Thermal analysis of orthogonal cutting of cortical bone using finite element simulations

Bone cutting is widely used in orthopaedic, dental and neuro surgeries and is a technically demanding surgical procedure. The major concern in current research is thermal damage of the bone tissue caused by high-speed power tools, which occurs when temperature rises above a certain tissue threshold value that is called bone necrosis. Hence optimization of cutting parameters is necessary to avoid thermal necrosis and improve current orthopaedic surgical procedures. In this study a thermo-mechanical finite element model of bone cutting is presented that idealizes cortical bone as an equivalent homogeneous isotropic material. Maximum temperature on the bone was found in the region where the thin bone layer (chip) was separated from the bone sample that was adjacent to the tool rake (i.e. front face of the tool) Temperature values were calculated and compared for cutting conditions with and without coolant (irrigation). The influence of bone thermal properties on the depth of thermal necrosis was discussed. The simulated cutting temperatures were compared with experimental results obtained from bone drilling tests. The cutting processes identified critical variables and cutting parameters that influence the thermo-mechanics of bone cutting.