The invention relates to a surgical navigation device, for the purpose of adjusting a cutting plane to a desired position with respect to a bone of a patient, the device comprising: a fixed part (7) rigidly attached to the bone (18, 19), the fixed part comprising fixation means to rigidly attach a tracker thereto a mobile part (5) adjustable with respect to the fixed part (7), including fixation means to rigidly attach a tracker thereto, and including a cutting slot (6) in which a saw blade can be inserted to perform cut a fixed tracker (9) rigidly attached to the fixed part (7) a mobile tracker (1) attached to the mobile part (5). The invention also concerns a method for adjusting a cutting plane of a surgical device to a desired position with respect to a bone of a patient.
