2023, Vol. 27 ›› Issue (13): 1999-2004

Finite element analysis of percutaneous reverse screw for treatment of superior pubic ramus fracture

Lu Hui1, 2, Xu Ling1, Jiang Daixiang1, 2, Wu Qimei3, Liu Rong1, 2, 4   

Abstract: BACKGROUND: Percutaneous screw fixation of pubic ramus is widely used in clinical practice, but the selection of screw insertion point is lacking in mechanical verification.   
OBJECTIVE: To investigate the biomechanical characteristics of different insertion points of percutaneous reverse screw for superior pubic ramus fracture by finite element method.
METHODS:   CT data of healthy volunteers were input into Mimics software for 3D reconstruction of the pelvis. 3-Matic software was used to divide the model of superior pubic ramus fracture, and percutaneous reverse screws with different insertion points were established to simulate the treatment of superior pubic ramus fracture. After material assignment by Mimics software, Ansys software was used to simulate the force of standing position with 600 N load on S1 vertebral endplate and to compare the mechanical stability.   
RESULTS AND CONCLUSION: (1) For the fracture of superior pubic ramus in area I, if the insertion point was located in the upper part, the maximum stress on the whole model and screw was lower than that on the lower part. The insertion point was located at the upper part and the lower part, and the maximum stress of the screw was 4.57 MPa and 10.50 MPa. The upper part was significantly lower than the lower part, and the upper part was recommended as the insertion point above the midpoint of the pubic crest. (2) For the fracture of superior pubic ramus in area II, the effect of the insertion point on the upper or lower part was similar. (3) For fractures of superior pubic ramus in area III, it is recommended to select the insertion point below the midpoint of the pubic crest.
Key words: percutaneous reverse screw, superior pubic ramus fracture, finite element analysis, insertion point, biomechanics