Polymeric prosthetic liner with controlled stretch characteristics

Abstract

A controlled-stretch prosthetic liner comprising a polymeric material covered with at least a stretch-controlling fabric. Certain liner types, such as below knee (BK) liners, may also include a panel of more stretchable fabric so as to prevent any interference with knee flexion. The polymeric material of the liner may also be used to control liner stretch, such as by adding Kevlar pulp or other materials that increase the strength and reduce the elasticity of the polymeric material and/or by reducing the amount of plasticizer(s) present therein. The stretch-controlling fabric, possibly in conjunction with the polymeric material, acts to limit the longitudinal stretch of the liner while not adversely affecting the radial stretch thereof.

What is claimed is: 
     
         1 . A controlled-stretch prosthetic liner, comprising:
 a fabric covering having an open end for introduction of a residual limb and a closed end opposite said open end;   a stretch-controlling fabric portion forming a part of said fabric covering, said stretch-controlling fabric extending from said closed end and having a limited stretch direction and a non-limited stretch direction, said stretch-controlling fabric oriented such that said limited stretch direction is directed along the length of said liner;   a two-way stretch fabric portion forming a part of said fabric covering and joined to said stretch-controlling fabric portion, said two-way stretch fabric portion located to overlie a joint of a residual limb when said liner is worn, said two-way stretch fabric portion comprised of a fabric having a range of elasticity in both directions; and   a layer of a polymeric material residing along only an interior of said fabric covering, said polymeric material extending from said closed end of said fabric covering some distance toward said open end of said fabric covering.   
     
     
         2 . The liner of  claim 1 , further comprising a docking element located at the closed end of said fabric covering for attaching the liner to a socket portion of a prosthetic limb. 
     
     
         3 . The liner of  claim 2 , wherein the closed end of said fabric covering is closed by said docking element. 
     
     
         4 . The liner of  claim 2 , wherein said docking element includes a metallic base with an internally threaded boss extending therefrom. 
     
     
         5 . The liner of  claim 2 , wherein said docking element is at least partially bonded to said fabric covering by an overlying umbrella of polyurethane. 
     
     
         6 . The liner of  claim 1 , wherein said stretch-controlling fabric has a range of elasticity in the limited stretch direction of between about 10-40%, a range of elasticity in the non-limited stretch direction of between about 70-250%, and a modulus in the non-limited stretch direction of between about 0.5-12.0 lbf. 
     
     
         7 . The liner of  claim 6 , wherein the range of elasticity of said stretch-controlling fabric in the limited stretch direction is less than 30%. 
     
     
         8 . The liner of  claim 6 , wherein the range of elasticity of said stretch-controlling fabric in the non-limited stretch direction is between about 140-190%. 
     
     
         9 . The liner of  claim 6 , wherein the modulus of said stretch-controlling fabric is between about 0.5-2.0 lbf. 
     
     
         10 . The liner of  claim 1 , wherein said stretch-controlling fabric has a weight of between about 12-22 oz./sq. yd. 
     
     
         11 . The liner of  claim 1 , wherein said stretch-controlling fabric is of rib knit construction and includes nylon 6,6. 
     
     
         12 . The liner of  claim 11 , further comprising elastic cord inserted into at least some of the courses of said rib knit fabric. 
     
     
         13 . The liner of  claim 1 , wherein said two-way stretch fabric has a range of elasticity of between about 100-130% in both directions. 
     
     
         14 . The liner of  claim 1 , wherein said two-way stretch fabric has a 50% modulus of at least about 3.25 lbf. 
     
     
         15 . The liner of  claim 1 , wherein said two-way stretch fabric forms a panel of between about 1.8-3.8 inches in width as measured radially between linear tangent points of said panel and said stretch-controlling fabric 
     
     
         16 . The liner of  claim 1 , wherein said two-way stretch fabric forms a panel having a width of between about 40-100% of the full lay-flat width of the associated liner as measured between linear tangent points of said panel and said stretch-controlling fabric. 
     
     
         17 . The liner of  claim 1 , wherein said polymeric material is a block copolymer and mineral oil gel composition. 
     
     
         18 . The liner of  claim 17 , wherein said block copolymer and mineral oil gel composition is reinforced with KEVLAR. 
     
     
         19 . The liner of  claim 1 , wherein said polymeric material tapers substantially symmetrically from a greater thickness at said closed end of said fabric covering to a lesser thickness at said open end of said fabric covering. 
     
     
         20 . The liner of  claim 1 , wherein said polymeric material is of a greater thickness at said closed end of said fabric covering than at said open end of said fabric covering and tapers substantially asymmetrically along anterior and posterior sections of said fabric covering, with said polymeric material located along said anterior portion being thicker than said polymeric material located along said posterior portion at any given distance from said closed end. 
     
     
         21 . The liner of  claim 1 , wherein a controlled-stretch portion of said liner exhibits an elasticity in a longitudinal direction of between about 15-25%, an elasticity in a circumferential direction of between about 90-130%, and has a 50% modulus in the circumferential direction of between about 1.0-2.0 lbf. 
     
     
         22 . The liner of  claim 1 , wherein said polymeric material extends along said fabric covering at least a distance that is substantially equivalent to the depth of a prosthetic socket with which said covering will be used. 
     
