Biomechanical analysis of Magic screw fixation in the treatment of acetabular posterior column fractures

The biomechanical stability of Magic screw in the treatment of acetabular posterior column fractures was analyzed by finite element method. Based on the computed tomography (CT) and magnetic resonance imaging (MRI) data of volunteers, a three-dimensional finite element model of the pelvis was established and its validity was verified, and then a posterior column fracture model of the acetabulum was generated. Single plate, double plate in the posterior column and Magic screw were used for fixation, and the differences in biomechanical stability of the four fixation models were compared. A pressure of 500 N was applied to the upper part of the sacrum to simulate human gravity. The maximum stress of the retrograde lag screw, posterior column single plate, double plate and Magic screw fixation model in standing and sitting states were: 114.10, 113.40 MPa; 58.93, 55.72 MPa; 58.76, 47.47 MPa; 24.36, 27.50 MPa; the maximum stress at the fracture end were: 72.71, 70.51 MPa; 48.18, 22.80 MPa; 52.38, 27.14 MPa; 34.05,