Finite element modeling and comparison of fixation methods for acetabular fracture with involvement of the quadrilateral plate

Objective To compared different fixation methods for acetabular fractures involving the quadrilateral plate using a finite element model of the acetabulum.Methods A model of acetabular fractures with quadrilateral plate involved was developed in the finite element software and processed in Hypermesh V10.0 to generate internal fixation with dual-column titanium plate (Group A),anterior special titanium moulding plate plus quadrilateral screws (Group B),and anterior special titanium moulding plate plus quadrilateral screws combined with posterior column screws (Group C).Pelvic stress in sitting and standing positions were simulated in sequence with constraint of tuber nodes and inferior femur.Maximum stress and displacement of the acetabulum and displacement of nodes on fracture lines were measured after a force of 600 N was applied to S1 verterbrae in line with the direction of gravity in sitting and standing positions.Results In sitting position,the maximum stress and displacement of the acetabulum exhibited a sequence of Group C (9.47,1.08) ＜ Group B (19.84,1.11) ＜ Group A (29.73,1.14).Moreover,the same result was found in standing position with Group C (9.62,1.09) ＜ Group B (12.18,1.10) ＜ Group A (13.28,1.13).Mean displacement of nodes on fracture lines ranked in order of Group C ＜ Group B ＜ Group A (P ＞ 0.05).Conclusions The finite element model can reflect the distribution of pelvic stress effectively.Anterior special titanium moulding plate plus quadrilateral screws combined with posterior column screws provide favorable biomechanical stability in treatment of acetabular fractures involving the quadrilateral area. Key words: Acetabulum ;  Fracture fixation, internal;  Finite element analysis