Prosthesis with resilient ankle block

Abstract

An ankle block prosthesis is provided having a lower foot plate and an upper ankle plate connected by a monolithic ankle block. The foot plate, ankle plate and ankle block are generally sized to fit within a surrounding cosmesis. The foot is configured such that during a walking or running stride the wearer experiences a smooth rollover or transition of compressive forces from a heel-strike position to a toe-off position so as to provide a natural feeling foot during walking or running activities.

What is claimed is:  
     
         1 . A prosthetic foot for providing resilient kinematic support to an amputee, said prosthetic foot comprising: 
 a lower foot plate element having a length from toe to heel roughly equal to that of a natural human foot being replaced, said foot plate element being formed of a monolithic composite material having an area moment of inertia about a first axis that is substantially smaller than the area moment of inertia about a second axis perpendicular to said first axis such that said foot plate element is capable of flexing along its length in a fore-and-aft direction, but not substantially in a side-to-side direction, said foot plate element defining toe and heel portions of said prosthetic foot;    an upper ankle plate element having a length shorter than said foot plate element and being separately formed of a monolithic composite material having an area moment of inertia about a first axis that is substantially smaller than the area moment of inertia about a second axis perpendicular to said first axis such that said ankle plate element is capable of flexing along its length in a fore-and-aft direction, but not substantially in a side-to-side direction, said ankle plate element and said foot plate element being spaced apart from one another along their entire length;    an ankle block comprising a compressible material having a thickness of between about 0.83 inches and about 1.30 inches, said ankle block being positioned between said ankle plate element and said foot plate element; and    an attachment member secured to said ankle plate element adapted to attach said prosthetic foot to a pylon or socket, said attachment member defining an attachment axis located posteriorly along a longitudinal center line at a point approximately two-thirds of the distance rearward along the length of said ankle plate element;    said foot plate element, said ankle plate element and said ankle block cooperating such that as said amputee walks on said foot, compression stress migrates substantially uniformly through said ankle block such that substantially smooth rollover of said foot prosthesis is achieved.    
     
     
         2 . The prosthetic foot of  claim 1 , wherein said ankle block extends roughly said length of said ankle plate element.  
     
     
         3 . The prosthetic foot of  claim 1 , wherein said foot plate element comprises a resilient plate formed from a plurality of laminae embedded in a hardened flexible polymer material.  
     
     
         4 . The prosthetic foot of  claim 3 , wherein said ankle plate element comprises a resilient plate formed from a plurality of laminae embedded in a hardened flexible polymer material.  
     
     
         5 . The prosthetic foot of  claim 1 , wherein said ankle block comprises a monolithic block formed of a relatively compliant compressible material.  
     
     
         6 . The prosthetic foot of  claim 5 , wherein said ankle block is formed of a polyurethane material.  
     
     
         7 . The prosthetic foot of  claim 6 , wherein said ankle block is formed of a cellular polyurethane foam having a density of between about 25-35 lbs/ft 3 .  
     
     
         8 . The prosthetic foot of  claim 1 , wherein said ankle block comprises a monolithic block formed of a natural or synthetic rubber.  
     
     
         9 . A prosthetic foot, comprising: 
 a monolithic foot plate having toe and heel portions and a length from toe to heel roughly equal to that of a natural human foot being replaced, said foot plate comprising a resilient multi-laminate material capable of flexing substantially along its length;    an ankle plate having a length substantially shorter than said foot plate, said ankle plate being disposed substantially above and roughly parallel to said foot plate so as to define a space therebetween;    a resilient ankle block comprising a compressible material positioned between said ankle plate and said foot plate in said space formed between said foot plate and said ankle plate; and    an attachment member secured to said ankle plate adapted to attach said prosthetic foot to a pylon or other intermediate prosthetic device, said attachment member defining an attachment axis located posteriorly along a longitudinal center line at a point such that more of said resilient ankle block is disposed forward of the attachment axis than is disposed to the rear of the attachment axis;    said foot plate, said ankle plate and said ankle block cooperating such that as said amputee walks on said foot, compression stress migrates substantially uniformly through said ankle block so as to provide substantially smooth rollover of said prosthetic foot.    
     
