Prosthetic foot with tunable performance

A prosthetic foot comprising:

• a longitudinally extending foot keel having a forefoot portion at one end, a hindfoot portion at an opposite end and a relatively long midfoot portion extending between and upwardly arched from said forefoot and hindfoot portions;
• a releasable fastener;
• an upstanding calf shank including a downward convexly curved lower end which is attached at a portion thereof to a proximate, posterior surface of said keel midfoot portion by way of said releasable fastener;
• and
• means for adjusting the alignment of said calf shank and said foot keel with respect to one another in the longitudinal direction of said foot keel for tuning the performance of said prosthetic foot to be task specific;
• wherein said means for adjusting the alignment includes a longitudinally extending opening in at least one of said proximate, posterior surface of said keel midfoot portion and said downward convexly curved lower end of said calf shank, said releasable fastener extending through said opening to permit adjustably attaching said calf shank to said foot keel for adjusting said alignment.

A prosthetic foot comprising:

• a longitudinally extending foot keel having a forefoot portion at one end, a hindfoot portion at an opposite end and a relatively long midfoot portion extending between and upwardly arched from said forefoot and hindfoot portions;
• a releasable fastener;
• an upstanding calf shank including a downward convexly curved lower end which is attached at a portion thereof to a proximate, posterior surface of said keel midfoot portion by way of said releasable fastener;
• and
• means for adjusting the alignment of said calf shank and said foot keel with respect to one another in the longitudinal direction of said foot keel for tuning the performance of said prosthetic foot to be task specific;
• wherein said curved lower end of said calf shank is in the shape of a parabola with the smallest radius of curvature of said parabola located at said lower end and extending upwardly in said parabola shape.

A prosthetic foot comprising:

• a longitudinally extending foot keel having a forefoot portion at one end, a hindfoot portion at an opposite end and a relatively long midfoot portion extending between and upwardly arched from said forefoot and hindfoot portions;
• a releasable fastener;
• an upstanding calf shank including a downward convexly curved lower end which is attached at a portion thereof to a proximate, posterior surface of said keel midfoot portion by way of said releasable fastener;
• and
• means for adjusting the alignment of said calf shank and said foot keel with respect to one another in the longitudinal direction of said foot keel for tuning the performance of said prosthetic foot to be task specific;
• wherein said convexly curved lower end of said calf shank extends upward anteriorly from said lower end.

A prosthetic foot comprising:

• a longitudinally extending foot keel having a forefoot portion at one end, a hindfoot portion at an opposite end and a relatively long midfoot portion extending between and upwardly arched from said forefoot and hindfoot portions;
• a releasable fastener;
• an upstanding calf shank including a downward convexly curved lower end which is attached at a portion thereof to a proximate, posterior surface of said keel midfoot portion by way of said releasable fastener;
• and
• means for adjusting the alignment of said calf shank and said foot keel with respect to one another in the longitudinal direction of said foot keel for tuning the performance of said prosthetic foot to be task specific;
• wherein said hindfoot portion includes a heel with a posterior lateral corner which is more posterior and lateral than the medial corner of the heel to encourage hindfoot eversion during initial contact phase of gait.

A prosthetic foot comprising:

• a longitudinally extending foot keel having a forefoot portion at one end, a hindfoot portion at an opposite end and a relatively long midfoot portion extending between and upwardly arched from said forefoot and hindfoot portions;
• a releasable fastener;
• an upstanding calf shank including a downward convexly curved lower end which is attached at a portion thereof to a proximate, posterior surface of said keel midfoot portion by way of said releasable fastener;
• and
• means for adjusting the alignment of said calf shank and said foot keel with respect to one another in the longitudinal direction of said foot keel for tuning the performance of said prosthetic foot to be task specific;
• wherein a dorsal aspect of said midfoot portion and forefoot portion of said foot keel is formed with an upwardly facing concavity which mimics in function the fifth ray axis of motion of a human foot, said concavity having a longitudinal axis which is oriented at an angle of 20° to 35° to the longitudinal axis of the foot keel with the medial being more anterior than the lateral to encourage fifth ray motion in gait as in the oblique low gear axis of rotation of the second to fifth metatarsals in the human foot.

A prosthetic foot comprising:

• a longitudinally extending foot keel having a forefoot portion at one end, a hindfoot portion at an opposite end and a relatively long midfoot portion extending between and upwardly arched from said forefoot and hindfoot portions;
• a releasable fastener;
• an upstanding calf shank including a downward convexly curved lower end which is attached at a portion thereof to a proximate, posterior surface of said keel midfoot portion by way of said releasable fastener;
• and
• means for adjusting the alignment of said calf shank and said foot keel with respect to one another in the longitudinal direction of said foot keel for tuning the performance of said prosthetic foot to be task specific;
• wherein the posterior of the forefoot portion of said keel includes medial and lateral expansion joint holes extending through said forefoot portion between dorsal and plantar surfaces thereof, and expansion joints extending forward from respective ones of said holes to the anterior edge of the forefoot portion to form medial, middle and lateral expansion struts which create improved biplanar motion capability of the forefoot portion of said foot keel;
• and
• wherein said expansion joint holes are located along a line in the transverse plane which extends at an angle of 25 to 35° to the longitudinal axis of the foot keel with the medial expansion joint hole more anterior than the lateral expansion joint hole.

