Prosthetic components with partially contained compressible resilient members

• US 7,066,958 B2
• Filed: 05/09/2003
• Issued: 06/27/2006
• Est. Priority Date: 05/10/2002
• Status: Expired due to Fees

• Current Assignee: Bret A. Ferree
• Original Assignee: Bret A. Ferree
• Inventors: Ferree, Bret A.
• Primary Examiner(s): Snow, Bruce E.
• Application Number:
  US10/434,930
• Publication Number:
  US 20040024460A1
• Time in Patent Office: 1,145 Days
• Field of Search: 623/17.11, 623/17.12, 623/17.13, 623/17.14, 623/17.15, 623/17.16
• US Class Current: 623/17.12
• CPC Class Codes: A61B 17/86 Pins or screws or threaded wires; nuts therefor A61B17/72 take precedence
• CPC Class Codes: A61F 2/30742 Bellows or hose-like seals; Sealing membranes A61B17/8808 takes precedence; sealing membranes for retaining bone substitute A61F2/2846
• CPC Class Codes: A61F 2/32 for the hip
• CPC Class Codes: A61F 2/34 Acetabular cups
• CPC Class Codes: A61F 2/38 for elbows or knees
• CPC Class Codes: A61F 2/441 made of inflatable pockets or chambers filled with fluid, e.g. with hydrogel
• CPC Class Codes: A61F 2/4425 made of articulated components
• CPC Class Codes: A61F 2002/30069 elastomeric
• CPC Class Codes: A61F 2002/30075 swellable, e.g. when wetted
• CPC Class Codes: A61F 2002/30092 using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2002/30125 elliptical or oval
• CPC Class Codes: A61F 2002/30133 kidney-shaped or bean-shaped
• CPC Class Codes: A61F 2002/302 toroidal, e.g. rings
• CPC Class Codes: A61F 2002/30245 Partial spheres
• CPC Class Codes: A61F 2002/30364 Rotation about the common longitudinal axis
• CPC Class Codes: A61F 2002/30372 with additional means for limiting said translation
• CPC Class Codes: A61F 2002/30405 made by screwing complementary threads machined on the parts themselves
• CPC Class Codes: A61F 2002/30433 using additional screws, bolts, dowels, rivets or washers e.g. connecting screws
• CPC Class Codes: A61F 2002/30517 using a locking plate
• CPC Class Codes: A61F 2002/30528 Means for limiting said movement
• CPC Class Codes: A61F 2002/30563 : having elastic means or damping means, different from springs, e.g. including an elastomeric core or shock absorbers
• CPC Class Codes: A61F 2002/30566 : Helical springs
• CPC Class Codes: A61F 2002/30568 : Multiple spring systems including two or more helical springs
• CPC Class Codes: A61F 2002/30578 : having apertures, e.g. for receiving fixation screws
• CPC Class Codes: A61F 2002/30649 : Ball-and-socket joints
• CPC Class Codes: A61F 2002/30673 : Lubricating means, e.g. synovial pocket
• CPC Class Codes: A61F 2002/30878 : with non-sharp protrusions, for instance contacting the bone for anchoring, e.g. keels, pegs, pins, posts, shanks, stems, struts
• CPC Class Codes: A61F 2002/3401 : with radial apertures, e.g. radial bores for receiving fixation screws
• CPC Class Codes: A61F 2002/3429 : with an integral peripheral collar or flange, e.g. oriented away from the shell centre line
• CPC Class Codes: A61F 2002/3448 : Multiple cups made of three or more concentric shells fitted or nested into one another
• CPC Class Codes: A61F 2002/3493 : Spherical shell significantly greater than a hemisphere, e.g. extending over more than 200 degrees
• CPC Class Codes: A61F 2002/3611 : Heads or epiphyseal parts of femur
• CPC Class Codes: A61F 2002/443 : having two transversal endplates and at least one intermediate component
• CPC Class Codes: A61F 2002/448 : comprising multiple adjacent spinal implants within the same intervertebral space or within the same vertebra, e.g. comprising two adjacent spinal implants
• CPC Class Codes: A61F 2210/0014 : using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2210/0061 : swellable
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0033 : made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2220/0041 : using additional screws, bolts, dowels or rivets, e.g. connecting screws
• CPC Class Codes: A61F 2230/0008 : elliptical or oval
• CPC Class Codes: A61F 2230/0015 : Kidney-shaped, e.g. bean-shaped
• CPC Class Codes: A61F 2230/0065 : toroidal, e.g. ring-shaped, doughnut-shaped
• CPC Class Codes: A61F 2230/0071 : spherical
• CPC Class Codes: A61F 2310/00017 : Iron- or Fe-based alloys, e.g. stainless steel
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00029 : Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium
• CPC Class Codes: A61F 2310/00179 : Ceramics or ceramic-like structures

Abstract

One or more rigid components associated with an articulating bone are used to encase, encapsulate, contain, or otherwise protect a compressible/resilient member. The embodiments are applicable not only to artificial disc replacement (ADR) devices, but also to joint situations including total knee and hip arthroplasty. The cushion elements in the preferred embodiments include synthetic rubbers, hydrogels, elastomers, and other polymeric materials such as viscoelastic polymers and foam polyurethanes. The invention effectively combines the advantages of such materials (cushioning, shape memory, and expansion after insertion in the case of hydrogels), while providing increased protection, particularly the elimination of shear stresses. When applied to an ADR, the invention also minimizes the risk of extrusion.

Claims

1. An artificial disc replacement (ADR), comprising:

a flattened piston and cylinder adapted for placement between an opposing pair of vertebral bodies;

the piston having an exposed, articulating top surface, a bottom surface, and an outer sidewall;

the cylinder having a bottom portion and an inner sidewall dimensioned to receive the outer sidewall of the piston in sliding engagement;

a cavity within the cylinder between the bottom of the piston and the bottom of the cylinder, the cavity being filled with a hydrogel of the type that imbibes fluid; and

one or more bidirectional channels into the cavity, allowing the hydrogel to expel fluid when the piston is compressed into the cylinder and take up fluid when the compression is released.

2. The ADR of claim 1, further including a mechanism to limit the relative movement of the endplates.

3. The ADR of claim 1, wherein the articulating top surface of the piston is convex.

4. The ADR of claim 1, wherein the fluid paths are formed through the piston.

5. The ADR of claim 1, wherein the bottom of the cylinder is formed with a second sliding piston, the second piston having an exposed, articulating bottom surface and a top surface in contact with the hydrogel.

6. The ADR of claim 5, wherein the articulating bottom surface of the second piston is convex.

7. The ADR of claim 5, further including an endplate component between the articulating bottom surface of the second piston and a lower vertebral body.

8. The ADR of claim 1, further including an endplate component between the articulating top surface of the piston and an upper vertebral body.