Rib implant failure frequently occurs in current rib replacement implants following tumor resections. The aim of the CAMED project was to develop rib implants lasting significantly longer than current designs which have a failure rate of 85% within one to three years after surgery [1]. The main idea was to develop implants that mimic the stiffness of a natural rib, thus not changing the biomechanical behaviour of the thorax. To achieve this goal a biomechanical model of the human thorax was built accounting for all relevant structures such as bones, costal cartilage, vertebral discs, and the costo-vertebral joints. In addition, the contributions of the passive stiffness of intercostal muscles, the pleura, and the skin are investigated. Within this project, also the stiffness of the costal cartilage [2] and the costo-vertebral articulations [3] were measured in fresh human cadavers in order to develop the FEM model. For verification purposes, the deformation of the human thorax FE-model was compared to measured deformations on human thoraces. The loading of the thorax model was done with fatigue loading (activities of daily living such as breathing), and maximum load cases (coughing, lying on the side, resuscitation…). A novel implant design using 3D printed PEEK has been developed by adjusting the implant cross-section to meet the bending and torsion stiffness of the resected rib. The simulation model is able to mimic the natural stiffness of the thorax by using highly nonlinear assumptions including geometric and material nonlinearities as well as orthotropic material models and contact definitions. The work was funded and supported by the Austrian Research Promotion Agency (FFG) within the K-project CAMED “Clinical Additive Manufacturing for Medical Applications”