A bone fixation assembly may include a male member removably couplable with a female member. The male member may include a male load-sharing feature having at least one male load-sharing surface. The female member may include a female load-sharing feature having at least one female load-sharing surface. The female load-sharing feature may be positioned and shaped to receive the male load-sharing feature therein. In response to a bending load acting on the bone fixation assembly, at least one of the male member and the female member may bend such that, at least a portion of the at least one male load-sharing surface engages with at least a portion of the at least one female load-sharing surface to distribute the bending load between the male member and the female member.

A bone cut guide includes a first portion having a first cut slot and having an aperture for receiving a wire to connect the first portion to a first bone. A second portion has a second cut slot and a second aperture for receiving a second wire to connect the second portion to a second bone. The first portion and the second portion are movably connected to each other to allow the first bone and the second bone to move relative to each other.

A spine alignment system is disclosed. The spine alignment system includes a pedicle screw having a longitudinal axis, the pedicle screw having a screw head. The screw head includes a slot having a longitudinal axis that is substantially perpendicular to the longitudinal axis of the pedicle screw. An extension shaft is secured to the pedicle screw, such that a longitudinal axis of the extension shaft is substantially coaxial with the longitudinal axis of the pedicle screw. The spine alignment system also includes a cap having a slot that forms a substantially cylindrical passage with the slot of the pedicle screw head. The substantially cylindrical passage is configured to receive an alignment rod such that alignment of the spine occurs as the rod is translated along the extension shaft to the pedicle screw.

A femur fixation system includes an intramedullary nail that includes a first bending stiffness and a bone plate that includes a second bending stiffness and a second torsional stiffness. In the femur fixation system either at least one of the second torsional stiffness compensates for the first torsional stiffness and the first torsional stiffness is insufficient to enable the intramedullary nail to stabilize the bone fracture independently of the bone plate or the first bending stiffness compensates for the second bending stiffness and the second bending stiffness is insufficient to enable the bone plate to stabilize the bone fracture independently of the intramedullary nail.

Apparatus and methods are provided for using a plate to fuse bones together, including reducing or stabilizing a fracture or osteotomy. Legs of the plate are inserted into pre-drilled guide holes in one of the bones and one or more screws are inserted through apertures and into another of the bones to secure the plate to the bones. A plate insertion tool can be used to temporarily tension the legs prior to insertion into predrilled guide holes in a bone by bending or pivoting the legs away from the body. A tensioning tool can be used to tension the plate after the legs are inserted into the guide holes in the bone and during the insertion of one or more of the screws.

A bone plate and method for use thereof affords use of at least two surgical approaches to attach the bone plate to a fractured bone to facilitate reduction and repair thereof. The bone plate includes two domains extending in different directions from a transition zone. The directions in which each of the two domains extend are generally opposite, and the transition zone is configured to afford portions of the two domains to be substantially disposed in planes that are transverse to one another.

An orthopedic instrument, comprising a pair of pivotally-connected arms, extending beyond a pivot axis of a first pivot; a pair of feet mounted to ends of the pair of pivotally-connected arms; and a quadrilateral linkage configured to maintain parallelism between the pair of feet over a range of angles and to selectively alter a distance between the pair of feet.

An external adjustment device includes at least one permanent magnet configured for rotation about an axis with a first handle extending linearly at a first end of the device and a second handle at a second end of the device, the second handle extending in a direction substantially off axis to the first handle. The external adjustment device further includes a motor mounted inside the first handle and a first button located in the proximity to one of the first handle or the second handle, the first button configured to be operated by the thumb of a hand that grips the one of the find handle or second handle. The first button is configured to actuate the motor causing the at least one permanent magnet to rotate about the axis in a first direction.

A pivotal spinal fixation system includes bone anchors comprising capture portions having a partial spherical shape with flat side surfaces, multi-planar receivers with continuous interior circumferential engagement surfaces proximate their bottom openings, and uni-planar receivers with non-continuous interior circumferential engagement surface proximate their bottom openings. The system also includes circular retainers, each having a non-continuous outer circumferential surface configured for non-pivotal engagement with the interior circumferential engagement surfaces of both the multi-planar receivers and the uni-planar receivers, and an inner surface configured to expand and contract around the capture portion and flat side surfaces of a bone anchor so as to capture the bone anchor within a multi-planar or uni-planar receiver. The system provides for pivotal motion of the bone anchors in any of a plurality of angular directions relative to the vertical centerline axes of the multi-planar receivers while limiting pivotal motion to a single pivot plane relative to the vertical centerline axes of the uni-planar receivers.

An electronically assisted artificial vertebral disc having an upper disc plate and a lower disc plate is disclosed. An actuator imparts movement to at least one of the upper and lower disc plates. A control device controls the actuator and the amount of movement between the disc plates. The actuator includes a plurality of either linear actuators or rotary actuators that are driven by electric motors in response to the control device. The control device includes at least a first sensor for detecting the position of the actuator and at least a second sensor for detecting the spatial orientation of at least one of the upper and lower disc plates. The control device also preferably includes a microprocessor that calculates the desired positions of the upper and lower disc plates and provides a control signal to the actuator to drive the upper and lower disc plates to their desired positions.