Three dimensional finite-element analysis of treating Vancouver B1 periprosthetic femoral fractures with three kinds of internal fixation

This study is to compare the stress distribution, maximum stress, stiffness and relative displacement of 3 different models of Vancouver type B1 fractures fixed with 3 kinds of internal fixation using finite element analysis. Finite element models of periprosthetic femoral fractures were reconstructed and fixed with 3 kinds of internal fixations. The internal fixations included double circle cable, traditional locking titanium plate and multidirectional locking plate of double-row screws, designed by the authors. Through establishing finite element models of Vancouver type B1 fractures, axial compression and torsion were simulated on different fixations. The von-Mises stress and total deformation distribution of femur, internal fixators and the fracture sites were investigated. Finite element analysis was performed for B1 periprosthetic fractures in both normal bone and osteoporosis models. Compared with double circle cable and traditional locking titanium plate of single-row screws, multidirectional locking plate device had higher stiffness, more even stress distribution and better stability under the same vertical and rotational loading. Smaller relative deformation and smaller maximum stress of prosthesis and fixation were found in the multidirectional locking plate system, which suggested that it is a more stable and stronger device than double circle cable and traditional locking titanium plate for Vancouver type B1 periprosthetic fractures. The multidirectional locking plate system is more stable and stronger than double circle cable and traditional locking titanium plate. It is expected to be an effective device in treating Vancouver type B1 fractures.