Femoral component for an implantable hip prosthesis

Patent metadata

Field	Value
Publication number	US-9271839-B2
Application number	US-201313829026-A
Country	US
Kind code	B2
Filing date	Mar 14, 2013
Priority date	Mar 14, 2013
Publication date	Mar 1, 2016
Grant date	Mar 1, 2016

Abstract

An orthopaedic prosthesis for use in a hip replacement surgery includes an implantable stem component. The implantable stem component includes a core and a shell extending over the core. The shell includes a polymeric material and is configured to receive a femoral head component. Metal foam may extend over a portion of the shell.

First claim

The invention claimed is:

1. An orthopaedic hip prosthesis, comprising:
a femoral head component including a spherical surface shaped to engage a prosthetic acetabular component, and
a femoral stem component, comprising:
a first shell including a neck configured to be secured to the femoral head component and an elongated body extending distally from the neck, the first shell being formed from a metal-polymer composite material,
a core positioned in the first shell, the core including a first core body extending into the neck of the first shell and a second core body extending into the elongated body of the first shell having a medial surface and a lateral surface positioned opposite the medial surface, the core being formed from a material having a high tensile strength and a high elastic modulus, and
a second shell extending over a proximal section of the elongated body of the first shell, the second shell being formed from a metallic foam and having a medial surface and a lateral surface positioned opposite the medial surface,

wherein when the orthopaedic hip prosthesis is viewed in a transverse plane, the first shell and the second shell define (i) a first thickness between a medial-most point of the medial surface of the second shell and a medial-most point of the medial surface of the first core body and (ii) a second thickness between a lateral-most point of the lateral surface of the second shell and a lateral-most point of the lateral surface of the first core body, and (iii) the first thickness is less than the second thickness,
wherein when the orthopaedic hip prosthesis is viewed in the transverse plane, the medial surface of the first core body is convex and the lateral surface of the first core body is convex, and
wherein when the orthopaedic hip prosthesis is viewed in the transverse plane, the medial surface of the first core body is defined by a first radius and the lateral surface of the first core body is defined by a second radius that is greater than the first radius.

2. The orthopaedic hip prosthesis of claim 1 , wherein:
the first shell includes a shoulder having a distal surface, and
the second shell includes a proximal end that is engaged with the distal surface of the shoulder.

3. The orthopaedic hip prosthesis of claim 1 , wherein:
the transverse plane is a first transverse plane extending through the first shell, the second shell, and the core,
the first shell has a medial surface and a lateral surface positioned opposite the medial surface, and
when the orthopaedic hip prosthesis is viewed in a second transverse plane extending through the orthopaedic hip prosthesis distal of the second shell, a third thickness is defined between a medial-most point of the medial surface of the first shell and a medial-most point of the medial surface of the first core body, the first thickness is greater than the third thickness.

4. The orthopaedic hip prosthesis of claim 1 , wherein the femoral head component includes a tapered bore, and the neck of the first shell includes a tapered post configured to be received in the tapered bore of the femoral head component.

5. The orthopaedic hip prosthesis of claim 4 , wherein the femoral head component includes a body including the spherical surface, and a polymeric insert positioned in the body, the insert having the tapered bore defined therein.

6. The orthopaedic hip prosthesis of claim 1 , wherein the metallic foam second shell is shaped to engage a surgically-prepared proximal end of a patient's femur.

7. The orthopaedic hip prosthesis of claim 1 , wherein the material of the core is selected from a group consisting of a cobalt-chromium alloy and a titanium alloy.

8. The orthopaedic hip prosthesis of claim 1 , wherein the second shell is formed from a titanium alloy.

9. The orthopaedic hip prosthesis of claim 1 , wherein the second shell is formed from a cobalt-chromium alloy.

10. The orthopaedic hip prosthesis of claim 1 , wherein:
the first shell includes a tapered post configured to be received in a tapered bore of an implantable head component and the elongated body extending distally from the tapered post,
the first core body of the core extends into the tapered post of the first shell and the second core body extends into the elongated body of the first shell, and
the second shell includes a porous outer surface shaped to engage a surgically-prepared proximal end of a patient's femur,
wherein the elongated body of the first shell includes a distal section shaped to engage the surgically-prepared proximal end of a patient's femur distal of the second shell.

11. An orthopaedic hip prosthesis, comprising:
a femoral head component including a spherical surface shaped to engage a prosthetic acetabular component, and
a femoral stem component, comprising:
a first shell including a neck configured to be secured to the femoral head component and an elongated body extending distally from the neck, the first shell including a polymeric material,
a core positioned in the first shell, the core including a first core body extending into the neck of the first shell and a second core body extending into the elongated body of the first shell, the second core body of the core having a medial surface and a lateral surface positioned opposite the medial surface, the core being formed from a material having a high tensile strength and a high elastic modulus, and
a second shell extending over a proximal section of the elongated body of the first shell, the second shell being formed from a metallic foam and having a medial surface and a lateral surface positioned opposite the medial surface,
wherein when the orthopaedic hip prosthesis is viewed in a transverse plane, the first shell and the second shell define (i) a first thickness between a medial-most point of the medial surface of the second shell and a medial-most point of the medial surface of the first core body and (ii) a second thickness between a lateral-most point of the lateral surface of the second shell and a lateral-most point of the lateral surface of the first core body, and (iii) the first thickness is less than the second thickness,
when the orthopaedic hip prosthesis is viewed in the transverse plane, the medial surface of the first core body is convex and the lateral surface of the first core body is convex, and
when the orthopaedic hip prosthesis is viewed in the transverse plane, the medial surface of the first core body is defined by a first radius and the lateral surface of the first core body is defined by a second radius that is greater than the first radius.

Assignees

• Depuy Synthes Products Inc

Inventors

• Armacost John M
• Keefer Ryan C
• Mcanelly Jeffrey A

Classifications

• A61F2002/30011

  differing in porosity · CPC title

• A61F2002/365

  Connections of heads to necks · CPC title

• A61F2002/30069

  elastomeric · CPC title

• A61F2310/00029

  Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium · CPC title

• A61F2310/00023

  Titanium or titanium-based alloys, e.g. Ti-Ni alloys · CPC title