The Finite Element Analysis To The Treatment Of Double Locking Plate In Fixation Of The Femoral Shaft Fractures And Preliminary Observation Of Clinical Efficacy

Background: Femoral shaft fracture is one of the most common fractures,although most of them can be cured by standard treatments, there are still some nonunion cases which will occur due to various reasons. Nonunion is a main complication of femoral shaft fractures,it can lead to pain,loss of function,deformity and a series of other complications. By far there are many treatments for nonunion after femoral shaft fracture, including: intramedullary nail dynamization, reamed nail exchange, plate augmentation with retention of intramedullary nail, double locking plate and Ilizarov external fixation, etc. But there are still some relatively problems such as insufficient blood supply, shortening of lower limbs, low union rate, limited indications and so on need to be solved.Objective: In this study, using the methods of finite element analysis, we tend to compare the biomechanical quality of single lateral plate(SLLP), two different angles of double plate( 180°、90°)(180DLP、90DLP) and medial plate attached with intramedullary nail (MIN) which could provide biomechanical evidence to the clinical treatment and postoperative rehabilitation.Methods: 1 .Reconstruction of artificial femur three-dimensional model, and the establishment of femoral shaft nonunion model. 2.The establishment of a single lateral plate, double locking plate with two different angles (180°、90°) and medial plate attached with intramedullary nail model. 3 .Match the fracture model and internal fixation model, triangular mesh meshing, material assignment and other finite element pre-processing process. 4.Model assembly, contact surface definition, set the boundary conditions and load, the finite element simulation biomechanical analysis.5.Interpretation of the finite element analysis data. 6.Clinical preliminary observation.Results: 1.The maximum stress values of the four fixed models are: SLLP>MIN>90DLP> 180DLP. SLLP model maximum stress value of 2506Mpa, MIN model maximum stress value of 1945Mpa, 90DLP model maximum stress value of 1001 Mpa,180DLP model maximum stress value of 324Mpa. 2.The varus stability of the four kinds of fixed models is as follows: 180DLP> MIN> 90DLP> SLLP. The angle of fracture was 0.4 ° and the internal fixation angle was 0.8° in 180DLP model. The angle of fracture was 0.9° and the internal fixation angle was 0.8° in MIN model. The angle of fracture was 2.7° and the internal fixation angle was 3.2° in 90DLP model. The angle of fracture was 11.3° and the internal fixation angle was 14.9° in SLLP model. 3.The stability of rotation under four fixed models is 180DLP> 90DLP> MIN= SLLP.180DLP model under the rotation angle of 0.2 °, 90DLP model under the angle of rotation of 0.9°, MIN model under the rotation of 1.2°, SLLP model rotation angle of 1.20°Conclusions: 1.180DLP model is superior to other internal fixation methods in the treatment of femoral shaft nonunion. In stress values and rotation stability aspect, 90DLP is better than MIN; in varus stability aspect, MIN is better than 90DLP. We infer that the two in the treatment of femoral nonunion on the effect is similar. 2. The fixation of double locking plate is characterized by high healing rate and low complication rate,especially suitable for the lack of medial support with large bone defects in patients with femoral nonunion.