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 instrument system may include a first bone pin, a second bone pin, and a guide block. The guide block may include first and second bone pin holes to receive the first and second bone pins, and a window intermediate the first and second bone pin holes. The first bone pin may be anchored in a first bone portion and inserted through the first bone pin hole, and the second bone pin may be anchored in a second bone portion and inserted through the second bone pin hole to impart a compression or distraction force on a bone disunion between the first and second bone portions. The window formed through the guide block may provide access for an implant placed through the window to stabilize the bone disunion while the bone disunion is placed under a compression or distraction force.

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 fastener system can comprise a fastener and a first sizing component. The fastener can comprise a shaft that provides an anchoring footprint. The first sizing component can be configured to be connected to the shaft and can include a first anchoring feature, or circumferential bone engaging feature, to increase a size of the anchoring footprint. The first anchoring feature can comprise a sleeve that radially expands a diameter of the threaded shaft. The first anchoring feature can comprise axially extending teeth. The system can further comprise a second sizing component including a second anchoring feature to increase the size of the anchoring footprint, the second anchoring feature being different from the first anchoring feature. The second anchoring feature can expand the diameter of the threaded shaft a greater amount than the first anchoring feature. The second anchoring feature can have a length greater than the first anchoring feature.

A compression device made of a superelastic material having a peripheral portion with an upper surface, a lower surface, and a central opening extending therethrough is provided. One or more resilient teeth project inward of the peripheral portion into the central opening and are configured to exert a biasing force in an axial direction when deformed in a direction opposite the axial direction.

An orthopedic system configured for use in a pre-operative, intra-operative, and post-operative assessment. The orthopedic system comprises a first screw, a second screw, a first device, a second device, and a computer. The first device and the second device are respectively coupled to a first bone and a second bone of a musculoskeletal system. The first and second devices each include electronic circuitry, one or more sensors, and an IMU. A bracket, wrap, or sleeve can be used to hold the first and second devices to the musculoskeletal system. The first and second devices are configured to send measurement data to a computer. The first and second devices each have an antenna system. Electronic circuitry in the first or second devices are configured to harvest energy from a received radio frequency signal to recharge a battery to maintain operation.

The invention relates to a bone anchor for triangular iliosacral osteosynthesis. The bone anchor includes an ilium screw having a first longitudinal direction and an iliosacral screw having a second longitudinal direction. The ilium screw, in a thread-free portion, has a preferably elongated-hole-like through-opening transversely to the first longitudinal direction, and the iliosacral screw has such a smaller outer diameter in relation to the ilium screw that the iliosacral screw can be guided through the through-opening and can be screwed proceeding from the ilium into the sacrum, through the ilium screw.

A compression device made of a superelastic material having a peripheral portion with an upper surface, a lower surface, and a central opening extending therethrough is provided. Tips of one or more resilient structures of the compression device project inward of the peripheral portion and form an opening. The one or more resilient structures are configured to exert a biasing force in a direction when deformed in an opposite direction. Also provided is a bone plate assembly comprising a captively retained compression device and a bone plate comprising one or more integrally formed resilient structures.

A compression device made of a superelastic material having a peripheral portion with an upper surface, a lower surface, and a central opening extending therethrough is provided. One or more resilient teeth project inward of the peripheral portion into the central opening and are configured to exert a biasing force in an axial direction when deformed in a direction opposite the axial direction.

A retention system includes a first member having an inner surface defining a first thread form. The first thread form includes a first stage having a first pitch and a second stage having a second pitch that is greater than the first pitch. A second member includes a shaft and a neck. The shaft includes an outer surface defining a second thread form configured to engage the first thread form to lock the second member with the first member. The neck includes a smooth unthreaded section. Methods of use are disclosed.