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 (p = 0.001). Although there was no significant difference between groups 1 and 2 (p = 0.699), group 1 showed greater stiffness than groups 3 and 4 (p = 0.002 and 0.002, respectively). Group 1 showed less displacement in the anterior region of the anterior fragment than group 4 (p = 0.009) and in the posterior region than groups 3 and 4 (p = 0.015 and p = 0.015, respectively). However, group 1 demonstrated greater displacement than group 2 in the posterior region of the posterior fragment (p = 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.