An orthopaedic surgical instrument assembly includes an attachment device (12), an intramedullary orthopaedic surgical instrument (16), and a cutting block (14). The attachment device includes a housing (34), a rail (36,38) extending outwardly from the housing, and a mounting frame (32) positioned on the rail that is configured to slide relative to the housing along the rail. The intramedullary orthopaedic surgical instrument is removably coupled to the housing, and the cutting block is removably coupled to the mounting frame.
