Finite element analysis on anterograde screw fix of anterior column of acetabulum / 中华骨科杂志

ABSTRACT

Objective To explore the optimal screw fixation of anterior column lag screw fixation in the treatment of acetabular anterior column fractures by finite element method.Methods Firstly,CT scanning images from one healthy adult volunteer (male 30),were transferred into Materialise Mimics Innovation Suite 16.0 software,then three-dimensional (3D) models of pelvic were reconstructed and stored in stereolithography format.Then Imageware 12.0 software (EDS,USA) was used to produce the optimal and safe channel of the screw for acetabulum anterior column fixation.Three types of screw fixation were generated,i.e.(1) geometric algorithm screw channel,(2) in-out-in channel,(3) free screw channel.Secondly,all model data were transferred into Ansys 12.0 software to establish the finite element model.Gravity load were defined as 600 N,1 200 N,and 2 400 N,and the Von Mises the parameters of peak stress and deformation were recorded.Results Respectively load of 600 N,1 200 N,2 400 N force to normal hip and geometric algorithm screw channel, in-out-inscrew channel,free screw channel,the comparison between groups of hip by stress and hip deformation,with a given loading force of hip by stress and hip deformation increase gradually,the two were positively correlated,including screw by stress at slightly higher than that of normal hip,while the stress of hip by geometric algorithm screw channel andin-out-inscrew channel were similar,and that by free screw channel increased significantly.There was no significant difference between groups in the hip deformation.With a given loading force (600 N,1 200 N,2 400 N) on geometric algorithm screw channel、 in-out-inscrew channel and free screw channel,the deformation is gradually increased,and there were positively correlated.With the stress on geometric algorithm screw channel,it was significantly reduced compared with the latter two,and in-out-in screw channel suffered the biggest stress.Conclusion Through the finite element analysis,the geometric algorithm screw channel can be used as a safe and effective way for acetabulum anterior column fracture.