A positioning device assembly for positioning a tool guide block for use in an orthopedic surgery includes a positioning device having a block body with a reference surface adapted to abut a bone element, and first and second adjustment mechanisms that are independently operable. The first adjustment mechanism permits rotation of the tool guide block about a medial-lateral extending axis to provide flexion-extension angle adjustment and the second adjustment mechanism permits rotation of the tool guide block about an anterior-posterior extending axis to provide varus-valgus angle adjustment. The second adjustment mechanism includes integral coarse and fine adjustment mechanisms. A tool guide block assembly mounted to the positioning device includes a platform portion which is engaged to the block body of the positioning device and the tool guide block which is releasably engaged with the platform.