The present invention relates to a surgical navigation device, for the purpose of adjusting cutting planes to a desired position with respect to a bone of a patient, the device comprising:an adjustable guide (15) that contains several adjustable screws (1) that create contact points with the surface of the bone or cartilage such that the guide fits to the bone in a unique position calculated such that the holes and cutting blocks of the adjustable guide fit with the position planned on preoperative CT or MR images of the patient,a dedicated screwdriver (7) to adjust automatically the screws (1) to their target length,a navigation system used to check the correct position of the adjustable guide with respect to essential anatomical points and if necessary means to correct the positions of the adjustable screws.
