ABSTRACT
Over 800,000 total hip replacement (THR) operations are performed each year in the UK. A third of these operations fail due to aseptic loosening of the prosthesis. The revision surgeries are carried out using the `Impaction grafting technique’ introduced in Exeter in 1987. This technique largely depends on the mechanical strength of the impacted bone graft into which the prosthesis is fixed. As the patient mobilises the bone graft must withstand forces of 2.5 to 3.5 times the body weight during normal walking. As the operation is essentially long-term, it is very likely that the patient will engage in light sporting events like jogging and swimming several months after the surgery. The light sporting activities will clearly induce larger forces on the bone graft and are cyclic in nature. In this paper we consider the effects of these cyclic forces on the bone graft-prosthesis system. The stresses and deformations in different regions of the bone graft under these forces will be analysed.
