| To study the biomechanical properties of the tibia Denis II fractures by studying different combined iliac screws,and to provide more stable screws and the basis for clinical use.Methods:A healthy male volunteer was selected and his pelvic three-dimensional computed tomography was imaged.The three-dimensional finite element method was used to simulate the tibiofibular fracture model through the pupil.The ligament condition attribute was ass-igned and the cartilage between the ankle joint and the interpubic cartilage was simulated.The length of the iliac hollow channel nail was 85mm and the diameter was 7.3mm.A different arrangement was used to fix the Denis II type tibiofibular fracture.The single-segment single screw fixation?denoted as S1?was performed in the humeral condyle.The humeral condyle was fixed with two screws?S1?.*2),the double-segment Sacral first vertebral body and the sacral vertebral body are each fixed by a screw?S1S2?,the two-segment Sacral first vertebral body two screws combined with the Sacral and sacral ver-tebral body single screw Fixed as?S1*2S2?.A 600N axial compression load was applied to the normal pelvic model and the four fixed pos-terior fracture models on the vertebral first vertebral body.The displacement of the tibia from the highest point of the tibia,the displacement of the fracture end,and the Sacral and screw were calculated.Stress and carry out a biomechanical comparison of its four fixed modes.Results:The direction of axial force conduction of the five pelvic models was transmitted from the Sacral to the bilateral tibia through the ankle joint and then to the top edge of the bilateral acetabulum.The displacement of the pelvis of the normal pelvis relative to the hig-hest point of the tibia was 0.0723786 mm.The maximum stress of the pelvis is 13.99 MPa.The pelvic model of the first vertebral body of the Sacral was fixed with a screw displacement of 0.118247 mm,the screw displac-ement was 0.132 mm,the maximum stress of the screw was 24.07 MPa,and the maximum stress of the pelvis was 18.90 MPa.The lateral displacement of the fracture end is sorted from S1*2?S2(4.653-3)<S1S2(4.685-3)<S1*2(6.624-3)<S1(9.297-3).The pelvic model of the first vertebral body with two screws fixed in the pelvis is the displacement of the tibia relative to the highest point of the tibia.0.110131mm,the screw displacement is0.120mm,the max-imum stress of the screw is 21.55MPa,and the maximum stress of the pelvis is 17.10MPa.The lateral displacement of the fracture end is sorted from S1*2?S2(1.636-2)<S1S2(1.778-2)<S1*2(6.406-2)<S1(6.861-2).The pelvic model of the humeral first vertebral body and the second vertebral body with a screw fixed to the highest point of the tibia is 0.0812962mm,the screw displacement is 0.083mm,the maximum stress of the screw is 17.35MPa,and the maximum stress of the pelvis It is 13.03 MPa.The lateral displacement of the fracture end is sorted from S1*2?S2(0.3681-1)<S1S2(0.3868-1)<S1*2(1.111-1)<S1(1.196-1).The first segment of the Sacral of the double segment was made of two screws.The second vertebral body of the Sacral was fixed with a screw.The displ-acement of the tibia relative to the highest point of the tibia was 0.0794934 mm,the screw displacement was 0.083 mm,and the maximum stress of the screw was 15.45 MPa.The maximum stress of the pelvis is 13.05 MPa.The lateral displacement of the fracture end is sorted from S1*2?S2(0.4974-1)<S1S2(0.0563-1)<S1*2(1.459-1)<S1(1.549-1).Conclusion:Single-segment fixation,whether it is a single screw fixation or two screw fixation stability,is much different than the normal pelvis stability.The stab-ility of the two-segment fixation is similar to that of the normal pelvis,but the double-segment three-screw fixation The stability of the pelvis is better than two screws.Strong screw fixation not only allows the patient to exercise in the early stage,but also reduces the incidence of nonunion,heterotopic ossi-fication,malunion and lower back pain caused by late bone inflammation. |
PDF Full Text Request