OBJECTIVE: To present a 2D computer model simulating a pediatric femur fracture treated with steel and titanium elastic nails, using the Finite Element Method, with a comparative evaluation of the paths and distribution of stresses, main stresses, and strains. METHODS: Two different models were used, both generated by application Ansys®, considering the simulation of a 1 mm transversal fracture of the diaphysis whose stabilization was performed with the use of intramedullary nails made of different materials (steel and titanium), according to the Mechanostat Theory proposed by Frost in 1987. RESULTS: The introduction of intramedullary nails in the femur has changed the path of stresses, and conducted compressive stresses. In the comparison, the model with titanium nails, according to the Mechanostat Theory proposed by Frost, presented a more homogenous performance in the strain study than the stainless steel nails. CONCLUSIONS: The model proposed attained the objective of comparing stresses and strains between the steel and titanium nails simulations. By analyzing the path and the distribution of stresses in the model (Von Mises and main stresses), one can see the qualitatively improved biomechanical behavior in the titanium nails model, but in the quantitative analysis restricted to the fracture focus regions, the values are statistically similar. In the strain study, the more homogenous biomechanical behavior is seen in the model with titanium nails, as all strains seen in fracture focus regions are within the physiological window proposed by Frost.
Fracture fixation, intramedullary; Bone nails; Image processing, computer-assisted; Finite element analysis; Comparative study
