Comparative biomechanical testing of customized three-dimensional printing acetabular-wing plates for complex acetabular fractures

Background. Three-dimensional (3D) printing of an acetabular wing-plate is a new minimally invasive surgical technique for complex acetabular fractures. Objectives. To investigate the biomechanical stability of 3D printing acetabular wing-plates. The results were compared with 2 conventional fixation systems. Material and methods. Eighteen fresh frozen cadaveric pelvises with both column fractures were randomly divided to 3 groups: A - iliosciatic plates fixation system; B- 3D printing plates; C- 2 parallel reconstruction plates fixation system. These constructions were loaded onto a biomechanical testing machine. Longitudinal displacement and stiffness values of the constructs were measured to estimate their stability. Results. When the load force reached 700 N, Group A was superior to Group B in the longitudinal displacement of point 1 (p > 0.05). The longitudinal displacement of point 2 showed no significant differences among Groups A, B and C, and the displacement of the fracture line over point 3 showed no significant differences between Groups A and B (p > 0.05). The axial stiffness of Groups A, B and C were 122.4800 +/- 8.8480 N/mm, 168.4830 +/- 14.8091 N/mm and 83.1300 +/- 3.8091 N/mm, respectively. Group B was significantly stiffer than A and C (p < 0.05). Loads at failure of internal fixation were 1378.83 +/- 34.383 N, 1516.83 +/- 30.896 N and 1351.00 +/- 26.046 N for Groups A, B and C, respectively. Group B was significantly superior to Groups A and C (p > 0.05). Conclusions. Customized 3D printing acetabular-wing plates provide stability for acetabular fractures compared to intraspecific buttressing fixation.