric  30  of the prosthetic liner  100 . In relation to the prosthetic liner  100 , the low extensibility material  400  can be adhered to the fabric  30  either internally or externally. If internal placement is desired, the low extensibility material  400  is placed between the elastomer layer  10  and the fabric  30  in the desired region and adhered only to the fabric  30  as shown in the exploded view Part B. Preferably, the low extensibility material  400  is placed at the distal end  80  of the prosthetic liner  100  and extends towards the proximal end  90  of the prosthetic liner  100 . The low extensibility material  400  preferably extends upward towards the proximal end  90  of the prosthetic liner  100 , stopping at least an inch from the proximal end  90 , when placed at the distal end  80 . Similarly, the width of the low extensibility material  400  is between 0.5-4 inches such that it can be placed in a variety of locations and positions. 
       FIGS. 8-13  show the low extensibility material  400  is a variety of configurations.  FIG. 8  shows the low extensibility material  400  as a strip of material having a central aperture  420  with a bulged mid-region  430 . The locking mechanism  130 , as shown in  FIG. 7 , can be fed through the central aperture  420  if the low extensibility material  400  is adhered externally to the fabric  30 . As shown in  FIG. 9 , the low extensibility material  400  can also be configured to have multiple arms  440  extending radially outward from the central aperture  420 . As shown in  FIGS. 10 and 11 , the central aperture  420  is optional. The low extensibility material  400  can be shaped such that a distal strip end  450  is convex while a proximal strip end  460  is concave. This allows for the low extensibility material  400  to be placed around the distal attachment plate  140  if desired or around the user&#39;s joint without impinging on joint movement. 
     As seen in  FIGS. 12 and 13 , the low extensibility material  400  can be placed in a variety of configurations according to the needs of the user. The T-shape and single strip configuration shown are not the only configurations that would be helpful to a user and any configuration determined by a medical professional to be medically helpful can be used. 
     Use of low extensibility material  400  as described herein has been tested and conclusively shows that use of the low extensibility material  400  limits the longitudinal stretch of the liner  100  while maintaining transversal stretch. In the first table, transversal stretch was tested: 
     
       
         
           
               
               
               
               
               
            
               
                   
                   
               
               
                   
                 Reinforced 
                   
                 Not Reinforced 
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                   
                 before 
                 after 
                 change 
                 % 
                   
                 before 
                 after 
                 change 
                 % 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 1 
                 13 
                 21 
                 8 
                 61.53846 
                 1 
                 13 
                 20.375 
                 7.375 
                 56.73077 
               
               
                 2 
                 13 
                 22 
                 9 
                 69.23077 
                 2 
                 13 
                 21.5 
                 8.5 
                 65.38462 
               
               
                 3 
                 13 
                 20.125 
                 7.125 
                 54.80769 
                 3 
                 13 
                 22 
                 9 
                 69.23077 
               
            
           
           
               
               
               
               
            
               
                 Average 
                 61.85897 
                 Average 
                 63.78205 
               
               
                   
               
            
           
         
       
     
     As seen in the table above, “before” refers to the liner in a static state, meaning no weight was applied, and “after” refers to the liner at failure (i.e. until the strip tore). The number measured is circumference in inches. As can be seen from the test data, the transversal stretch was essentially the same whether the liner was reinforced with the low extensibility material  400  or not. 
     A similar test was performed testing the longitudinal stretch: 
     
       
         
           
               
               
               
               
               
            
               
                   
                   
               
               
                   
                 Reinforced 
                   
                 Not Reinforced 
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                   
                 before 
                 after 
                 change 
                 % 
                   
                 before 
                 after 
                 change 
                 % 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 1 
                 4.25 
                 4.5 
                 0.25 
                 5.882353 
                 1 
                 4 
                 4.75 
                 0.75 
                 18.75 
               
               
                 2 
                 4.25 
                 4.5 
                 0.25 
                 5.882353 
                 2 
                 4.25 
                 4.75 
                 0.5 
                 11.76471 
               
               
                 3 
                 4.5 
                 4.75 
                 0.25 
                 5.555556 
                 3 
                 4.25 
                 4.625 
                 0.375 
                 8.823529 
               
            
           
           
               
               
               
               
            
               
                 Average 
                 5.77342 
                 Average 
                 13.11275 
               
               
                   
               
            
           
         
       
     
     As can be seen from this test, the longitudinal stretch was reduced by more than half when the low extensibility material  400  was used. 
     The low extensibility material  400  can also be used with orthotics which is useful to limit joint flexion both as a therapeutic aid in the case of injuries or as a means of injury prevention. As seen in  FIG. 14 , the low extensibility material  400  works with a wrist brace  470  and can be adhered externally or internally as described above. Similarly, as shown in  FIG. 15 , the low extensibility material  400  can be integrated with a back brace orthotic  480 . Likewise, the low extensibility material  400  can be used with an ankle orthotic  490 , as shown in  FIGS. 16A and 16B , where the low extensibility material  400  preferably has a thickness to prevent ankle movement.  FIG. 17  depicts the use of the low extensibility material  400  with a knee orthotic  500  and  FIG. 18  depicts the use of the low extensibility material  400  on an elbow orthotic  510 . In all configurations when in use with an orthotic, the low extensibility material  400  can be in a strip or in a specific shape, as determined by an orthotic physician, and be adhered to the fabric  30  either internally or externally. 
     When the low extensibility material  400  is desired to be used internally, the low extensibility material  400  is first adhered to the fabric  30  on the fabric face  20  using conventional means and then the combination is placed in a mold wherein the gel, silicon, or urethane is molded over, creating a composite. Alternatively, exterior use is performed by adhering the low extensibility material  400  onto the outside of the fabric  30  in the desired location. 
     The present disclosure includes that contained in the appended claims, as well as that of the foregoing description. Although this invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention. 
     Now that the invention has been described,