Is an Anatomical Suprapectineal Quadrilateral Surface Plate Superior to Previous Fixation Methods for Anterior Column-Posterior Hemitransverse Acetabular Fractures Typical in the Elderly?: A Biomechanical Study.

Background: This study aimed to compare the mechanical characteristics of four fixation methods including an anatomical suprapectineal quadrilateral surface (QLS) plate in hemipelvic models of anterior column-posterior hemitransverse acetabular fractures typical in elderly patients.

Methods: In total, 24 composite hemipelvic models were used and allocated to four groups: group 1, pre-contoured anatomical suprapectineal QLS plate; group 2, suprapectineal reconstruction plate with two periarticular long screws; group 3, suprapectineal reconstruction plate with a buttress reconstruction plate; group 4, suprapectineal reconstruction plate with a buttress T-plate. Axial structural stiffness and displacement of each column fragment in four different fixation constructs were compared.

Results: Multiple group comparisons of axial structural stiffness demonstrated significant difference ( = 0.001). Although there was no significant difference between groups 1 and 2 ( = 0.699), group 1 showed greater stiffness than groups 3 and 4 ( = 0.002 and 0.002, respectively). Group 1 showed less displacement in the anterior region of the anterior fragment than group 4 ( = 0.009) and in the posterior region than groups 3 and 4 ( = 0.015 and = 0.015, respectively). However, group 1 demonstrated greater displacement than group 2 in the posterior region of the posterior fragment ( = 0.004), while showing similar displacement to groups 3 and 4.

Conclusions: The anatomical suprapectineal QLS plate provided the mechanical stability comparable or superior to other existing fixations in osteoporotic models of anterior column-posterior hemitransverse acetabular fractures typical in the elderly. However, additional plate modification would be needed for better stability and outcomes.