Prosthetic knee joint

• US 4,005,496 A
• Filed: 06/13/1975
• Issued: 02/01/1977
• Est. Priority Date: 06/28/1974
• Status: Expired due to Term

• Current Assignee: Hosmer-Dorrance Corp. (Fillauer Cos, Inc.)
• Original Assignee: Hosmer-Dorrance Corp. (Fillauer Cos, Inc.)
• Inventors: Wilkes, Donald F.
• Primary Examiner(s): Frinks, Ronald L.
• Application Number:
  US05/586,544
• Time in Patent Office: 599 Days
• Field of Search: 3/22-29, 3/2, 3/1.2, 3/21
• US Class Current: 623/44
• CPC Class Codes: A61F 2/64 Knee joints
• CPC Class Codes: A61F 2/642 Polycentric joints, without longitudinal rotation
• CPC Class Codes: A61F 2002/5067 having rolling elements between articulating surfaces for implantable joints A61F2002/30639
• CPC Class Codes: A61F 2002/5073 Helical springs, e.g. having at least one helical spring

Abstract

A prosthetic knee joint having a femoral member and a tibial member each of which is provided with a bearing surface. The bearing surface of the tibial member supports the bearing surface associated with the femoral member such that flexion between the tibial member and the femoral member causes the respective bearing surfaces to roll relative to one another. Rollers, cam surfaces and guide slots are provided to ensure the retention of the proper relationship for this rolling contact between the tibial bearing surface and the femoral bearing surface. The knee joint includes a mechanical brake which produces a brake force that increased with flexure between the tibial member and the femoral member. The brake includes a resilient deformable element which transmits a brake applying force to a brake shoe which is operable along an axis generally perpendicular to the direction in which the force is applied. Hyperextension of the knee joint is mechanically limited and a torsion rod accommodates torsional motion between the knee joint and a lower leg to which it may be attached. The knee joint also includes a member which simulates the movement of the patella bone of a human knee.

Claims

1. A prosthetic knee joint for an artificial leg comprising:

a tibial member having at least one tibial bearing surface, said at least one tibial bearing surface having a first arcuate configuration,

a femoral member being movable relative to said tibial member and having at least one femoral bearing surface, said at least one tibial bearing surface having a second arcuate configuration supportingly engaging said at least one femoral bearing surface;

rolling contact means for establishing rolling contact between said at least one femoral bearing surface and said at least one tibial bearing surface substantially along the entire length of said tibial bearing surface while preventing substantial sliding movement between said tibial bearing surface and said femoral bearing surface; and

engagement means for preventing disengagement of said at least one femoral bearing surface and said at least one tibial surface during rolling movement therebetween.

2. The prosthetic knee joint of claim 1 wherein said tibial bearing surface is concave and wherein said femoral bearing surface is convex.

3. The prosthetic knee joint of claim 2 wherein the radius of curvature of the tibial bearing surface is twice the radius of curvature of the femoral bearing surface.

4. The prosthetic knee joint of claim 1 wherein said rolling contact means includes:

guiding roller means for positioning said femoral bearing surface and said tibial bearing surface relative to one another, said guiding roller means projecting laterally from said femoral member; and

slot means on said tibial member for receiving said guiding roller means, said slot means having cam surfaces against which said guiding roller means is guided such that said guiding roller means and said slot means cooperate to substantially eliminate sliding motion between said femoral bearing surface and said tibial bearing surface.

5. The prosthetic knee joint of claim 1 wherein said engagement means includes:

retaining roller means for inhibiting separation of said femoral and tibial bearing surfaces, said retaining roller means projecting laterally from said femoral member; and

cam surface means for cooperating with said retaining roller means to inhibit bearing surface separation, said cam surface means carried by said tibial member and having a contour configured to constrain the retaining roller means to the trajectory defined by rolling contact between the bearing surfaces.

6. The prosthetic knee joint of claim 4 including:

pivot roller means for permitting simple pivotal motion between said femoral member and said tibial member, said pivot roller means projects laterally from said femoral member and moves freely within said slot means during rolling motion between said femoral and tibial bearing surfaces;

said slot means includes a socket for receiving said pivot roller means at the posterior end of said rolling motion and an arcuate surface for constraining movement of said guiding roller to a circular arc throughout said pivotal motion; and

said guiding roller means cooperating with said arcuate surface to retain said pivot roller in said socket.

