Johnson & Johnson Professional, Inc.

Laurel Rogers

Jorge A Ochoa

Stephen Ferrer Wilson

Allan Ritchie

A bone fixation device such as a screw, pin, staple, cable or anchor has a microtextured contact surface to enhance installation or gripping characteristics, preferably by providing directional or anisotropic engagement. A surface texture comprised of patterned microfeatures imparts a roughness or actual mechanical engagement that prevents loosening. In different embodiments the features resemble an array of microbumps or pyramids, or anisotropic features such as rasp teeth, shingles, or slanted cantilevered fiber/rods. The use of microbumps present a smaller surface area when moving, while providing full area contact after the surfaces have relaxed or decompressed; installation may be effected with low force, while high static or resting friction prevents disengagement. Features with directional asymmetry or angled suspension allow the textured surface to slide or deflect when the fixation device moves in one direction, while presenting a high resistance to torque or linear motion when moved in the other direction. Manufacturing is achieved with ion beams or directional treatment with energetic radiation, and regular arrays of the microfeatures may be produced as stationary surface growth phenomena without the use of pattern masks or mechanical contact. One manufacturing apparatus rotates the fixation device about a longitudinal axis while it is irradiated along an oblique axis. A bone pin may have centrally-directed spurs that allow a multi-segment fracture to be securely pinned without threading. An elastic fastener body such as a screw or pin can be pre-tensioned to place the bone under a torsional or compressive load, or introduce strain at the healing site.

Directional bone fixation device

A bone plug for intramedullary insertion into the canal of a bone to restrict the bypass of cement during implant surgery is described. The bone plug is made of a bioabsorbable material and has a tapered central body providing the primary support for the plug. A plurality of radially extending disc-like fins extend from the body at spaced locations. The taper provides the distal fin with a greater degree of flexibility due to the long cantilever, thus permitting an ease of insertion into the intramedullary canal while the larger diameter body and shorter proximal fins lend structural stiffness to resist the migration of the device.

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North Attleboro, MA, United States of America

Laurel Rogers