Hybrid headless bone screw
AssigneeStabiliz Orthopaedics, Inc.
InventorDouglas Cerynik
Life of this patent
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Abstract
A hybrid headless compression screw includes a distal portion comprising a metallic material and a proximal portion comprising a polymeric material coupled to the distal portion. The metallic distal portion provides high insertion torques and prolonged fragment retention, while the polymeric proximal portion mitigates the risk of hardware prominence associated with all-metallic screws. The polymeric proximal portion may include a biodegradable polymer that degrades and resorbs within the body over time, preventing damage to articular joint surfaces. A drive mechanism transmits rotational force to the distal metallic portion while bypassing the proximal polymeric portion. The proximal and distal portions are coupled by overmolding, mechanical retention features, or other suitable means.
Claims20
A headless compression screw (10) comprising:
- a distal portion (20) comprising a metallic material, wherein the distal portion includes a drive feature (54) configured to engage a drive mechanism (45) that transmits rotational force to the headless compression screw (10;
- and
- a proximal portion (30) comprising a polymeric material, the proximal portion (30) being coupled to the distal portion (20).
A headless compression screw system comprising:
- a headless compression screw (10) comprising a distal portion (20) comprising a metallic material and a proximal portion (30) comprising a polymeric material coupled to the distal portion (20);
- and
- a cannulated tap (90) comprising cutting threads (92) at a proximal end thereof and stepped cutting flutes (57) of decreasing diameter along its length, the cannulated tap (90) being configured to prepare a bone hole for receipt of the headless compression screw (10).
A method of fixing a bone fracture, the method comprising:
- placing a guidewire (40) into a pre-drilled hole across a fracture site between an origin bone (100) and a bone fragment (110);
- advancing a cannulated tap (90) over the guidewire (40) until the cannulated tap (90) is flush with an articular joint surface (112);
- removing the cannulated tap (90) to leave a tapped hole (112a);
- inserting a headless compression screw (10) over the guidewire (40), the headless compression screw (10) comprising a distal portion (20) comprising a metallic material and a proximal portion (30) comprising a polymeric material;
- engaging a driver (45) through an open channel (32) of the proximal portion (30) with a drive feature (54) of the distal portion (20);
- and
- advancing the headless compression screw (10) until a proximal head surface (30a) of the proximal portion (30) is substantially flush with an articular joint surface (112a), thereby drawing the bone fragments (100, 110) together across the fracture site.
Dependencies are inferred from the claim text.