Figure 2: Images from the patient shown in Figure 1. (a) Target resection planes have been designed according to the osteosarcoma (red) with a safe margin. The green zone is included between the two planes. A 5 mm distance (margin) between the plane and tumor was selected to spare epiphysis, whereas a 10 mm margin was chosen distally. K-wires are represented by green cylinders. A PSI was created to guide the saw blade and to respect the planes. (b) PSI has been postitioned at the surface of the exposed tibia, and the surgical saw has been placed on the PSI to follow the target planes.