     
         10 . The prosthetic foot of  claim 9 , wherein said attachment member defines an attachment axis located posteriorly along a longitudinal center line at a point approximately two-thirds of the distance rearward along the length of said ankle plate element.  
     
     
         11 . The prosthetic foot of  claim 9 , wherein said ankle block comprises a monolithic block formed of a relatively compliant compressible material.  
     
     
         12 . The prosthetic foot of  claim 11 , wherein said ankle block is formed of a polyurethane material.  
     
     
         13 . The prosthetic foot of  claim 12 , wherein said ankle block has a thickness of between about 0.83 inches and about 1.30 inches.  
     
     
         14 . The prosthetic foot of  claim 12 , wherein said ankle block is formed of a cellular polyurethane foam having a density of between about 25-35 lbs/ft 3 .  
     
     
         15 . The prosthetic foot of  claim 1 , wherein said ankle block comprises a monolithic block formed of a natural or synthetic rubber.  
     
     
         16 . A prosthetic foot, comprising: 
 a lower foot plate having a length and width approximately equal to that of a natural human foot being replaced, said foot plate having anterior and posterior ends and being constructed of a material capable of flexing along its length;    an upper ankle plate having a length shorter than said length of said foot plate, said ankle plate having anterior and posterior ends and being constructed of a material capable of flexing along its length, said foot plate and said ankle plate being disposed relative to one another so as to define a space therebetween;    an ankle block of compressible foam material bonded to an upper surface of said foot plate and to a lower surface of said ankle plate, said ankle plate being aligned with said ankle block and both being positioned rearward from a center of said foot plate; and    an attachment member secured to said ankle plate adapted to attach said prosthetic foot to a pylon or other intermediate prosthetic member, said attachment member defining an attachment axis located posteriorly along a longitudinal center line of said ankle plate and wherein said attachment member further comprises means for aligning said prosthetic foot relative to said pylon or socket and for transmitting torsional forces from said prosthetic foot to said pylon or socket.    
     
     
         17 . The prosthetic foot of  claim 16 , wherein said attachment member defines an attachment axis located posteriorly along a longitudinal center line at a point approximately two-thirds of the distance rearward along the length of said ankle plate element.  
     
     
         18 . The prosthetic foot of  claim 16 , wherein said ankle block comprises a monolithic block formed of a relatively compliant compressible material.  
     
     
         19 . The prosthetic foot of  claim 18 , wherein said ankle block is formed of a polyurethane material.  
     
     
         20 . The prosthetic foot of  claim 19 , wherein said ankle block has a thickness of between about 0.83 inches and about 1.30 inches.  
     
     
         21 . A prosthetic foot for replacing a natural human foot, said prosthetic foot comprising: 
 an elongated lower foot plate element having a length and width roughly equal to that of said natural human foot being replaced, said foot plate element having top and bottom surfaces and being formed of a resilient material having an area moment of inertia about a first axis that is substantially smaller than the area moment of inertia about a second axis perpendicular to said first axis such that said foot plate element is capable of flexing along its length in a first direction but not substantially in a second direction;    an elongated upper ankle plate element having a length shorter than said foot plate element, said upper ankle plate element having top and bottom surfaces and being formed of a resilient material having an area moment of inertia about a first axis that is substantially smaller than the area moment of inertia about a second axis perpendicular to said first axis such that said ankle plate element is capable of flexing along its length in a first direction, but not substantially in a second direction;    an elongated monolithic block of compressible material having a top surface and a bottom surface, the bottom surface of said monolithic block being bonded to the top surface of said foot plate element such that they are substantially aligned along their respective axes of elongation, the top surface of said monolithic block being bonded to the bottom surface of said ankle plate element such that they are substantially aligned along their respective axes of elongation; and    an attachment member secured to said ankle plate element adapted to attach said prosthetic foot to a pylon or other intermediate prosthetic member, said attachment member defining an attachment axis located posteriorly along a longitudinal center line at a point approximately two-thirds of the distance rearward along the length of said ankle plate element.    
     
     
         22 . The prosthetic foot of  claim 21  further comprising a sole cushion secured to said bottom surface of said foot plate element.  
     
