An implantable segmented intramedullary structure adapted to be received in the intramedullary canal of a bone configurable between a relatively flexible, bent configuration for implantation or extraction and a relatively rigid, straightened configuration for bone treatment. The segmented intramedullary structure comprises a plurality of interconnected segments with a first interface and a complementarily-shaped second interface such that the first interface of a segment cooperatively engages the second interface of an adjacent segment. The segments define a channel for a tensioning member to lock the structure in a compressed configuration.