A positioning block for use in knee surgery includes a rotational mounting removably engageable to the bone element by a multi-axial fastener such that the mounting element is selectively rotatable relative to the bone element about at least two substantially perpendicular axes of rotation. A guide body portion is engaged with the rotational mounting element such that it is translatable relative thereto along while being rotationally fixed relative to the mounting element. The guide body portion is moveable relative to the bone element in at least three degrees of freedom, the three degrees of freedom including at least two rotational degrees of freedom and at least one translational degree of freedom. A trackable member on the guide body portion is identified and tracked by a computer assisted surgery system.