## 3 Results  
In this study, three cannulated screws were used for the stability and rigidity of FNFs. The positions of the fracture line (Pauwels angle) and cannulated screws (Rotation, Translate 1, Translate 2 and Translate 3) were determined as input parameters. Equivalent von Mises stress values on the fracture line surface and on each screw were determined as output parameters. In this study, first, a static analysis of the system (Figure 2c) was carried out by taking the average values of the input parameters (Table 2). Afterwards, the graphs of the desired output parameter values were analyzed, and the appropriate input parameters were selected according to the minimum equivalent stress values at the screw and fracture site. In this study, the importance of the Pauwels angle input parameter is slightly more prominent than that of the others. Figure 3 shows the behavior of the input parameters according to the equivalent stress values formed on the fractured surfaces with 3D graphs. The effects of the Input parameters Rotation and Translate 1, 2, and 3 on the stresses at the fracture surfaces are weak. On the other hand, the effect of the Pauwels angle on the stress values on the fracture surfaces is significant (Figure 3). When the effectiveness values of the input parameters are analyzed and the stability of FNFs is considered, it is thought that the second important output parameter is the equivalent stresses in the screws (Figure 4). Four input parameters that determined the position of the screws were determined. These are the linear distance of each screw from the center outwards (Translate 1, 2 and 3) and the angle of each screw with the horizontal axis (Figure 1). Equivalent stress values on the screws under the variation in Translate 1, 2 and 3 parameters are given in Figure 4. In addition, to observe the effect of the input parameter Rotation, this value was set between 0\({}^{\circ}\) and 60\({}^{\circ}\). These two values were chosen because they form the normal triangular position and the inverted triangular position of the screws. In addition, the average position of the Pauwels angle during these operations was chosen (54\({}^{\circ}\)) (Figure 5). When Figure 4 is analyzed, it is seen that the change in Translate values in all three screws had no effect on the equivalent stresses on screw 1, and the stress value is constant at approximately 80 MPa. In addition, it was found that the effect of the change in Translate values on the equivalent stresses on screws 2 and 3 was significant. When the changes in stress values on screw 2 are analyzed in both graphs, it is seen that the graph in Figure 4a is convex and the graph in Figure 4b is concave. When both graphs are analyzed, it is seen that the stress values on screws 1, 2, and 3 intersect in a certain region. These areas correspond to the regions where the stress values are low. The common Translate values of all three screws in these regions varied between 6.5 mm and 7.5 mm. These data inform us that it would be appropriate to send all three screws at a distance of 7 mm because the common areas of the graphs of all three screws correspond to this region. When the screws are evaluated alone, it is seen that the Translate values according to the lowest equivalent stress are different. But triple screws used in the treatment of femoral neck fractures should be considered together and they should share the stresses. Therefore, the Translate value was determined approximately. The effect of the Pauwels angle on the equivalent stresses in the screws is shown in Figure 5. In Figure 5a, the common Translate distance of the screws from the center is 7 mm, and the common Rotation angle is 0\({}^{\circ}\). In Figure 5b, the distance from the center is 7 mm, and the Rotation angle is 60\({}^{\circ}\). In Figure 5a, it is observed that the stress values on screw 2 are at very extreme points. In Figure 5b, the stress values on all three screws intersect with each other.