A length adjustable modular screw includes a head portion that includes an expander assembly comprising a collet. The expander assembly has proximal and distal ends and includes first and second components that are slidably engagable by insertion of the first component in a through channel of the second component along a common axis. The length adjustable modular screw also includes a threaded portion suitable for insertion and retention within bone, the threaded portion including at a socket adapted to coaxially receive at least a portion of the distal end of the expander assembly. The length adjustable modular screw has a length that is selected by splaying at least a portion of the distal end of the engaged first and second elongate components of the expander assembly within the socket of the threaded component.
