a base element adapted to be fixed to a bone in the region of a condyle; and

at least one cutting jig adapted to be coupled to the base element, the cutting jig comprising:

a first slot for guiding a cutting tool, the first slot defining a first cutting plane with respect to the base element, the first slot configured to receive a cutting tool while the cutting jig remains coupled to the base element;

a U-shaped base part having a pair of U limbs, wherein, when the cutting jig is coupled to the base element, the pair of U limbs are parallel to the first cutting plane and at least a portion of the base element is received between the pair of U limbs;

a clamping lever pivotably supported at the U-shaped base part about an axis extending parallel to the first cutting plane and perpendicular to a longitudinal axis of the U limbs;

a clamping spindle extending parallel to the U limbs of the U-shaped base part and cooperating with the clamping lever via a thread; and

a turntable arrangement rotatably supported by one of the pair of U limbs, the turntable arrangement rotatable about an axis extending perpendicular to the first cutting plane, the turntable arrangement defining a second slot for guiding a cutting tool, the second slot configured to receive a cutting tool while the cutting jig remains coupled to the base element and while taking the respective knee anatomy into account, wherein the rotational position of the second slot relative to the first slot is fixed by rotational actuation of the clamping spindle and the clamping lever is simultaneously pivotable relative to the U-shaped base part to clampingly engage the base element.