| Objective: To simulate the reconstruction of popliteal tendons at different injured sites in post-stable TKA at 0° and 90° positions by three-dimensional technology,and to analyze the influence of reconstructed popliteal tendons on postoperative knee joint stability by finite element method.Methods: A healthy male volunteer was selected for knee CT scan,and the model was constructed and analyzed using Minnics,Geomatic,Soli Works and ANSYS:(1)After stable TKA,a knee joint model of Popliteal tendon(PT)was established.(2)According to the different fracture sites of the popliteal tendon(the joint of the popliteal ligament,the joint of the popliteal ligament with the lower side of the popliteal ligament,and the joint of the popliteal ligament with the lower side of the popliteal ligament),the reconstruction model of the popliteal tendon was established on the existing model according to the standard reconstruction surgery;(3)0° and 90° flexion models were established on the quadratic model,and the activity of the model in 6 directions(anterior and posterior tibial movement;Internal and external rotation of tibia;Tibial varus and varus),using Ansys software for finite element analysis.The results are as follows:1.Finite element model of knee joint reconstruction after 6 Tkas of PT injury at different positions was established.A)Reconstructed 0° and 90° knee joint models with ligaments,bone tissue,prosthesis and other structures strictly based on the anatomical structure of the knee joint.The 6 models were consistent with the anatomical structure characteristics of human knee joint.B)Femur prosthesis,tibial prosthesis and spacer were installed in accordance with the standard TKA operation method.According to literature data,material attributes and boundary conditions were defined for different model structures by Ansys 19.0 software,and six finite element models of knee joint after TKA were established after grid processing.C)On the knee joint model after TKA,the popliteal tendon fractures at different parts were reconstructed according to the popliteal tendon reconstruction surgery,and the finite element analysis of postoperative knee joint stability was performed at 0° and90° positions.2.Effects of different injury sites of reconstructed PT on postoperative knee joint stability in post-stable TKA.A)Reconstruction of the popliteal tendon junction after a(0)°TKA with 134 N forward force applied to the posterior proximal tibia(4.9142)<Reconstruction of popliteal tendon after TKA(4.9762);Reconstruction of the popliteal and fibular ligament after TKA(5.2613),and corresponding B(90°)were: reconstruction of the popliteal tendon after TKA combined with the subordinate(0.98579)<;Reconstruction of the popliteal tendon junction after TKA(1.0179)<Reconstruction of the popliteal fibular ligament after TKA(1.0741).Compared with normal knee data,knee motion increased at 0 degree after popliteal and fibular ligament reconstruction.There was no significant difference between the 90 degree position and normal knee motion in the reconstruction of three different parts of the knee.B)Reconstruction of the popliteal tendon junction at A(0)°TKA after 134 N backward force was applied to the anterior proximal tibia(0.4308)<Reconstruction of hamstring tendon after TKA(0.46593)<Reconstruction of the popliteal and fibular ligament after TKA(0.50475),corresponding to B(90°): reconstruction of the popliteal tendon after TKA combined with the subordinate(0.64069)<Reconstruction of the popliteal tendon junction after TKA(0.66699)<Reconstruction of the popliteal and fibular ligament after TKA(0.70825),there was no significant difference between 0degree and 90 degree position in the movement of the knee joint after reconstruction of different injured sites of the popliteus tendon.C)Reconstruction of the popliteal tendon junction after A(0)°TKA with 10 N inward force applied to the anterior proximal tibia(0.4308)<Reconstruction of hamstring tendon after TKA(0.46593)<Reconstruction of the popliteal and fibular ligament after TKA(0.50475),corresponding to B(90°): 0.64069 < combined with the subordinate popliteal tendon after TKA<Reconstruction of the popliteal tendon junction after TKA Reconstruction of the popliteal ligament after TKA 0.70825,there was no significant difference between 0 degree position and normal knee joint movement after reconstruction of different injured parts of the popliteus tendon.Movement in the 90 degree position was reduced after reconstruction of the popliteal tendon at different injury sites compared to the normal knee joint.D)Reconstruction of the popliteal tendon junction at A(0)°TKA after 10 N outward force was applied to the medial side of the proximal tibia(0.94351)<Reconstruction of hamstring tendon after TKA(0.99665)<Reconstruction of the popliteal and fibular ligament after TKA(1.2801),and corresponding B(90°)were: reconstruction of the popliteal tendon after TKA combined with the subordinate(0.734)<Reconstruction of the popliteal tendon junction after TKA(0.76192)<Reconstruction of the popliteal and fibular ligament after TKA(0.80942).After reconstruction,there was no significant change in 0 degree position movement compared with normal knee joint data.The 90 degree position reduced movement after reconstruction of injuries in different parts of the hamstring.E)Reconstruction of the popliteal tendon junction at A(0)°TKA after applying 10 n.m force inward to the proximal tibia(8.1978)<Reconstruction of the popliteal tendon after TKA(8.7523)<Reconstruction of the popliteal and fibular ligament after TKA(10.658),corresponding to B(90°): reconstruction of the popliteal tendon after TKA combined with the subordinate(3.8507)<Reconstruction of the popliteal tendon junction after TKA(4.0033)<Reconstruction of the popliteal and fibular ligament after TKA(4.2627),compared with normal knee joint movement,there was no significant change in the 0 degree position,while the postoperative knee joint movement was slightly reduced in the 90 degree position combined with the reconstruction of the popliteal tendon after TKA.F)Reconstruction of the popliteal and fibular ligament at A(0)°TKA after 10 n.m external force was applied to the proximal tibia(4.9924)<Reconstruction of popliteal tendon after TKA(5.0012)<Reconstruction of the popliteal tendon junction after TKA(5.0028),corresponding to B(90°): reconstruction of the popliteal tendon after TKA(5.1531)< Reconstruction of the popliteal tendon junction after TKA(5.3045)< Reconstruction of the popliteal and fibular ligament after TKA(5.6061).Compared with the normal knee joint,the movement of the popliteal and fibular ligament at the 0degree and 90 degree positions was reduced after reconstruction of three different parts of the injury.At 90 degrees,movement is significantly reduced.Conclusion: after TKA for popliteal tendon injury from different parts of the reconstruction,from 0 degrees and 90 degrees are moved forward,backward,varus and valgus,spin,spin six direction compared with the normal knee stability shows:reconstruction after 90 degrees,spin,spin,varus and valgus four direction activity is limited to different extent,limited rotary activities outside the most obvious;Good stability of forward and backward movement;After reconstruction of different parts of the popliteal tendon,the stability at 0 degree position in six directions was good.Therefore,for patients with popliteal tendon injury after TKA,reconstruction is an option to ensure the stability of knee joint after TKA.However,it has also been found from experiments that reconstruction of popliteal tendon injury at different parts has certain limitations on the activity of knee joint at the 90 degree position.Through three different damage parts reconstruction results,select popliteal tendon and popliteal ligament reconstruction at the same time or popliteal ligament reconstruction of postoperative knee 90 degrees alone activity compared to the limited popliteal tendon reconstruction alone is better,the reconstruction is necessary,especially for patients with small daily knee joint mobility,can guarantee the stability of postoperative knee joint. |
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