engleski

Improved inverted triangle configuration design in treating high-angle femoral neck fracture using finite element analysis

Pauwels classification of femoral neck fractures is based on the vertical orientation of fracture line, with Pauwels type III fracture being the most unstable. In order to avoid complications, open anatomic reduction and stable internal fixation remain the optimal treatment option for younger patients. Aim was to determine the biomechanically optimal screw configuration between control and test models and create the framework for design of osteosynthesis materials based on geometrical characteristics. A CT scan of a synthetic femur was carried out in order to create a 3D model and perform a finite element method simulation. Inverted triangle configuration used as a control group was compared to the x- crossed screw configuration. Modulus of elasticity of bone amounted to 17 GPa for cortical bone and 1.1 GPa for trabecular bone. Grade 5 titanium screws with a modulus of elasticity of 110 GPa were chosen. Friction coefficient on the fracture site totaled 0.2. Forces ranging from 600 to 1600N were applied vertically on the femoral head. Inverted triangle configuration showed maximum von Mises stress of 58.0 MPa and 158.7 MPa, maximum femoral head displacement of 4.183 mm and 11.7 mm and relative fracture displacement of 0.0378 and 0.1032 at 600N and 1600 N, respectively. Maximum von Mises stress of 53.6 MPa and 142.8 MPa, femoral head displacement totaling 4.029 and 10.19 and relative fracture displacement of 0.0276 and 0.0963 were seen in an x-crossed configuration model at 600N and 1600N, respectively. The newly proposed x-crossed screw configuration displays superior biomechanical properties, such as the ability to resist higher von Mises stress and a smaller degree of fracture and femoral head displacement. Further studies, as well as biomechanical experiments with different parameters are needed in order to arrive to a definitive conclusion.

inverted triangle ; finite element analysis ; femoral neck fracture ; von Mises ; displacements

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