Effect of the crack position in the cement mantle on the fracture behavior of the total hip prosthesis

The mechanical resistance of the total hip prosthesis (THP) and particularly the adhesion quality between the implant and the bone depend primarily on the nature of the cement used and its mechanical and geometrical characteristics. The fracture behavior of the cement is decisive in the failure of the cemented THP. In this work, an analysis of the different criteria of crack propagation in the cement using the finite element method was carried out on various regions of the cement (proximal, medial and distal) with a distributed load on the femoral head of the THP of a 90 kg average body weight. Three orientations of the initial crack were considered: horizontal, vertical and inclined. The two first move in the proximal part towards the distal part, and the third moves in the distal zone. The results show that a crack started in the distal zone of the cement propagates in mixed mode, whilst the one initiated in the proximal zone in mode I.