Fig. 4A–B.

A preoperative virtual simulation of joint-preserving tumor resection and prosthetic reconstruction using CAD software is shown for Patient 7 with right distal femur osteosarcoma at the metaphysis. (A) A diagram shows an anterior view of the 3-D bone model generated from the preoperative CT image data set. The 3-D model and reformatted views of CT images are manipulated and analyzed. The level and orientation of proximal and distal resection are marked, based on the MR measurements of the tumor extent with reference to the joint line. The simulation project file of the CAD software is then transferred to implant engineers who design a CAD prosthesis with the exact dimensions as decided by the surgeons. (B) The final design of CAD prosthesis (orange in color) is imported back to the original simulation file and a final check of the design before approval to manufacture is made.