Artificial hip-joint

• US 5,725,597 A
• Filed: 11/08/1996
• Issued: 03/10/1998
• Est. Priority Date: 11/09/1995
• Status: Expired due to Fees

• Current Assignee: Sung Kwan Hwang
• Original Assignee: Sung Kwan Hwang
• Inventors: Hwang, Sung Kwan
• Primary Examiner(s): ISABELLA, DAVID J
• Application Number:
  US08/747,098
• Time in Patent Office: 487 Days
• Field of Search: 623/18, 623/19, 623/23, 606/65, 606/66, 606/67, 606/68
• US Class Current: 623/22.15
• CPC Class Codes: A61B 17/742 having one or more longitudinal elements oriented along or parallel to the axis of the neck
• CPC Class Codes: A61B 17/746 the longitudinal elements coupled to a plate opposite the femoral head
• CPC Class Codes: A61F 2/32 for the hip
• CPC Class Codes: A61F 2/34 Acetabular cups
• CPC Class Codes: A61F 2/3601 for replacing only the epiphyseal or metaphyseal parts of the femur, e.g. endoprosthetic femoral heads or necks directly fixed to the natural femur by internal fixation devices non-prosthetic internal fixation devices for the femoral head or neck A61B17/74
• CPC Class Codes: A61F 2/3609 Femoral heads or necks; Connections of endoprosthetic heads or necks to endoprosthetic femoral shafts A61F2/3601 takes precedence
• CPC Class Codes: A61F 2/3662 Femoral shafts
• CPC Class Codes: A61F 2/367 Proximal or metaphyseal parts of shafts trochanteric devices connected to said proximal parts A61F2/30739
• CPC Class Codes: A61F 2002/30079 magnetic
• CPC Class Codes: A61F 2002/30354 Cylindrically-shaped protrusion and recess, e.g. cylinder of circular basis
• CPC Class Codes: A61F 2002/30357 Stepped cylinders, i.e. having discrete diameter changes
• CPC Class Codes: A61F 2002/30364 Rotation about the common longitudinal axis
• CPC Class Codes: A61F 2002/30474 using an intermediate sleeve interposed between both prosthetic parts to be coupled
• CPC Class Codes: A61F 2002/30507 using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/30581 having a pocket filled with fluid, e.g. liquid
• CPC Class Codes: A61F 2002/30589 Sealing means
• CPC Class Codes: A61F 2002/30593 hollow
• CPC Class Codes: A61F 2002/30624 Hinged joint, e.g. with transverse axle restricting the movement
• CPC Class Codes: A61F 2002/30639 having rolling elements between both articulating surfaces
• CPC Class Codes: A61F 2002/30673 Lubricating means, e.g. synovial pocket
• CPC Class Codes: A61F 2002/30682 : Means for preventing migration of particles released by the joint, e.g. wear debris or cement particles
• CPC Class Codes: A61F 2002/3412 : with pins or protrusions, e.g. non-sharp pins or protrusions projecting from a shell surface
• CPC Class Codes: A61F 2002/3482 : Two hemispherical halves having completely different structures
• 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 2002/3625 : Necks
• CPC Class Codes: A61F 2002/3652 : Connections of necks to shafts
• CPC Class Codes: A61F 2210/009 : magnetic
• 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 2310/00011 : Metals or alloys

Abstract

An artificial hip-joint having a construction capable of reducing abrasion of a polyethylene layer formed within the acetabulum cup when the head of the femur pivots in the acetabulum cup. The artificial acetabulum cup is implanted in the acetabulum of a user'"'"'s pelvic bone and includes a hollow hemispherical member made of a metal. The polyethylene layer is formed on the inner surface of the hemispherical member. A femur head holder is fixed to the femur. The femur head holder includes a spherical metal femur head pivotally held in the artificial acetabulum cup, a shaft coupled at an upper end thereof to the femur head and adapted to support the femur head, a housing extending inclinedly through the greater trochanter of the femur and adapted to receive the shaft therein in such a manner that it rotates with respect to the shaft, and bearings mounted between the shaft and the housing and adapted to support axial and radial load applied to the shaft at the femur head by the weight of the user. The bearings allows the housing to rotate with respect to the shaft when the user performs a movement involving a rotation of the femur head in the acetabulum cup, so that the movement of the user can be conducted while preventing the rotation of the femur head in the acetabulum cup.

