APPLICATION OF «LIRA» SOFTWARE COMPLEX FOR RESEARCH OF ANTERIOR CRUCIATE LIGAMENT STRESS

Anterior cruciate ligament injury (ACL) is one of the most frequent and severe injuries of the knee joint. Despite the fact that surgical treatment of patients with ACL rupture today is the "gold standard" in orthopedic surgery, patients with this type of trauma face such problems as long-term loss of incapacity and incomplete return to the previous level of physical activity. Another important factor is the early development of knee osteoarthritis both after ACL reconstruction and in the case of chronic anterior instability without surgery. An enlarged posterior tibial slope is considered a potential risk factor for ACL graft rupture. Biomechanical studies of the knee joint showed that the angle of the tibial plateau is an important factor that ensure stability of the knee joint. Aim. Analyze influence of different posterior tibial slope angles on anterior cruciate ligament stress efforts. Conclusion. The obtained results of calculations indicate that with an increase of posterior tibial slope the effort stress in anterior cruciate ligament also increase. At the angles of posterior tibial slope (α = 0°, α = 5°, α = 15°), the increase in effort stress didn't exceed 15%. However, we note that the calculation was performed without taking into account the dynamic effect, in which the applied loads, and as a result, the forces can increase several times. With the considered load cases, the forces are higher in the model without taking into account the axial loads. In this case, the difference in the increase of the forces is higher about 2 times for the second variant of loading. Preliminary calculations have shown that the magnitude of the effort stress depends on a variety of factors, such as the size of the model, the attachment points of the ligaments, the properties of the objects being modeled, and the loading scheme. These factors can be taken into account when using universal software packages.