| Objective: The finite element analysis software was used to simulate the knee flexion and extension process of knee joints at different femoral prosthesis positions after TKA.The data of the tension of the medial and lateral collateral ligaments were collected to investigate the effect of the position of the femoral prosthesis on the tension of the medial and lateral collateral ligaments.Methods: 1.Construction of three-dimensional finite element model of knee joint after TKACT and MRI scans were performed on the knee joint of a healthy volunteer.The 3D model of the knee joint was reconstructed using 2D image data.The 3D model of the PS prosthesis was constructed by reverse engineering technique.In accordance with the standard of TKA bone cutting mode,the simulation technique was used to bone cutting and prosthetic installation in the ideal position of femoral prosthesis and deviating from the ideal position.According to literature research data,we defined boundary conditions,material properties and the corresponding load,including the knee joint bone,ligament and various parts of the prosthesis.2.Effect of femoral prosthesis position on tension of medial and lateral collateral ligamentThe finite element analysis of the flexion and extension process of the knee joint model with different femoral prosthesis positions was performed.The changes of the tension of the medial and lateral collateral ligaments were observed and the correlation analysis was performed.Results:1.Construction of three-dimensional finite element model of knee joint after TKA(1)A three-dimensional model of the knee joint including the skeletal,medial and lateral collateral ligaments,and patellar ligament was constructed,and the marker points and marking lines conforming to the anatomical characteristics of the Chinese people were determined,and the lower limb force lines were established according to the individual conditions.(2)A complete artificial knee joint PS prosthesis geometry model was constructed.(3)A three-dimensional finite element model of the knee joint after TKA was established with the ideal femoral prosthesis position and the deviation from the ideal position.2.Effect of femoral prosthesis position on tension of medial and lateral collateral ligament(1)When the femoral prosthesis was in the ideal position,the MCLand LCL tension changes during knee flexion are basically equal(the difference is less than 0.05N).(2)When the position of the femoral prosthesis was elevated to1.5mm,3.0mm,4.5mm,6.0mm,the difference in tension between MCL and LCL during knee flexion was similar to the ideal position.When it was elevated to 7.5mm,the change trend is opposite to the ideal position.When the position of the femoral prosthesis was moved down,the difference of MCL and LCL tension during knee flexion was significantly increased compared with the ideal position,and there is no significant correlation with the distance of the downward movement.(3)When the position of the femoral prosthesis was moved forward,compared with ideal position,the difference between the changes of MCL and LCL tension increased during knee flexion,and it was positively correlated with the distance of advancement;when the femoral prosthesis was moved backward,compared with ideal position,the difference between the LCL and MCL tension changes during knee flexion and extension also increased,which was positively correlated with the backward movement distance.Conclusions: 1.The three-dimensional finite element model of knee joint after TKA was successfully constructed,which laid a foundation for studying the influence of the position of femoral prosthesis on the tension of the medial and lateral collateral ligament during knee flexion.2.The lowering or excessive forward or excessive backward movement of the femoral prosthesis position after TKA can increase the difference of the tension of the medial and lateral collateral ligaments,which affects the lateral stability of the knee joint after operation. |
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