7. In a prosthetic knee joint having a femoral member and a tibial member mounted for relative movement wherein the improvement comprises:

means for simulating a patella, said means for simulating pivotally connected to said femoral member and pivotally connected to said tibial member and said means for simulating a patella includes

at least one patellar member pivotally connected to said tibial member, and

at least one patellar link having one end pivotally connected to said femoral member and another end pivotally connected to said patellar member, whereby said at least one patellar member moves in response to relative movement between said femoral member and said tibial member.

8. In a prosthetic knee joint having a femoral member and a tibial member mounted for relative movement wherein the improvement comprises:

means for simulating a patella, said means for simulating pivotally connected to said femoral member and pivotally connected to said tibial member;

at least one patellar member pivotally connected to said tibial member;

at least one patellar link having one end pivotally connected to said femoral member and another end pivotally connected to said patellar member, whereby said at least one patellar member moves in response to relative movement between said femoral member and said tibial member;

wherein said at least one patellar member is pivotally connected to an anterior portion of said tibial member; and

wherein said at least one patellar link is pivotally connected to a posterior portion of said femoral member.

9. A prosthetic knee joint having a pair of relatively movable members wherein the improvement comprises:

a brake drum provided for one of said pair of members and having opposed braking surfaces;

resilient brake shoe means carried by the second of said pair of members and having a longitudinal member with spaced ends positioned adjacent the braking surfaces, the longitudinal member being operable to increase spacing between said ends in response to a transverse squeezing force so that the resilient brake shoe means is operable to frictionally engage said brake drum;

means for selectively applying a transverse squeezing force to said longitudinal member, said means for applying force carried by the second of said pair of members,

whereby said resilient brake shoe means engages said brake drum to resist relative movement between said pair of relatively movable members.

10. The knee joint of claim 9 wherein:

said longitudinal member is a deformable resilient element having at least one brake shoe connected to at least one end of said deformable resilient element; and

wherein said means for selectively applying force selectively engages said deformable resilient element which transmits a related force to said at least one brake shoe.

11. The knee joint of claim 10 wherein:

said force applying means includes a lever pivotally mounted on the second of said pair of members and a plunger having two ends, one end being operatively connected to said lever and the second end engaging said deformable resilient element.

12. A prosthetic knee joint having a pair of relatively movable members wherein the improvement comprises:

a brake drum provided for one of said pair of members;

brake shoe means for frictionally engaging said brake drum, said brake shoe means carried by the second of said pair of members;

means for selectively applying force to said brake shoe means, said means for applying force carried by the second of said pair of members;

whereby said brake shoe means engages said brake drum to resist relative movement between said pair of relatively movable members;

wherein said brake shoe means includes a deformable resilient element having at least one end and having at least one brake shoe connected to said at least one end of said deformable resilient element;

wherein said means for selectively applying force selectively engages said deformable resilient element which transmits an applied force to said at least one brake shoe;

said at least one brake shoe fabricated from brake shoe material; and

said deformable resilient element disposed within a cylindrical member having an opening in the cylindrical surface thereof to receive said plunger.

13. A proportional brake for a prosthetic knee joint comprising:

a prosthetic knee joint which includes a pair of relatively movable members that contact one another at a pivot axis, said pivot axis moving posteriorly of said knee joint when said knee joint is flexed and moving anteriorly of said knee joint when said knee joint is extended;

brake means for resisting flexure of said knee joint, said brake means connected to said knee joint anteriorly thereof; and

means for selectively operating said brake means, said means for selectively operating being carried by one of said pair of relatively movable members,

whereby a force moment tending to flex said prosthetic knee joint is resisted by a braking force moment which increases with flexure of said knee joint due to posterior movement of said pivot axis away from said anteriorly positioned brake means.

