Biomechanical comparison of different fixation in anterior column posterior hemitransverse fractures of the acetabulum

The purpose of this study is to compare biomechanical properties of suprapectineal (SP) reconstruction plate osteosynthesis, infrapectineal (IP) plate fixation combined with posterior and anterior column screws and both suprapectineal and infrapectineal plate fixation. In 21 hard plastic left hemipelvis models, anterior column posterior hemitransverse (ACPHT) fractures of the acetabulum were created, and in three different fixation groups, the methods were compared. Group 1: SP plating by using a 3,5 mm reconstruction plate and cortical screw fixation. Group 2: IP plating by using 3,5 mm reconstruction plate and cortical screws combined with posterior and anterior column screws. Group 3: Combined fixation with SP and IP plating by using 3,5 mm reconstruction plates and cortical screws. The strength of these three groups was evaluated with biomechanical analysis, and the results were statistically compared. The average load of failure for three groups were 2921 N, 2018 N and 3658 N, respectively. When strength was compared considering the force that causing implant failure, it was determined that the strongest fixation was achieved when SP and IP fixation method were applied together, followed by SP only fixation and IP fixation supported by anterior and posterior column screws respectively. In conclusion, we found that the combined application of SP and IP fixation provides the most stable fixation of the ACPHT acetabular fractures, followed by SP only fixation and that IP fixation supported by posterior and anterior column screw application alone is insufficient. Although IP fixation supported by anterior and posterior column screws with the limited combined approach is less invasive, SP fixation should be included in the surgical treatment method to ensure adequate stability.