3D-DIC in the service of orthopaedic surgery: Comparative assessment of fixation techniques for acetabular fractures

Three dimensional Digital Image Correlation (3D-DIC) is used in the present study in combination with traditional clip gauges to assess the efficiency of osteosynthesis techniques widely applied to fixate acetabular fractures. Thirty-five cadaveric semi-pelvises were artificially fractured and fixated with the aid of various combinations of either simple or locking fixation plates and screws. The fractures simulate a variation of the acetabular fractures known as “T-type”. The fixated constructs were properly supported to simulate single-leg stance. Quasi-static loading under displacement-control mode was monotonically imposed until one out of two predefined failure criteria (related either to the load attained or the displacement induced) was satisfied. It was proved that 3D-DIC, besides its advantages related to the full-field description of the displacement field, is an extremely valuable recording tool for the needs of the present protocol since it permits post-mortem evaluation of the relative displacement and relative sliding of the fixated parts, relieved from the influence of rigid body displacement and rotation. Proper elaboration of the data provided by the 3D-DIC system, implemented on the basis of an alternative assessing criterion, permitted a “fair” comparison between the fixation techniques, in terms of the response of all three independent fractures forming the specific variation of the T-type fracture. It was concluded that suitable combination of simple and locking reconstruction plates offers increased stability of the fixated semi-pelvises, compared to the other fixation techniques studied.