A computer-implemented medical data processing method for planning an implant placement into an anatomical structure of a patient , wherein the method precedes a later implant placement and therefore does not comprise or encompass any surgical activity, and wherein the method comprises executing, on a processor of a computer, the following steps: - a three dimensional image-dataset of the patient is received at the processor, showing at least the anatomical structure into which the implant is planned to be placed; - at least one requirement is received at the processor that has to be fulfilled by the implant when being placed in the anatomical structure so as to achieve a certain medical outcome; - a user input is received at the processor that involves determining a spatial position of a tracked medical device operated by a user, wherein a current spatial position of a virtual implant representation is adjusted in correspondence with the determined spatial position of the tracked medical device ; characterized by the following steps - a frame and an initial proposal for possible implant placements is calculated by the processor based on the three-dimensional image-dataset and the at least one requirement, wherein, within the frame, a spatial position of the implant with respect to the anatomical structure fulfills the at least one requirement of not entering a prohibited area of the anatomical structure , and wherein the initial proposal for a possible implant placement is shown in a display; - a current spatial position of the virtual implant representation is determined by the processor as a final implant placement via a user input received at the processor, wherein the final implant placement is within the frame for possible implant placements . - a three dimensional image-dataset of the patient is received at the processor, showing at least the anatomical structure into which the implant is planned to be placed; - at least one requirement is received at the processor that has to be fulfilled by the implant when being placed in the anatomical structure so as to achieve a certain medical outcome; - a user input is received at the processor that involves determining a spatial position of a tracked medical device operated by a user, wherein a current spatial position of a virtual implant representation is adjusted in correspondence with the determined spatial position of the tracked medical device ; characterized by the following steps - a frame and an initial proposal for possible implant placements is calculated by the processor based on the three-dimensional image-dataset and the at least one requirement, wherein, within the frame, a spatial position of the implant with respect to the anatomical structure fulfills the at least one requirement of not entering a prohibited area of the anatomical structure , and wherein the initial proposal for a possible implant placement is shown in a display; - a current spatial position of the virtual implant representation is determined by the processor as a final implant placement via a user input received at the processor, wherein the final implant placement is within the frame for possible implant placements . <EOS>