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