Expandable tibial tray insert trial

An expandable tibial tray trial comprising:

• top and bottom plates configured to nest together in a collapsed position;
• an actuation screw configured to rotate about an actuation axis, the actuation screw having a head and a shaft defining a helical cut, the head defining a plurality of indicators about its circumference;
• and
• an expansion ramp having a ramped body with a pair of vertical support walls defining a channel therebetween for receiving the actuation screw and a cross-pin extending across the channel and configured to pass through the helical cut of the actuation screw,
• wherein when the actuation screw is rotated, the ramped body translates along the actuation axis and expands the top plate, thereby moving the top plate to an expanded position such that one of the indicators corresponds to a discrete height of the expanded trial.

A method for trialing an implant, the method comprising:

• attaching a modular articular insert trial to an expandable trial;
• positioning the expandable trial in a surgical site, the expandable trial having top and bottom plates, an actuation screw having a helical cut with step portions separated by a thread rise, and an expansion ramp having a pin configured to ride along the helical cut;
• and
• rotating the actuation screw to cause the expansion ramp to slide along the bottom plate and lift the top plate as the ramp translates forward, wherein when the pin rests in one step portion of the helical cut, the expandable trial is expanded to a discrete thickness.