A prosthetic foot comprising:

• a longitudinally extending foot keel having a forefoot portion at one end, a hindfoot portion at an opposite end and a relatively long midfoot portion extending between and upwardly arched from said forefoot and hindfoot portions;
• a releasable fastener;
• an upstanding calf shank including a downward convexly curved lower end which is attached at a portion thereof to a proximate, posterior surface of said keel midfoot portion by way of said releasable fastener;
• and
• means for adjusting the alignment of said calf shank and said foot keel with respect to one another in the longitudinal direction of said foot keel for tuning the performance of said prosthetic foot to be task specific;
• wherein the posterior of the forefoot portion of said keel includes medial and lateral expansion joint holes extending through said forefoot portion between dorsal and plantar surfaces thereof, and expansion joints extending forward from respective ones of said holes to the anterior edge of the forefoot portion to form medial, middle and lateral expansion struts which create improved biplanar motion capability of the forefoot portion of said foot keel;
• and
• wherein said expansion joint holes as projected on a sagittal plane are inclined at an angle of 45° to the transverse plane with the dorsal aspect of the holes being more anterior than the plantar aspect.

A prosthetic foot comprising:

• a longitudinally extending foot keel having a forefoot portion at one end, a hindfoot portion at an opposite end and a relatively long midfoot portion extending between and upwardly arched from said forefoot and hindfoot portions;
• a releasable fastener;
• an upstanding calf shank including a downward convexly curved lower end which is attached at a portion thereof to a proximate, posterior surface of said keel midfoot portion by way of said releasable fastener;
• and
• means for adjusting the alignment of said calf shank and said foot keel with respect to one another in the longitudinal direction of said foot keel for tuning the performance of said prosthetic foot to be task specific;
• wherein the posterior of the forefoot portion of said keel includes medial and lateral expansion joint holes extending through said forefoot portion between dorsal and plantar surfaces thereof, and expansion joints extending forward from respective ones of said holes to the anterior edge of the forefoot portion to form medial, middle and lateral expansion struts which create improved biplanar motion capability of the forefoot portion of said foot keel;
• and
• wherein the distance from the releasable fastener to the lateral expansion joint hole is shorter than the distance from the releasable fastener to the medial expansion joint hole such that the lateral portion of the prosthetic foot has a shorter toe lever than the medial for enabling midfoot high and low dynamic response.

A prosthetic foot comprising:

• a longitudinally extending foot keel having a forefoot portion at one end, a hindfoot portion at an opposite end and a relatively long midfoot portion extending between and upwardly arched from said forefoot and hindfoot portions;
• a releasable fastener;
• an upstanding calf shank including a downward convexly curved lower end which is attached at a portion thereof to a proximate, posterior surface of said keel midfoot portion by way of said releasable fastener;
• and
• means for adjusting the alignment of said calf shank and said foot keel with respect to one another in the longitudinal direction of said foot keel for tuning the performance of said prosthetic foot to be task specific;
• wherein said midfoot portion is formed of a semi-rigid material with a longitudinal arch shaped to create a dynamic response capability of said foot in gait such that the medial aspect of the longitudinal arch has a relatively higher dynamic response capability and the lateral aspect of said longitudinal arch has a relatively lower dynamic response capability.

A prosthetic foot comprising:

• a longitudinally extending foot keel having a forefoot portion at one end, a hindfoot portion at an opposite end and a relatively long midfoot portion extending between and upwardly arched from said forefoot and hindfoot portions;
• a calf shank including a downward, anteriorly facing convexly curved lower end;
• and
• an adjustable fastening arrangement attaching said curved lower end of said calf shank to said foot keel to form an ankle joint area of said prosthetic foot;
• and
• wherein said adjustable fastening arrangement permits adjustment of the alignment of said calf shank and said foot keel with respect to one another in the longitudinal direction of said foot keel for tuning the performance of said prosthetic foot.

A prosthetic foot comprising:

• a longitudinally extending foot keel having a forefoot portion at one end, a hindfoot portion at an opposite end and a relatively long midfoot portion extending between and upwardly arched from said forefoot and hindfoot portions;
• a calf shank including a downward convexly curved lower end;
• and
• an adjustable fastening arrangement attaching said curved lower end of said calf shank to said midfoot portion of said keel to form an ankle joint area of said prosthetic foot;
• and
• wherein said adjustable fastening arrangement permits adjustment of the alignment of said calf shank and said foot keel with respect to one another in the longitudinal direction of said foot keel for tuning the performance of said prosthetic foot;
• wherein said adjustable fastening arrangement includes at least one releasable fastener and a coupling element located between said calf shank and said keel, said coupling element and said at least one releasable fastener attaching said calf shank to said foot keel.

A prosthetic foot comprising:

• a longitudinally extending foot keel having a forefoot portion at one end, a hindfoot portion at an opposite end and a relatively long midfoot portion extending between and upwardly arched from said forefoot and hindfoot portions;
• a calf shank including a downward convexly curved lower end;
• and
• an adjustable fastening arrangement attaching said curved lower end of said calf shank to said midfoot portion of said keel to form an ankle joint area of said prosthetic foot;
• wherein said adjustable fastening arrangement permits adjustment of the alignment of said calf shank and said foot keel with respect to one another in the longitudinal direction of said foot keel for tuning the performance of said prosthetic foot;
• and
• wherein said convexly curved lower end of said calf shank extends upward anteriorly from said lower end.

A prosthetic foot comprising:

• a longitudinally extending foot keel having a forefoot portion at one end, a hindfoot portion at an opposite end and a relatively long midfoot portion extending between and upwardly arched from said forefoot and hindfoot portions;
• and
• an upstanding calf shank including a downward, anteriorly facing convexly curved lower end which is attached to said foot keel;
• wherein the calf shank and foot keel have respective, facing, convexly curved surfaces whose radii and relationship affect a dynamic response capability and motion outcome of the prosthetic foot in gait in a direction having anterior horizontal and vertical components.