Claims

1. An artificial hip-joint comprising an artificial acetabulum cup implanted in the acetabulum of a user'"'"'s pelvic bone, the artificial acetabulum cup consisting of a hollow hemispherical member made of a metal and a polyethylene layer formed on the inner surface of the hemispherical member, and a femur head holder fixed to a femur, the femur head holder comprising a spherical metal femur head pivotally held in the artificial acetabulum cup, wherein the femur head holder further comprises:

a shaft coupled at an upper end thereof to the femur head and adapted to support the femur head;

a housing extending inclinedly through the greater trochanter of the femur and adapted to receive the shaft therein in such a manner that it rotates with respect to the shaft; and

bearing means mounted between the shaft and the housing and adapted to support axial and radial load applied to the shaft at the femur head by the weight of the user, the bearing means allowing the housing to rotate with respect to the shaft when the user performs a movement involving a rotation of the femur head in the acetabulum cup, so that the movement of the user can be conducted while preventing the rotation of the femur head in the acetabulum cup.

2. The artificial hip-joint in accordance with claim 1, wherein the bearing means comprises a taper roller bearing fitting around a middle portion of the shaft, and at least one needle bearing fitting around a lower portion of the shaft, whereby it can perform constructively stable rotating and load-supporting functions in a limited anatomical space given in the body of the user.

3. The artificial hip-joint in accordance with claim 2, wherein the housing has a larger-diameter portion provided at an upper portion thereof and adapted to receive the taper roller bearing, the larger-diameter portion having an opening at an upper end thereof, and a magnetic fluid member fixedly mounted to the upper end of the larger-diameter portion and adapted to seal the interior of the housing, the magnetic fluid member having an opening through which the shaft extends.

4. The artificial hip-joint in accordance with claim 3, wherein the sealed interior of the housing is filled with a lubricant for reducing a friction of the bearings.

5. The artificial hip-joint in accordance with claim 3, wherein the shaft is provided at an upper portion thereof with an annular protrusion adapted to prevent the taper roller bearing from separating from the shaft.

6. The artificial hip-joint in accordance with claim 1, wherein the housing has a lower end embedded in the femur and a stem provided at the lower end in such a manner that it is integral with the lower end, the stem being inserted into a space formed in a central portion of the femur after removing the marrow existing in the central portion of the femur.

7. The artificial hip-joint in accordance with claim 2, wherein the housing has a lower end embedded in the femur and a stem provided at the lower end in such a manner that it is integral with the lower end, the stem being inserted into a space formed in a central portion of the femur after removing the marrow existing in the central portion of the femur.

8. The artificial hip-joint in accordance with claim 3, wherein the housing has a lower end embedded in the femur and a stem provided at the lower end in such a manner that it is integral with the lower end, the stem being inserted into a space formed in a central portion of the femur after removing the marrow existing in the central portion of the femur.

9. The artificial hip-joint in accordance with claim 4, wherein the housing has a lower end embedded in the femur and a stem provided at the lower end in such a manner that it is integral with the lower end, the stem being inserted into a space formed in a central portion of the femur after removing the marrow existing in the central portion of the femur.

10. The artificial hip-joint in accordance with claim 5, wherein the housing has a lower end embedded in the femur and a stem provided at the lower end in such a manner that it is integral with the lower end, the stem being inserted into a space formed in a central portion of the femur after removing the marrow existing in the central portion of the femur.