Testing the effectiveness of Variable fixation screws against Standard locking screws in clinically relevant fractrure patterns: a finite element analysis.

The main purpose of this thesis project is the analysis of fixation device on a bone fracture. This device is a osteosynthesis screw called Variable Fixation Locking Screw (VFLS). The variable fixation effectiveness is tested in clinically relevant fracture patterns and it is compared with a standard one. The VFLS has a polymeric sleeve characterized by a specific degradation profile over time in order to allow micro-movement during the healing process of the bone fracture. The first step of this project was to validate the femur model, with no pathological condition, carried out in the previous work. Afterwards, the fracture gap has been reproduced and the model has been assembled with plate and screws. The first simulations has been done using only standard locking screw, changing the width of the fracture gap from 3mm to 8mm adding one 1mm at the time. Then the process has been repeated using VFLS changing the Young Modulus of the sleeves in order to emulated their degradation. At the end, the average displacement values have been compared.