Three-dimensional Finite Element Analysis Of Different Degrees Of Bone Defect In The Proximal Tibia Combined With Cemented Plate Internal Fixation

Objective:The finite element analysis method was used to investigate the risk of fractures of bone defects in different degrees of proximal tibia and the stress after internal fixation,which provided a theoretical basis for the selection of appropriate internal fixation for clinical treatment.Methods:A healthy male volunteer was selected to complete the three-dimensional finite element model of the tibia using CT scan and three-dimensional finite element software.1 Select the point at the anterior aspect of the tibia and 25 mm below the tibial plateau,and establish the hemispherical defect models A1,A2,A3,and A4 by using the diameter of 1/5,2/5,3/5,and 4/5 of the coronal diameter at that point.2 Fill the bone cement repair to the defect respectively to obtain the models B1,B2,B3,and B4.3 On the basis of the B-type model,the locking steel plates are respectively fixed,and the models C1,C2,C3,and C4 are obtained.The finite element analysis of each model was carried out by applying the load to the axis of the tibial plateau during normal human walking.Results:In the complete tibial model,the maximum stress of M was 49.20 MPa.In the simple bone defect group,the maximum stress of A1 and A2 was less than the yield strength of 125 MPa,the safety factor FOS > 1,the fracture risk was small.The maximum stress of A3 was greater than 125 Mpa,FOS < 1,and the fracture risk was higher.The maximum stress of A4 was 214.45 MPa,which exceeded the ultimate strength of 178.7 MPa,FOS < 0.7,and the fracture risk was great.The maximum stress values of B1 and B2 were less than 125 MPa in the cement-filled group.The maximum stress of B3 and B4 groups still exceeded the yield strength,and there was still a risk of fracture.The maximum stress of C1,C2,C3 and C4 did not reach the yield strength and the risk of fracture was small.Conclusion:For the proximal tibia bone defect <3/5 coronary diameter,it can only be used for bone cement filling repair.For bone defects ≥ 3/5 coronary diameter,it must be combined with the locking plate internal fixation on the basis of bone cement filling.