Using 3D digital image correlation to visualise the progress of failure of human proximal femur

Abstract

An accurate measuring tool is required to measure the full-field displacement of the complex geometry of the human proximal femur when subjected to axial loads. Optical techniques, such as digital image correlation (DIC), have been used extensively in order to measure planar or volumetric displacement. Even though DIC methods are now in frequent use in experimental bone mechanics, this technique has only recently been reported to measure 3D proximal ex-vivo femur displacement fields during loading under axial loads. The innovation of this study is to extend the use of the DIC technique to visualise and track the progress of failure of the proximal femur under limb stance configuration. An experimental protocol has been proposed and validated on eight human cadaveric femurs. The results indicated that failure takes place by shearing in the head–neck region. Furthermore, it was found that this method enables to extract additional information on the fracture profile and its initiation. The obtained information can facilitate the interpretation of the in vitro failure behaviour of human femur under axial loading conditions which will serve the validation of hip models.