The aim of this project is to perform medical knee arthroplasty procedures more precisely and with fewer complications for patients. Drill-free markerless tracking is intended to replace additional installations in order to speed up the healing process and reduce the risk of infection. It should also be possible to display the calculated leg axis in the correct position and orientation during the operation using AR visualisation in order to ensure the precise installation of the implant. The scientific and technical challenges lie in the accuracy requirements of the 3D acquisition, the 3D models for the femur and tibia, the calculation of the leg axis and the visualisation. All technical units (cameras and visualisation systems) must be transformed into a superordinate coordinate system in which the patient's physical leg is also localised. The precise recording, calculation and visualisation is to be carried out using AI methods. In addition to covering a large working area of the overall system, a high update rate must be taken into account.