     
         23 . The prosthetic foot of  claim 21 , wherein said ankle block comprises a single monolithic block of material having sufficient strength and resiliency such that it is capable of supporting substantially the entire weight of an amputee wearing said prosthetic foot while allowing substantially uniform migration of stress through said ankle block in response to flexing of said flexible plate members.  
     
     
         24 . The prosthetic foot of  claim 23 , wherein said ankle block comprises a monolithic block formed of a polyurethane material.  
     
     
         25 . The prosthetic foot of  claim 23 , wherein said ankle block has a thickness of between about 0.83 inches and about 1.30 inches.  
     
     
         26 . The prosthetic foot of  claim 23 , wherein said ankle block is formed of a cellular polyurethane foam having a density of between about 25-35 lbs/ft 3 .  
     
     
         27 . The prosthetic foot of  claim 23 , wherein said ankle block comprises a monolithic block formed of a natural or synthetic rubber.  
     
     
         28 . A prosthetic foot for replacing a natural human foot, said prosthetic foot comprising: 
 a lower plate element having a length and width roughly equal to that of said natural human foot being replaced and having top and bottom surfaces, said lower plate element being formed of a monolithic composite material capable of flexing substantially along its length and having an area moment of inertia about a first axis that is substantially smaller than the area moment of inertia about a second axis perpendicular to said first axis such that said lower plate element is capable of flexing along its length in a first direction but not substantially in a second direction;    an upper plate element having a length shorter than said lower plate element and having top and bottom surfaces, said upper plate element being formed of a monolithic composite material and having an area moment of inertia about a first axis that is substantially smaller than the area moment of inertia about a second axis perpendicular to said first axis such that said upper plate element is capable of flexing along its length in a first direction, but not substantially in a second direction;    a resilient ankle member composed of a compressible material sandwiched between said lower plate element and said upper plate element, said ankle member comprising a top surface and a bottom surface, the bottom surface of said ankle member being matingly bonded to the top surface of said lower plate element, the top surface of said ankle member being matingly bonded to the bottom surface of said upper plate element, such that said lower and upper plate elements and said ankle member are thereby maintained in intimate cooperative contact with one another along their respective mating surfaces; and    an attachment member secured to said upper plate element adapted to attach said prosthetic foot to a pylon or other intermediate prosthetic member, said attachment member defining an attachment axis located along a longitudinal center line of said prosthetic foot at a point such that more of said ankle member is disposed forward of the attachment axis than is disposed rearward of the attachment axis.    
     
     
         29 . The prosthetic foot of  claim 28 , wherein said lower plate element comprises a toe end and an uplifted heel end and an intermediate region therebetween.  
     
     
         30 . The prosthetic foot of  claim 29 , wherein said lower plate element is tapered along at least a portion of its length so as to provide desired bending and energy storage characteristics.  
     
     
         31 . The prosthetic foot of  claim 30 , wherein said lower plate element is tapered from a relatively thick portion proximal said intermediate region to relatively thin portions proximal said heel and toe ends.  
     
     
         32 . The prosthetic foot of  claim 28 , wherein said attachment member comprises a base plate adapted to be fastened to an upper surface of the upper plate element and an upstanding coupling knob formed integrally therewith for securing said prosthetic foot to a pylon or other prosthetic member intermediate said prosthetic foot and the stump of an amputee.  
     
     
         33 . The prosthetic foot of  claim 28 , wherein said ankle member comprises a single monolithic block of material having sufficient strength and resiliency such that it is capable of supporting substantially the entire weight of an amputee wearing said prosthetic foot while allowing substantially uniform migration of stress through said ankle member in response to flexing of said upper and lower plate elements.  
     
     
         34 . The prosthetic foot of  claim 28 , wherein said ankle member comprises a monolithic block formed of a polyurethane material.  
     
     
         35 . The prosthetic foot of  claim 28 , wherein said ankle member has a thickness of between about 0.83 inches and about 1.30 inches.  
     
     
         36 . The prosthetic foot of  claim 28 , wherein said ankle member comprises a monolithic block formed of a natural or synthetic rubber.