Modular bone implant with pan and pins

• US 5,702,475 A
• Filed: 02/14/1996
• Issued: 12/30/1997
• Est. Priority Date: 10/04/1994
• Status: Expired due to Fees

• Current Assignee: Amir Zahedi
• Original Assignee: Amir Zahedi
• Inventors: Zahedi, Amir
• Primary Examiner(s): ISABELLA, DAVID J
• Application Number:
  US08/601,170
• Time in Patent Office: 685 Days
• Field of Search: 623/16, 623/18, 623/19, 623/20, 623/22, 623/23
• US Class Current: 623/22.21
• CPC Class Codes: A61B 17/68 Internal fixation devices , including fasteners and spinal fixators, even if a part thereof projects from the skin bone staples A61B17/0642
• CPC Class Codes: A61F 2/30721 Accessories
• CPC Class Codes: A61F 2/30749 Fixation appliances for connecting prostheses to the body
• CPC Class Codes: A61F 2/34 Acetabular cups
• CPC Class Codes: A61F 2002/30332 Conically- or frustoconically-shaped protrusion and recess
• CPC Class Codes: A61F 2002/30785 parallel
• CPC Class Codes: A61F 2002/3079 Stepped or enlarged apertures, e.g. having discrete diameter changes
• CPC Class Codes: A61F 2002/30841 Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/30892 parallel
• CPC Class Codes: A61F 2002/3401 with radial apertures, e.g. radial bores for receiving fixation screws
• 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 2220/0033 made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit

Abstract

In a bone implant with a pan that is designed so that it is mainly in the form of a segment of a sphere for receiving the head of a femoral bone prosthesis, and with pin-type fastening means for anchoring the pan in the hip bone of the patient. The pan further includes recesses to receive the fastening means. In order to create a modular pan replacement, the recesses are designed for an axially parallel arrangement of the fastening means, and the recesses can be provided with stops to prevent movement of the fastening means towards the interior of the pan. The fastening means are threadless in the area which is inserted into the hip bone of the patient.

Claims

1. A bone implant comprising a pan having an outer surface configured in a form of a segment of a sphere and an inner surface configured to receive a head of a femoral prosthesis, and pin-type fastening means to anchor the pan in the pelvic bone of the patient, the pan having recesses sized to receive the fastening means, and with the recesses being designed for an axially parallel arrangement of the fastening means, characterized in that the recesses have

axially parallel bores, each said bore converging conically toward an interior of the pan, and wherein said fastening means have a conically-shaped portion for insertion into said pan, and

stop means for preventing movement of the fastening means towards the interior of the pan, said fastening means being substantially free of threads in an area that is inserted into the pelvic bone of the patient.

2. Bone implant according to claim 1 characterized in that said fastening means includes a plurality of pins having different lengths.

3. Bone implant according to claim 1 characterized in that the number of recesses is greater than the number of fastening means.

4. Bone implant according to claim 1 characterized in that said recesses and said pins (2) each have a lengthwise axis that extend parallel to the insertion direction (4) of pan (1).

5. A bone implant for insertion within the pelvic bone of a patient, comprising

a pan portion having a substantially hemispherical shape forming an interior cavity, said pan portion having a plurality of recesses that extend between an outer surface and an inner surface of the pan portion, and

a plurality of fastener elements having a head portion and an outwardly extending shaft, said shaft being substantially free of threads along a portion of the shaft that is adapted to seat within the pelvis of the patient,

said recesses having a conically-shaped taper converging towards the inner surface of the pan portion for preventing at least one of said fastener elements when mounted within one of the recesses from being forced from said recess into said interior cavity.

6. The bone implant of claim 5 wherein said recesses extend parallel to a central axis of said pan such that said recesses are parallel to one another.