In bone drilling process during the surgical operations, heating increases extremely due to undesired temperature rise that sometimes seriously damages the bones and soft tissues. The overheating is usually recognized as the temperature exceeds 47 °C known as a critical limit above which the drilling causes osteonecrosis. In this study, a new driller system is developed to prevent the overheating in orthopedic surgical applications. The driller system has a closed-circuit cooling system to reduce the undesired temperature rise during the bone drilling process. The driller system is designed and manufactured as a prototype and tested experimentally in vitro by drilling fresh bovine bones using different processing parameters. A drill bit with a diameter of 10 mm is designed with a closed-circuit cooling channel internally and used in the bone drilling tests. In the drilling tests, the temperatures levels of the bones are measured using both non-contact and thermocouple sensors. Based on the results measured in the experiments, the developed driller system provides a valuable temperature reduction during the bone drilling process. Therefore, the bone temperature reduction was measured range of 20–25 % for lower spindle speeds (rpm) that is usually preferred by surgeons. The temperature levels measured from the drilling tests of the developed driller system having a cooling system are compared with the use of regular bone drilling process without cooling. A valuable temperature reduction is obtained using the driller system during the bone drilling tests.

In this research, biomechanical behaviors of five different configurations of screws used for stabilization of femoral neck fracture under axial loading have been examined, and which configuration is best has been investigated. A point cloud was obtained after scanning the human femoral model with a three dimensional (3-D) scanner, and this point cloud was converted to a 3-D femoral model by Geomagic Studio software. Femoral neck fracture was modeled by SolidWorks software for five different configurations: dual parallel, triple parallel, triangle, inverted triangle and square, and computer-aided numerical analysis of different configurations were carried out by ANSYS Workbench finite element analysis (FEA) software. For each configuration, mesh process, loading status (axial), boundary conditions and material model were applied in finite element analysis software. Von Mises stress values in the upper and lower proximity of the femur and screws were calculated. According to FEA results, it was particularly advantageous to use the fixation type of triangle configuration. The lowest values are found as 223.32 MPa at the lower, 63.34 MPa at the upper proximity and 493.24 MPa at the screws in triangle configuration. This showed that this configuration creates minimum stress at the upper and lower proximity of the fracture line. Clinically, we believe that the lowest stress values which are created by triangle configuration encompass the most advantageous method. In clinical practices, it is believed that using more than three screws does not provide any benefit. Furthermore, the highest stresses are as follows: at upper proximity 394.79 MPa in triple parallel configuration, for lower proximity 651.2 MPa in square configuration and for screw 2459 MPa in inverted triangle.