Three-dimensional Finite Element Analysis Of Two Kinds Of Fixtion System In Adult Of Femoral Neck Fracture With Posteromedial Bone Defect

Objective: To compare the stability of the fixation with three hollow screw and DHS with anti-rotation screw in adult posteromedialbone defect femoral neck fracture,one particular type of femoral neck fracture, and provide theoretical basis for the clinical application in internal fixation treatment of this particular type of femoral neck fracture.Methods: A healthy male, age 44, weight 75 kg, with no disease at any side of the femur and hip joint or trauma history from CT image data, Chinese citizen was chosen. By CT scanning the bilateral femurs and using Mimics10.0,Geo Magic Studio11.0,Ansys14.0, related data was got to establish three-dimensional finite element model of adult posteromedial bone defect femoral neck fracture(left). Data of Kirschner wire、Hollow screw,External fixator of building three-dimensional finite element model were put into the model of left femoral neck fracture with posteromedialbone defect. After seting boundary and load conditions, we got the displacement distributing,displacement value,stress and stress value of femur,impalnts and fracture cross-section. and compared the stability of the two fixing system :three hollow screw and DHS with anti-rotation screw.Results: According to the 3-D FEA models of the posteromedialbone defect femoral neck fracture in adult fixing by DHS with anti-rotation screw and three hollow screw,and boundary condition and load conditions on three conditions in normal gait, DHS with anti-rotation screw fixation system’s femur got more stress than the three hollow screw,and the femoral neck conduction is lower.The displacement of DHS with anti-rotation screw fixation system’s implant is lower than the three hollow screw.The DHS with anti-rotation screw fixation system is better than the three hollow screw in different direction fracture cross-section(P< 0.05). Significant differences was observed between DHS with anti-rotation screw fixation system and three hollow screw fixation system.Conclusions: For adult posteromedial bone defect femoral neck fracture, the DHS with anti-rotation screw fixation system have more biomechanical advantages and lower revision rates than the three hollow screw fixation system in the femoral neck condution, the displacement of anti-rotation screw fixation system’s implant, and different direction fracture cross-section.