Does an infra pectineal plate alone provide adequate fixation in anterior column posterior hemitransverse acetabular fractures? A comparative biomechanical study

BACKGROUND: The purpose of this study is to compare biomechanical properties of suprapectineal (SP) plate fixation, infrapectineal (IP) plate fixation, and both SP and IP plate fixation in anterior column posterior hemitransverse (ACPHT) fractures of the acetabulum using posterior and anterior column screws. METHODS: In 21 hard plastic left hemipelvis models, ACPHT fractures of the acetabulum were created, and in three different fixation groups, the methods were compared: Group 1: SP plating using a 3.5 mm reconstruction plate and cortical screw fixation, Group 2: Infrapectineal plating using 3.5 mm reconstruction plate and cortical screws combined with posterior and anterior column screws, and Group 3: Combined fixation with SP and IP plating using 3.5 mm reconstruction plates and cortical screws. Maximum load to failure (strength) of these three groups was compared between groups. RESULTS: The mean maximum load of failure for three groups was 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. CONCLUSIONS: The combined application of SP and IP fixation provides the most stable fixation of the ACPHT acetabular fractures, and IP fixation does not provide comparable biomechanical stability despite reinforcement with three-column screws placed away from the plate. Although IP fixation supported by anterior and posterior column screws with the limited combined approach is less invasive approach for patients, SP fixation should be included in the surgical treatment method to ensure adequate stability.