Biomechanical evaluation of three kinds of internal fixation methods for acetabular quadrilateral area fracture

Objective The purpose of this study was to evaluate the best internal fixation methods of acetabular quadrilateral area fracture.Methods The quadrilateral area fracture models were created by 12 males hemipelves specimens,divided into three groups randomly.The fractures were treated respectively with the following internal fixaction methods,infrapectineal buttress reconstruction plate(group A),infrapectineal buttress locking compression plate(group B),reconstruction plate combined with trans-plate quadrilateral screws(group C).Then the willow leaf films were stuck on the femoral head and vertical compressing loading was continued via the fracture models,followed by measurement of physiological weight 600 N on intact acetabulum in group Ⅰ(No fracture line was made) and internal fixation of acetabular dome contact characteristics and horizontal and vertical displacements in A,B,C groups.Results Under physiological weight of 600 N,acetabular dome contact characteristics in three groups failed to return to normal,There was a significant difference on the loading area,the mean pressure,the peak pressure,horizontal displacements and longitudinal displacements among groups(P0.05,besides 200 N).With loads increasing,horizontal displacements and longitudinal displacements were larger,and under 1800 N the longitudinal displacements of group A reached failure criteria.Conclusions For the acetabular quadrilateral area fracture,the internal fixation stability and contact characteristic of reconstruction plate combined with trans-plate quadrilateral screw metho is w better than infrapectineal buttress plate,and it can reduce incidence rate of traumatic arthritis.