Biomechanical comparison of 4 plate internal fixation methods for simulated fractures of acetabular posterior column / 第三军医大学学报

ABSTRACT

Objective To evaluate the stability of 4 different methods of plate internal fixation for simulated posterior column fracture of the acetabulum.MethodsTwenty preserved cadaveric semipelvic specimens were divided into 4 groups randomly.Models of isolated posterior column fractures of acetabulum were established and then fixed with 1 of following 4 methods of plate internal fixation2 screws at the each end of plate(group A),3 screws at the each end of plate(group B),1 screw each side in the closest allowable hole to the fracture and 2 screws at the each end of plate(group C),and 4 screws on each side of the fracture(group D).Under vertical compression load of 3 times' body weight,the displacements of the fracture site were measured and the shear rigidity of different internal fixation methods were compared.ResultsThe displacements of the fracture site in Group A,B,C,and D were 4.68?0.35,2.80?0.25,2.12?0.11 and 1.58?0.17 mm respectively,with a decreasing trend from Group A to D.The shear rigidity of internal fixation methods in Group A,B,C,and D were 129.42?9.60,228.91?12.05,285.21?26.16 and 414.71?34.29 N/mm respectively,with an increasing trend from Group A to D.The differences of both displacements and shear rigidity between each 2 groups were significant(P