3D subject-specific subject specific modeling, finite element analysis and evaluation of biomechanics of the knee complex after anterior cruciate ligament reconstruction

• Κύριος συγγραφέας: Ρισβάς, Κωνσταντίνος
• Άλλοι συγγραφείς: Risvas, Konstantinos
• Γλώσσα: English
• Έκδοση: 2021
• Θέματα: Finite element analysis; Finite element model; Anterior cruciate ligament; Anterior cruciate ligament reconstruction; Knee joint anatomy; Ανάλυση πεπερασμένων στοιχείων; Πρόσθιος χιαστός συνδέσμος

The Anterior Cruciate Ligament (ACL) injury is one of the most common knee injuries during sports activities. Anterior Cruciate Ligament reconstruction (ACLR) is a surgical approach that has emerged as the golden standard treatment, where a graft is placed in the position of the torn ligament through tunnels that are drilled on the femur and tibia bones, close to the native ligament origin and insertion sites. Over the course of years, many ACLR techniques have been developed featuring a plethora of parameters like the number of the drilled tunnels, the tunnel positioning, the graft harvesting site, the graft pre-tensioning load and much more. To evaluate the results of each selected ACLR approach, follow up examination is required.The complex nature of these examinations and recent technological advances paved the way for computational biomechanics as an alternative and effective tool to the disposal of biomedical researchers. Finite Element Analysis (FEA) is a valuable modeling and simulation approach of computational biomechanics, that enables to capture the geometry and material effects on the response of the anatomical structures like the knee joint under various loading conditions. In this thesis, a workflow that generates subject-specific FEM models of the knee joint to assess knee biomechanics after ACLR is developed. The proposed pipeline includes modeling and simulation of all key steps of ACLR, from tunnel drilling to graft fixation. Furthermore, it provides simulation scenarios that represent daily life activities, such as gait, and clinical exams, such as the Lachman test, to evaluate the performance of the ACL reconstructed FEM knee models, laying the ground for performing "what if" scenarios in order to predict the effectiveness of the ACLR approach. In the confines of this work we evaluated the performance of Single and Double Channel, Anteromedial and Transtibial portal surgery techniques and the response of three different graft materials under various pre-tension loads and fixation angles in simulation scenarios representing the Lachman test and a gait trial. Despite the limitations regarding the FE models constraints and the inherent complex nature of FEM simulations, the present work provides the groundwork for developing an extended and fully featured ACLR modeling framework.