Modular joint prosthesis

• US 5,194,066 A
• Filed: 02/27/1989
• Issued: 03/16/1993
• Est. Priority Date: 01/11/1988
• Status: Expired due to Term

• Current Assignee: DePuy Orthopaedics Incorporated (Johnson & Johnson)
• Original Assignee: Boehringer Mannheim Corporation
• Inventors: Van Zile, Richard R.
• Primary Examiner(s): ISABELLA, DAVID J
• Application Number:
  US07/316,039
• Time in Patent Office: 1,478 Days
• Field of Search: 623/16, 623/18, 623/19, 623/20, 623/21, 623/23
• US Class Current: 623/20.15
• CPC Class Codes: A61F 2/38 for elbows or knees
• CPC Class Codes: A61F 2/461 of knees
• CPC Class Codes: A61F 2002/30604 modular
• CPC Class Codes: A61F 2002/4619 for extraction

Abstract

A modular joint prosthesis for implantation in a body. A component adapted to be fixed to a long bone having an intramedullary canal includes an elongated male stem having a uniformly tapered outer surface. In order to accommodate the particular size of long bone to which the component is to be fixed, a properly sized female stem is attached to the male stem before the component is fixed to the long bone. The female stem is adapted to be received in the intramedullary canal for fixation thereto, and has a uniformly tapered inner surface, the angle of the taper being substantially similar to the angle of taper of the outer surface of the male stem. As a result, the male stem and female stem become locked together when the inner surface of the female stem engages the outer surface of the male stem. The proper size of female stem is obtained by selecting it from a family of female stems having a graduated sequence of different external dimensions. Tools are also disclosed for disengaging the male stem from the female stem as well as for disengaging the female stem from the bone.

Claims

1. A modular joint prosthesis for implantation in a body comprising:

a component adapted to be affixed within an intramedullary canal of a long bone, said component including a support plate, said support plate having a lower surface adapted to engage and bear against and be substantially coextensive with a complementary resected surface of the long bone and an elongated male stem integral with and extending transversely away from said support shelf, said male stem having a longitudinal axis and an outer surface which is uniformly tapered relative to the longitudinal axis and having a maximum outer diameter at a proximal end adjacent the lower surface and a minimum outer diameter at a distal end distant from the lower surface; and

a female stem having a longitudinal axis and extending between a closed distal end and an open proximal end, a portion of said female stem having a bore extending from the open proximal end a predetermined distance distally thereof, said bore defining an inner surface which is uniformly tapered relative to the longitudinal axis and having a maximum inner diameter at said proximal end and a minimum inner diameter distant therefrom, said inner surface of said female stem and said outer surface of said male stem generally forming an angular divergence within the range of +/-3 minutes of arc;

whereby said male stem and said female stem are configured to be locked together upon engagement of said inner surface of the female stem and said outer surface of the male stem enabling said male stem and said female stem to be received as a unit in the intramedullary canal of the long bone for fixation thereto to a depth at which said support shelf bears against the resected surface of the long bone.

2. A modular joint prosthesis as claimed in claim 1:

wherein said female stem has a maximum outer diameter at said proximal end and a minimum outer diameter at said distal end, said female stem being selected from a group of female stems having a graduated sequence of different lengths between said distal end and said proximal end, of different maximum outer diameters at said proximal end, and of different minimum outer diameters at said distal end, all to accommodate the particular size of long bone to which said component is to be fixed.

3. A modular joint prosthesis as set forth in claim 1:

wherein the long bone is a tibia; and

wherein said component is a tibial tray including a support plate adapted to be received at the resected surface at the proximal end of the tibia, said male stem being integral with said support plate and extending transversely therefrom.

4. A modular joint prosthesis as set forth in claim 1:

wherein said female stem has a threaded bore therein intermediate said inner surface and said distal end.

5. A modular joint prosthesis as set forth in claim 1:

wherein said female stem has an outer surface with at least one flat thereon to prevent rotation thereof in the intramedullary canal relative to the bone.

6. A modular joint prosthesis as set forth in claim 1:

wherein said component has a longitudinal bore therein extending through said male stem and being threaded for at least part of its length adjacent said proximal end; and

wherein said female component has a terminal surface adjacent said distal end.