Bone fixation device

• US 5,893,850 A
• Filed: 11/12/1996
• Issued: 04/13/1999
• Est. Priority Date: 11/12/1996
• Status: Expired due to Term

• Current Assignee: Depuy Synthes Products Incorporated (Johnson & Johnson)
• Original Assignee: Victor V. Cachia
• Inventors: Cachia, Victor V.
• Primary Examiner(s): Buiz, Michael
• Assistant Examiner(s): SHAI, DAPHNA
• Application Number:
  US08/745,652
• Time in Patent Office: 882 Days
• Field of Search: 606/60, 606/61, 606/63, 606/64, 606/65, 606/72, 606/73
• US Class Current: 606/326
• 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: A61B 17/683 comprising bone transfixation elements, e.g. bolt with a distal cooperating element such as a nut

Abstract

Disclosed is a bone fixation device of the type useful for connecting two or more bone segments during the healing process. The device comprises an elongate pin having a distal anchor thereon. A proximal anchor is axially movably disposed with respect to the pin, to accommodate different bone dimensions and permit appropriate tensioning of the fixation device. The bone fixation device may comprise bioabsorbable or permanent materials such as poly-p-dioxanone, poly L-lactide (PLLA), nylon or stainless steel.

Claims

1. A bone fixation device, comprising:

an elongate pin body having proximal and distal ends;

a distal anchor on the pin body, said distal anchor moveable between a reduced cross-sectional area for implantation of the device and an enlarged cross-sectional area for anchoring the device, said distal anchor biased in the direction of the enlarged cross-sectional area;

a proximal anchor, axially movably carried by the pin body, said proximal anchor comprising a tubular housing coaxially disposed about the pin body;

said tubular housing comprising at least one radially inwardly facing surface structure which cooperates with a ramped surface on the pin body to permit distal travel of the proximal anchor with respect to the pin body but which resists proximal travel of the proximal anchor with respect to the pin body;

an anchor retention structure on the pin body for permitting distal motion of the proximal anchor with respect to the pin body but resisting proximal motion of the proximal anchor relative to the pin body, said retention structure comprising at least one ramped surface that inclines radially outwardly in the distal direction.

2. A bone fixation device as in claim 1, wherein said fixation device comprises poly-p-dioxanone, PGA, PLLA or other bio-absorbable or biologically incorporated substance.

3. A bone fixation device as in claim 1, said housing having a radially-outwardly directed annular flange on the proximal end thereof.

4. A bone fixation device as in claim 1, wherein the distal anchor is radially enlargeable from a first, reduced diameter for passing through an aperture in a bone in a distal direction, and a second, relatively larger diameter for resisting movement of the distal anchor in a proximal direction through the aperture in the bone.

5. A bone fixation device as in claim 4, wherein the distal anchor is biased towards the larger diameter.

6. A method of fixing two or more adjacent bone components with respect to each other, comprising the steps of:

drilling a hole through a first and a second adjacent bone components;

providing a bone fixation device of the type having an elongate pin body, a distal anchor on the pin body, and a proximal anchor axially movably supported by the pin body, said distal anchor moveable from an insertion orientation to an anchoring orientation and biased in the direction of the anchoring orientation;

advancing the bone fixation device through the hole with the distal anchor restrained in the insertion orientation until the distal anchor projects through the distal end of the hole;

permitting the bias to automatically move the distal anchor from the insertion orientation to the locking orientation;

applying a proximal traction on the pin body;

advancing the proximal anchor distally along the pin body to apply a compressive force to the bone components; and

retaining the compressive force by an anchor retention structure that permits distal travel of the proximal anchor but resists proximal movement of the proximal anchor with respect to the pin body.