چكيده به لاتين
Osteoarthritis of the knee is one of the most common and disabling joint disorders. Among various treatment methods, one highly effective and non-invasive approach is the use of joint-contact force-reducing orthoses. The use of these orthoses can lead to a reduction in patient pain, consequently increasing activity and improving quality of life. Given the importance of patellofemoral joint osteoarthritis and the lack of advanced orthoses to reduce contact forces in this joint, both nationally and globally, scientific design and analysis of such a device were conducted in this study. The factor generating forces on the patellofemoral joint is the pressure on the patellofemoral joint, the force exerted by the quadriceps muscle, and the subsequent tensile force on the patellar tendon. Therefore, in the orthosis design, a mechanism parallel to the quadriceps muscle with the same function was designed to reduce the activity of this muscle. Subsequently, the effect of the designed orthosis on improving knee joint function was investigated through biomechanical analyses in the OpenSim software. For this purpose, orthosis modeling was initially performed as an operator with specific mechanical properties in the software environment. Then, simulation and analysis of squatting and walking movements were carried out using a valid musculoskeletal model and laboratory motion analysis data related to an individual with specific physical characteristics.As a result, a 60% reduction in patellofemoral joint pressure force was reported for an individual with a weight of 66.6 kg, using an orthosis with a stiffness of 10000 N/m in a squatting motion at a 90-degree flexion. Finally, to reduce hamstring force during walking, the mechanism of the device was modified, and an automatic system for adjusting the operator's stiffness was added. Further, for a detailed observation of the performance of the designed mechanism and the examination of the requirements for proper assembly of components, the initial prototype of the mechanism was 3D-printed, and the mechanism was assembled on the body of a three-point corrective pressure orthosis. Additionally, to ensure the strength of the orthosis and the proper selection of its constituent materials, finite element analysis was conducted to examine the stresses imposed on the main components of the mechanism, orthosis body, and connecting elements. The results were compared with the strength values of each, and ultimately, the safety of the designed structure was confirmed.