14. The proportional brake of claim 13 wherein said brake means includes:

a brake drum provided anteriorly of one of said pair of relatively movable members;

brake shoe means for frictionally engaging said brake drum, said brake shoe means anteriorly carried by the second of said pair of relatively movable members; and

means for selectively applying force to said brake shoe means, said means for applying force carried by the second of said pair of relatively movable members.

15. The proportional brake of claim 14:

wherein said brake shoe means includes a deformable resilient element having at least one end and having at least one brake shoe connected to said at least one end of said deformable resilient element; and

wherein said means for selectively applying force selectively engages said deformable resilient element which transmits an applied force to said at least one brake shoe.

16. The proportional brake of claim 15:

wherein said force applying means includes a lever pivotally mounted on the second of said pair of members and a plunger having two ends, one end being operatively connected to said lever and the second end engaging said deformable resilient element.

17. A proportional brake of claim 16 including:

said at least one brake shoe being fabricated from brake shoe material; and

said deformable resilient element being disposed within a cylindrical member having an opening in the cylindrical surface thereof to receive said plunger.

18. A prosthetic knee joint for an artificial leg comprising:

a tibial member having at least one tibial bearing surface, said at least one tibial bearing surface having a first arcuate configuration;

a femoral member being movable relative to said tibial member and having at least one femoral bearing surface, said at least one femoral bearing surface having a second arcuate configuration, said at least one tibial bearing surface supportingly engaging said at least one femoral bearing surface;

a first means for establishing rolling contact between said at least one femoral bearing surface and said at least one tibial bearing surface substantially along the length of each said bearing surface;

a second means for preventing disengagement of said at least one femoral bearing surface and said at least one tibial bearing surface;

means for simulating a patella, said means for simulating being connected to said femoral member and to said tibial member;

brake means for resisting relative movement between said tibial member and said femoral member, said brake means attached anteriorly to said tibial member and said femoral member; and

means for selectively operating said brake means, said means for selectively operating carried by said femoral member.

19. In a prosthetic leg for an above-knee amputee having a femoral member operable for attachment to the amputee'"'"'s thigh for pivotal movement about a point generally coinciding with the amputee'"'"'s hip joint, a tibial member with pivotal movement about a prosthetic ankle, a distance defined between said point and said prosthetic ankle, and an angle defined between said femoral member and said tibial member, wherein the improvement comprises:

femoral bearing surface having a first contour;

a tibial bearing surface having a second contour which contacts said femoral bearing surface such that said first contour touches said second contour at an instantaneous axis of rotation;

said angle having a first predetermined value when said femoral member and said tibial member are aligned such that said distance has a first minimum value; and

said first contour and said second contour cooperate to increase said distance when said angle increases, said instantaneous axis of rotation movable posteriorly when said angle increases;

whereby a toggle action is effected to generate stability about said first predetermined value.

20. The prosthetic leg of claim 19 wherein:

said first contour and said second contour cooperate to function as a simple pivot joint when said angle increases above a predetermined angle.

21. A method of walking with a prosthetic knee joint comprising the steps of:

flexing the knee joint with a first range defined between a first predetermined angle and a second predetermined angle which exceeds the first predetermined angle, thereby raising a hip joint of an amputee;

flexing the knee joint within a second range defined between the second predetermined angle and a third predetermined angle which exceeds the second predetermined angle, thereby lowering the hip joint; and

flexing said knee joint through the second range in which the articulation angle exceeds said second predetermined value, thereby establishing a hinged movement.

22. The method of walking of claim 21 wherein:

said flexing within said first range occurs while striking a supporting surface with a prosthetic foot attached below the prosthetic knee joint.

23. The method of walking of claim 22 including the step of:

braking the knee joint against further flexure while in said first range.

24. A prosthetic joint connecting members for relative movement, said joint comprising:

an upper member having means for attachment to an amputee;

a lower member having a prosthetic member connected thereto;

means for swinging lower member relative to said upper member; and

means for rotating said lower member about its longitudinal axis relative to said upper member, being positioned between said lower member and said means for swinging, and having a torsion rod connected at one end to said means for swinging and connected at the other end to said lower member.

