Adverse reaction to metal bearing leading to femoral stem fractures: a literature review and report of two cases.

Metal-on-metal (MoM) bearing in total hip replacement (THR) has a high failure rate due to adverse reaction to metal debris (ARMD). There is a spectrum of soft tissue and bony changes in ARMD including muscle necrosis and osteolysis. In our institution, more than 1500 MoM THRs were implanted since 2003. Recently, we have revised significant numbers of these. We report our experience and management of a mode of failure of MoM THR that has been infrequently reported-the distal femoral stem fracture. We report on two patients who presented with worsening pain attributable to fracture of the femoral stem. Severe femoral osteolysis led to loss of proximal stem support and eventual fatigue fracture of the component. Both patients were revised employing a posterior approach. Bone trephine was used to extract a well-fixed distal stem fragment without any windows. Both patients had successful outcome after revision with excellent pain relief and no complications.