Expandable cotton and evans implants

An expandable implant comprising:

• a bottom endplate having a front end, an opposite rear end, and a pair of sidewalls connecting the front and rear ends and defining opposite sidewall grooves;
• a top endplate pivotably connected to the front end of the bottom endplate, the top endplate having an outer surface with a plurality of teeth configured to engage bone and an inner surface defining a pair of ramps;
• an actuator including a center slot and non-threaded bore, a pair of pivot slots on opposite sides of the center slot, and a pair of outwardly extending tabs receivable in the grooves in the bottom endplate to guide translation of the actuator;
• a pair of actuator pivots, each pivot having a ring receivable within the respective pivot slot of the actuator and secured via a pin and a foot configured to mate with one of the ramps on the top endplate;
• and
• a drive screw positioned through the non-threaded bore in the actuator and threadedly engaged with the bottom endplate, and wherein rotation of the drive screw pulls the actuator forward, thereby causing the two actuator pivots to slide along the ramps of the top endplate to expand the top endplate away from the bottom endplate.

A method of correcting a bone deformity comprising:

• forming an osteotomy in bone;
• inserting an expandable implant into the osteotomy, the expandable implant having a bottom endplate, a top endplate pivotably connected to the bottom endplate, an actuator with curved ramps configured to engage with angled ramps on the top endplate, and a drive screw configured to move the actuator;
• and
• expanding the implant to correct the bone deformity by rotating the drive screw to translate the actuator, thereby expanding the top endplate away from the bottom endplate, wherein the curved ramps on the actuator mate with the angled ramps on the top endplate to achieve tangential surface contact at any degree of implant expansion.