Orthopaedic appliance and method of preparing

• US 5,476,880 A
• Filed: 07/28/1994
• Issued: 12/19/1995
• Est. Priority Date: 02/20/1992
• Status: Expired due to Fees

• Current Assignee: Orthopaedic Research Institute Incorporated of Wichita, Curators of the University of Missouri (University of Missouri)
• Original Assignee: Orthopaedic Research Institute Incorporated of Wichita, Curators of the University of Missouri (University of Missouri)
• Inventors: Yasuda, Hirotsuga K., Cooke, Francis W., Marrero, Thomas R.
• Primary Examiner(s): Michl, Paul R.
• Assistant Examiner(s): DeWitt, LaVonda R.
• Application Number:
  US08/281,831
• Time in Patent Office: 509 Days
• Field of Search: 523/115, 523/209, 523/212, 523/213, 523/222, 606/76, 606/92, 606/53, 606/70, 623/16, 623/23
• US Class Current: 523/115
• CPC Class Codes: A61B 17/8802 Equipment for handling bone cement or other fluid fillers
• CPC Class Codes: A61B 90/39 Markers, e.g. radio-opaque or breast lesions markers
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• CPC Class Codes: A61F 2002/3008 radio-opaque, e.g. radio-opaque markers
• CPC Class Codes: A61F 2002/4631 the prosthesis being specially adapted for being cemented
• CPC Class Codes: A61F 2250/0098 radio-opaque, e.g. radio-opaque markers
• CPC Class Codes: A61L 24/0094 containing macromolecular fillers
• CPC Class Codes: A61L 24/06 obtained by reactions only involving carbon-to-carbon unsaturated bonds A61L24/043, A61L24/046 take precedence
• CPC Class Codes: A61L 2430/02 for reconstruction of bones; weight-bearing implants
• CPC Class Codes: C08L 33/12 Homopolymers or copolymers of methyl methacrylate

Abstract

Improved polymeric orthopaedic compositions are disclosed wherein sized, functional fibers are incorporated into a physiologically acceptable matrix. The compositions of the invention can be fabricated in the form of particulate powders adapted for reinforcment of bone cements, continuous media for such cements, and orthopaedic implant coatings. A complete implant attachment system is also provided, made up of a fiber reinforced implant coating, and a compatible fiber-reinforced cement. In preferred forms, the fibers have a layer of sizing thereover which is chemically joined both to the surface of the fibers and to the surrounding matrix, and the fibers are present at a level of at least about 6 volume percent. If desired, sized radiopaque particles may be incorporated into the compositions of the invention. The fibers are advantageously polymeric in nature and of intermediate stiffness, whereas the matrix fraction is preferably polymethylmethacrylate.

Claims

1. A system for permanently installing an orthopaedic appliance, said system comprising:

a coating adapted for application on the surface of said appliance, said coating including a polymeric continuous phase having therein and extending outwardly from the surface thereof a plurality of fibers, said fibers having been treated for bonding of the surface of the fibers with said continuous phase; and

bone cement adapted for contacting and adhering to a bone surface, and for contacting said coating to establish a coating/bone cement interface, said bone cement including a polymeric continuous medium bonded with the portions of said fibers extending outwardly from the surface of said coating.

said fibers extending across said coating/bone cement interface.

2. A coated orthopaedic appliance comprising:

a rigid orthopaedic appliance presenting an outer surface; and

a coating applied over said outer surface and bonded with said surface,

said coating including a polymeric continuous phase presenting an outermost surface with a plurality of fibers within the continuous phase and extending outwardly beyond said coating outermost surface, said fibers being treated for bonding with said continous phase.

3. The appliance of claim 2, there being a sizing agent applied to said outer surface and bonded with both said outer surface and said coating.

4. A method of preparing an orthopaedic implant comprising the steps of:

providing a rigid orthopaedic implant presenting an outer surface; and

applying to said outer surface a coating comprising a physiologically acceptable polymeric continuous phase having a quantity of polymeric reinforcing fibers therein which extend outwardly from said coating, there being a layer of sizing material over said fibers and bonded with said fibers and continuous phase.

5. The method as set forth in claim 4, including the step of etching the outer surface of said coating material to remove from about 0.1-1 mm of the matrix material in order to expose the outer ends of said fibers.

6. The method as set forth in claim 5, said etching step comprising the steps of contacting said outer surface of said coating with an effective solvent for said continuous phase.