Abstract

Failure analysis conducted on fixation devices retrieved from the in vivo environment is presented. The fixation device system was composed of a plate 135°, a dynamic hip screw (DHS), and four cortical screws of the 316L stainless steel. A detailed analysis of the damaged surface and the fractographic study of the devices failed were performed by using conventional optical, scanning and transmission electron microscopy techniques. On the other hand, chemical composition, hardness, and microstructural features were determined and compared with the standard specifications with the aim of verifying if the material per se is responsible for the produced failures. The results from the microfractographic studies indicated that the predominant morphology is that characteristic of a mechanism of fatigue assisted by corrosion. It has to be pointed out that the combination of different factors as the presence of an osteoporotic bone, patient weight band postoperative activity, the delay in the healing of the fracture and some aspects related to the erroneous indication for the use of the fixation devices have also played an important role in causing the failure.