     
         23 . A controlled-stretch prosthetic liner, comprising:
 a fabric covering having an open end for introduction of a residual limb and a closed end opposite said open end, said fabric covering designed to control the elasticity of said liner in a longitudinal and circumferential direction;   a stretch-controlling fabric portion forming a part of said fabric covering and extending from said closed end thereof, said stretch-controlling fabric having a limited stretch direction with a range of elasticity of less than about 30%, a non-limited stretch direction with a range of elasticity of between about 140-190%, a modulus in the non-limited stretch direction of between about 0.5-2.0 lbf., and a weight of between about 12-22 oz./sq. yd, said stretch-controlling fabric oriented such that said limited stretch direction extends in the longitudinal direction of said liner, and   a two-way stretch fabric portion forming a part of said fabric covering and located within an opening in said stretch-controlling fabric portion, said two-way stretch fabric portion forming a panel of between about 1.8-3.8 inches in width as measured radially between linear tangent points of said panel and said stretch-controlling fabric, said panel joined to said stretch-controlling fabric portion and located to overlie a joint of a residual limb when said liner is worn, said two-way stretch fabric portion comprised of a fabric having a range of elasticity of between about 100-130% in both directions and a 50% modulus of at least about 3.25 lbf.; and   a layer of a cushioning block copolymer and mineral oil gel composition residing along only an interior of said fabric covering, said block copolymer and mineral oil gel composition extending from said closed end of said fabric covering some distance toward said open end of said fabric covering;   wherein said stretch-controlling fabric portion of said fabric covering is provided to limit longitudinal stretching of said liner while said two-way stretch fabric portion of said fabric covering is provided to concurrently permit adequate flexion of a joint of the amputee's residual limb.   
     
     
         24 . The liner of  claim 23 , further comprising a docking element located at the closed end of said fabric covering for attaching the liner to a socket portion of a prosthetic limb. 
     
     
         25 . The liner of  claim 24 , wherein the closed end of said fabric covering is closed by said docking element. 
     
     
         26 . The liner of  claim 24 , wherein said docking element is at least partially bonded to said fabric covering by an overlying umbrella of polyurethane. 
     
     
         27 . The liner of  claim 23 , wherein said block copolymer and mineral oil gel composition includes KEVLAR that reinforces said gel composition and assists with liner stretch control. 
     
     
         28 . The liner of  claim 23 , wherein a controlled-stretch portion thereof exhibits an elasticity in a longitudinal direction of between about 15-25%, an elasticity in a circumferential direction of between about 90-130%, and has a 50% modulus in the circumferential direction of between about 1.0-2.0 lbf., and wherein said liner in the area of said panel of two-way stretch fabric exhibits an elasticity of 60% or greater in both the longitudinal and circumferential directions, and has a 50% modulus of between about 1.0-3.0 lbf. 
     
     
         29 . A controlled-stretch below-knee prosthetic locking liner, comprising:
 a fabric covering having an open end for introduction of a residual leg and a closed end opposite said open end, said fabric covering designed to control the elasticity of said liner in a longitudinal and circumferential direction;   a stretch-controlling fabric portion forming a part of said fabric covering and extending from said closed end, said stretch-controlling fabric having a limited stretch direction with a range of elasticity of less than about 30%, a non-limited stretch direction with a range of elasticity of between about 140-190%, a modulus in the non-limited stretch direction of between about 0.5-2.0 lbf., and a weight of between about 12-22 oz./sq. yd, said stretch-controlling fabric oriented such that said limited stretch direction extends in the longitudinal direction of said liner,   a two-way stretch fabric portion forming a part of said fabric covering and located within an opening in said stretch-controlling fabric portion, said two-way stretch fabric portion forming a panel of between about 1.8-3.8 inches in width as measured radially between linear tangent points of said panel and said stretch-controlling fabric, said panel joined to said stretch-controlling fabric portion and located to overlie the knee joint of a residual leg when said liner is worn, said two-way stretch fabric portion comprised of a fabric having a range of elasticity of between about 100-130% in both directions and a 50% modulus of less than about 3.25 lbf.;   a layer of a cushioning block copolymer and mineral oil gel composition residing along only an interior of said fabric covering, said block copolymer and mineral oil gel composition extending from said closed end of said fabric covering at least a distance that is substantially equivalent to the depth of a prosthetic socket with which said covering will be used; and   a docking element located at the closed end of said fabric covering for attaching said liner to a socket portion of a prosthetic leg;   wherein said stretch-controlling fabric portion of said fabric covering is provided to limit longitudinal stretching of said liner while said two-way stretch fabric portion of said fabric covering is provided to permit adequate flexion of a knee joint of the amputee's residual leg.   
     
     
         30 . The liner of  claim 29 , wherein the closed end of said fabric covering is closed by said docking element. 
     
     
         31 . The liner of  claim 29 , wherein said block copolymer and mineral oil gel composition includes KEVLAR that reinforces said gel composition and assists with liner stretch control. 
     
     
         32 . The liner of  claim 29 , wherein a controlled-stretch portion of said liner exhibits an elasticity in a longitudinal direction of between about 15-25%, an elasticity in a circumferential direction of between about 90-130%, and has a 50% modulus in the circumferential direction of between about 1.0-2.0 lbf., and wherein said liner in the area of said panel of two-way stretch fabric exhibits an elasticity of 60% or greater in both the longitudinal and circumferential directions, and has a 50% modulus of between about 1.0-3.0 lbf.