(ii) Diagnostic plain film radiology of the failing hip replacement

Conventional radiographs are the main imaging tool for investigating the failing total hip replacement (THR). THRs most commonly fail because of aseptic loosening. The aetiology of aseptic loosening lies in a number of mechanical and biological processes which can result in a variety of different radiological features. These may be used to support or confirm a diagnosis of a loose or failing THR. The reliability and accuracy of some, but not all, of these radiographic signs have been evaluated in the scientific literature. This paper reviews and illustrates these radiographic signs. The pathophysiology for each sign is explained and the evidence supporting the accuracy and reliability is discussed.