(5) Why do hip replacements fail?

Most hip replacements will last the rest of the patient’s life, i.e. usually in excess of 10-15 years. However, as life expectancy increases and the procedure is used in younger patients due to its relative success, revision surgery may be required as the artificial joint fails. For those failures which occur 5 or more years after the original surgery then the cause is often wear related with an inappropriate biological reaction to the wear debris being the prime cause. Once the joint has been deemed to be a failure, usually through increased pain and a reduction in the patient’s quality of life, a revision procedure takes places in which a new prosthesis replaces the damaged one. These revision procedures are more complex than the initial (primary) operation and been shown to be less successful, hence the drive to ensure that hip replacement survival is increased and that the replacement itself can deal with the variability in the demands placed on it due to different patient lifestyles, diverse surgical techniques and wide ranging pathologies. As well as this wear process, recent work in metal-on-metal implants has identified corrosion processes as a mechanism by which the hips may fail. These corrosive processes can occur at a variety of interfaces and is not limited to the bearing surface. Hence, if we are to combat failure then corrosion as well as wear will be included in our research to provide a fuller, more holistic approach to reducing the effects of wear.

Posted in: Total Hip Replacement