A positioning block (10) for use in total knee replacement surgery, permitting five degrees-of-freedom movement relative to a bone element (39) to which it is fixed. The positioning block (10) comprises a rotational mounting element (14) that is removably engaged to the bone element such that the mounting element (14) is selectively rotatable relative to the bone element, about three substantially perpendicular axes of rotation. A guide body portion (12) is engaged with the mounting element (14) such that it is translatable relative thereto along a proximal-distal axis (43) and an anterior-posterior axis (47), while being rotationally fixed relative to the mounting element (14) such that the guide body portion (12) and the mounting element (14) rotate together relative to the bone element (39).
