Bioabsorbable rivet bone fastener

Abstract

Bone fasteners consisting of a rivet and an expansion pin for attaching soft tissue and bone plates to bone. The rivet has an enlarged proximal end, a tubular body portion dimensioned to fit snugly within a hole drilled in a bone, and a distal end having expandable legs. The expansion pin is either slidably or rotatably mounted within an axial bore in the rivet. In a first embodiment, the expansion pin has a metallic traction portion and a conical, preferably bioabsorbable, distal end portion releasably affixed thereto. In use, the rivet is inserted into a pre-drilled hole in a bone. When tension is applied to the traction portion of the expansion pin, the conical end portion progressively advances into the bore thereby forcing the legs on the distal end of the rivet to expand outwardly. When the legs are fully expanded, further progress of the conical portion is arrested by a shoulder stop within the axial bore. Further tension on the traction portion breaks the expansion pin, leaving the conical distal end within the expanded bore. In a second embodiment, a conical expansion pin is pressed into the rivet's axial bore from the proximal end of the bore. In a particularly preferred embodiment, rotation of an expansion pin housed within the rivet's axial bore exerts an outwardly directed force on the legs. When the legs are sufficiently expanded, a groove detent within the bore resists further rotation of the expansion pin. All embodiments of the rivet bone fasteners can be adapted for compression reduction of a fracture. With all embodiments of the bone fasteners, both the rivet and the expansion pin, or portions thereof, may be fabricated from either bioabsorbable or nonabsorbable materials, the choice of material depending on the application.

Dependencies are inferred from the claim text.