25. The prosthetic joint according to claim 24 wherein said means for swinging includes a base, and said means for rotating includes a rotary bearing interposed between said base and said lower member, said bearing being arranged to allow rotation of said base about said longitudinal axis of said lower member, said means for rotating includes means for yieldably resisting rotation of said one member about said longitudinal axis from a predetermined rotational position.

26. The prosthetic joint according to claim 25 wherein said means for rotating includes a torsion rod extending along said longitudinal axis, said rod being secured to said base at a first location on said rod and being secured to said one member at a second location on said rod, said first and second locations being spaced longitudinally along said rod, whereby said rod yieldably resists rotation of said base relative to said one member from a predetermined rotational position.

27. The prosthetic joint according to claim 25 wherein said rotary bearing is a ball bearing and contains grease to dampen torsional motion, and wherein said base and said lower member include stop means to limit rotation relative to each other about said longitudinal axis.

28. A prosthetic knee joint comprising:

a tibial member having at least one tibial bearing surface, said at least one tibial bearing surface having a first arcuate configuration,

a femoral member being movable relative to said tibial member and having at least one femoral bearing surface, said at least one femoral bearing surface having a second arcuate configuration, said at least one tibial bearing surface supportingly engaging said at least one femoral bearing surface;

rolling contact means for establishing rolling contact between said at least one femoral bearing surface and said at least one tibial surface; and

engagement means for preventing disengagement of said at least one femoral bearing surface and said at least one tibial bearing surface,

said engagement means including a pin connected to one of said tibial member and said femoral member, and

the other of said tibial member and said femoral member being provided with a slot for receiving said pin while allowing said pin to move during articulation of the prosthetic knee joint.

29. The prosthetic knee joint of claim 28 further including:

a hinge pin positioned at the posterior end of one of said femoral bearing surface and said tibial bearing surface; and

the other of said femoral bearing surface and said tibial bearing surface being provided with a hinge pin receiving socket which cooperates with said hinge pin to permit pivotal movement between said tibial member and said femoral member at the end of rolling contact therebetween.

30. A prosthetic knee joint comprising:

a femoral member having a convex femoral bearing surface and a generally planar upper surface;

a tibial member having a concave tibial bearing surface and a generally planar lower surface;

hypocycloidal means for establishing hypocyloidal motion between said femoral bearing surface and said tibial bearing surface throughout a first range of articulation angles where the articulation angle is defined as one of the intersecting angles between a line normal to the upper surface and a line normal to the lower surface; and

pivot means for establishing pivotal motion between said femoral member and said tibial member throughout a second range of articulation angles.

31. The prosthetic knee joint of claim 30 wherein:

the convex femoral bearing surface has a center of curvature; and

the hypocycloidal means includes

a retaining roller extending laterally from the femoral member and having an axis coincident with the center of curvature;

a guiding roller extending laterally from the femoral member in juxtaposition to the femoral bearing surface and centrally positioned with respect to the arcuate femoral bearing surface,

cam surface means carried by the tibial member, positioned above the tibial bearing surface, for cooperation with the retaining roller to maintain contact between the tibial bearing surface and the femoral bearing surface, and

guide slot means positioned on the tibial member between the cam surface and the tibial bearing surface for cooperating with the guiding roller to constrain movement between the tibial bearing surface and the femoral bearing surface to substantially hypocycloidal motion.

32. The prosthetic knee joint of claim 31 wherein:

the pivot means includes a pivot roller extending laterally from the femoral member into the guide slot means; and

the guide slot means includes

a socket portion in which the pivot roller is received to effect transition from the first range of articulation angles to the second range of articulation angles, and

an arcuate surface against which the guiding roller moves during the second range of articulation angles to prevent the pivot roller from leaving the socket portion.

33. The prosthetic knee joint of claim 32 further including:

patella means pivotally connected to the femoral member and to the tibial member and having an abutment surface on the patella means to define a limit for the second range of articulation angles.

34. The prosthetic knee joint of claim 32 wherein the pivot means includes:

a pivot roller extending laterally from the femoral member;

guide slot means extending upwardly from the tibial member for receiving the pivot roller throughout the first range of articulation angles and having a socket portion for receiving the pivot roller during the second range of articulation angles; and

means for retaining the pivot roller in the socket portion throughout the second range of articulation angles.