Various temporary fixation devices, fixation systems and kits, and methods of fixing a bone plate to a bone are described. A temporary fixation device includes a wire member and a retaining member. The wire member has a proximal end, a distal end, a flange disposed between the proximal end and the distal end, a first portion extending from the proximal end to the flange and defining a first outer diameter, and a second portion extending from the distal end toward the flange and defining a second outer diameter and a second portion outer surface. The retaining member defines an inner passageway and can be disposed on the second portion of the wire member such that the retaining member is movable along the second portion of the wire member, from the distal end to the flange. The elongate member comprises a first material and the stopping member comprises a second material that is different from the first material.

A surgical screw is provided for use in fixing or fusing bone. The screw may include each of an inner and an outer helical thread that extends along its length. The geometries of the helices and the relationship between the inner thread and the outer thread may improve the performance of the screw. For example, the two helices may operate to improve the manner in which the screw can be strained.

The bone screw with internal extendable is a bone screw with an internal, extendable tang. The tang—part of a tang system—is concealed within the body of the screw until after placement. After the screw is threaded into the bone, the internal tang system is pushed out of the bone screw body, forcing one or more tangs to extend out of the body and into the bone. A driver allows the user to control the different steps of insertion, including converting rotational motion of a knob into linear motion of a rod, the rod moving through the screw body to force the tang to exit the bone screw body. The one or more tangs preferably exit the bone screw body at a tang exit portal formed by one or more tang exit guide surfaces.

A bone rivet is provided that may be used as an alternative to a bone screw for bone fixation. The bone rivet includes a head and a threaded shaft that can be expanded upon installing the bone rivet into bone. A channel extends through the bone rivet and is shaped corresponding to a bulb of a mandrel used for installing the bone rivet. A first section of the channel has a smaller width than the mandrel's bulb to enable the bulb to expand the threaded shaft and a second section is sized to have a greater width. The installation process eliminates the task of rotating a typical bone screw during its installation. The threaded shaft also includes a cutting flute, which cuts a thread path for the threaded shaft into the bone thereby reducing the amount of torque needed to rotate and remove the bone rivet from bone.

A medical implant assembly including a receiver and a fastener. The receiver having helically wound thread extending up to a top surface thereof. The fastener having an axis of rotation and a continuously helically wound thread form. The continuously helically wound thread form having a start structure and an upper loading surface extending between a root and a crest of the continuously helically wound thread form. The start structure having a leading face extending below the upper loading surface. The leading face including a partial curvate surface extending between the root and the crest. The start structure being configured as a single lead start structure and a dual lead start structure.

Threaded sacro-iliac joint stabilization (e.g., fusion, fixation) implants and methods of implantation and manufacture. Some implants include a threaded distal region, an optionally threaded central region, and an optionally threaded proximal region. The distal, central, and proximal regions have lengths such that when the implant is laterally implanted across a SI joint, the distal region can be positioned in a sacrum, the central region can be positioned across an SI-joint, and the proximal region can be positioned in an ilium.

A fastener with improved threading for resisting multi-axial forces and off-axis loading scenarios is provided. The fastener may include a shaft and a plurality of helical threads disposed about the shaft. The plurality of helical threads may include a first helical thread and a second helical thread adjacent the first helical thread. The first helical thread may include a first concave undercut surface and a first convex undercut surface. The second helical thread may include a second concave undercut surface and a second convex undercut surface. When the fastener is viewed in section along a plane intersecting a longitudinal axis of the shaft, the first concave undercut surface and the second convex undercut surface may be oriented toward the proximal end of the shaft, and the first convex undercut surface and the second concave undercut surface may be oriented toward the distal end of the shaft.

The invention comprises a method for fixating bones in the foot by aligning the bones in their desired position, inserting a screw in the aligned bones, inserting at least one transverse element near the head or tip of the screw, and tightening the screw to compress the bones. The screw comprises a shaft having first and second ends with spirally wound screw threads beginning near the first end and extending along the shaft. Advantageously, the screw is cannulated and screw threads are formed on an interior surface of the cannulation. Illustratively, the transverse elements may be staples, open-ended washers, or open-ended nuts. Reduction instruments and drill guides used in the invention are also disclosed.

A bone anchor includes a shank having a free end, a longitudinal axis, a channel extending axially through the shank to the free end, the channel having a first width, and at least one opening extending through a wall of the shank, and a narrowing member including an elastically deformable portion configured to extend into the channel at or near the free end. The narrowing member is adjustable from a first configuration where the deformable portion defines an opening with a width smaller than the first width to restrict a substance from exiting through the free end, to a second configuration where the deformable portion is deformed radially outwardly to define an opening with a width that is at least the first width, while at least a portion of the shank positioned at a same axial height as the deformable portion maintains a constant outer width.