An intervertebral implant may include a shaft having a proximal end, a distal end, a longitudinal axis, a minor diameter, and a helical thread disposed about the shaft along the longitudinal axis between the proximal end and the distal end of the shaft. The helical thread may include a major diameter and a concave undercut surface angled towards one of the proximal end and the distal end of the shaft. The intervertebral implant may be implanted within an intervertebral space between a superior vertebral body and an inferior vertebral body. A ratio of the major diameter to the minor diameter may be less than 1.50. The concave undercut surface may engage the superior vertebral body and the inferior vertebral body and may be shaped to resist at least one force transmitted between the superior vertebral body and the inferior vertebral body to stabilize the intervertebral space.

A bone disunion fastener may include a fastener shaft, a helical thread, and a bone staple. The helical thread may include a concave undercut surface oriented towards one end of the fastener shaft. The bone staple may include a first bone-engaging feature, a second bone-engaging feature, and a middle portion with an opening. The bone disunion fastener may be implanted along a disunion between a first bone portion and a second bone portion. The concave undercut surface may be shaped to resist at least one force transmitted between the first bone portion and the second bone portion to stabilize the disunion. The first bone-engaging feature may engage the first bone portion and the second bone-engaging feature may engage the second bone portion to couple the bone staple to the bone portions and resist at least one force transmitted between the bone portions to stabilize the disunion.

A bone fixation system comprises a first fastener configured to anchor into a first vertebrae, a second fastener configured to anchor into a second vertebrae, and a set screw to retain the second fastener to the first fastener. The first fastener includes a shaft extending along a longitudinal axis and a head. The shaft includes a first cylindrical body. The head of the first fastener includes a second cylindrical body defining a passageway having an interior surface. The passageway defines a longitudinal axis that is different than the longitudinal axis of the shaft. The first cylindrical body of the shaft and the second cylindrical body of the head are angled relative to each other. A head of the second fastener is configured to engage the interior surface of the passageway of the head of the first fastener. The set screw retains the head of the second fastener in the passageway.

Disclosed is a fenestrated bone anchor suitable for being anchored in live bone tissue of a human or animal patient. The bone anchor comprises a shaft with a proximal end and a distal end and a circumferential surface extending from the proximal end to the distal end. The shaft further comprises a longitudinal cavity extending from the proximal end towards the distal end and a plurality of lateral channels extending through a wall of the shaft from the axial cavity to the circumferential surface. The lateral channel has a pear-shaped cross section and/or the thickness of the wall increases gradually in selected ones of directions towards the lateral channels. The fenestrated bone anchor is e.g. a component of a surgical system comprising an interbody fusion device of the stand-alone type.

A method for implanting an intrafacet implant includes making an incision, advancing an instrument assembly through the incision and to a facet joint. The instrument assembly includes a guide having a lumen extending therethrough. The method includes anchoring the guide at the facet joint, advancing an intrafacet implant to the facet joint through the guide using an inserter, and countersinking the intrafacet implant within the facet joint using the inserter.

A pivotal bone anchor assembly includes a shank having an anchor portion and a head with a partially spherical outer surface, a drive socket, an annular planar top surface surrounding the drive socket, and a frusto-conical surface between the planar top surface and the partially spherical outer surface. The assembly further includes a receiver having a base defining an axial bore and an upper portion defining a channel configured to receive a rod, and an insert positionable within the axial bore having an upper surface engageable with the rod, a lower surface for transferring a downwardly-directed force toward the head, and a central aperture for accessing the drive socket, with the rod extending across the central aperture when the fixation rod is engaged by the upper surface. After the head, the insert, and the rod are positioned in the receiver, the frusto-conical surface remains spaced apart from the rod to provide for increased articulation of the shank relative to the receiver.

A device for treating orthopaedic trauma includes a device body having an exterior surface and a cannulation formed therein that extends from one longitudinal end of the device body to an opposite longitudinal end of the device body and at least one porous ingrowth material region associated with the exterior surface of the device body and fluidly coupled to the cannulation. The at least one porous ingrowth material region is configured to deliver a therapeutic agent from the cannulation to a region outside the device body.

A bone screw comprising a shaft having a wall, the wall including a minor diameter and at least one thread having an external thread form. The thread form including a first portion comprising a crest of the thread form and a second portion extends between a minor diameter of the thread form and the first portion. The first portion having a solid configuration relative to the second portion. In some embodiments, systems, spinal constructs, surgical instruments and methods are disclosed.

A fixation device is disclosed including an elongate body extending from a distal end to a proximal end. The distal end defines a blind hole having a diameter and extending to a depth from a distal tip. The diameter of the blind hole is sufficient to receive a k-wire therein.

A bone screw, for drawing first and second bone fragments together, includes a shaft having a distal section and a proximal section. The distal section has a first external male screw thread and a minor diameter. The proximal section has a second external male screw thread. A major diameter of the distal section is larger than a major diameter of the proximal section. The bone screw includes a sleeve that has an internal female screw thread configured to mate with the second male screw thread. A distal portion of the sleeve has an outer diameter. The outer diameter is equal to or smaller than the minor diameter of the distal section of the shaft.