Small Joint Replacement with Elastomers

Abstract: Artificial joints are being designed to replace fingers and wrist in which elastomers provide the flexibility. These artificial joints are intended for patients suffering from rheumatoid arthritis whose natural joints have been destroyed by the disease. For these patients it is not essential to restore the full range of movement; the aim is to enable them to perform the tasks of everyday living. However, when elastomers are used in current joint designs, they frequently fracture. To overcome this problem, silicone elastomers are being subject to tensile, tear, bending and fatigue testing as well as water absorption, DMTA and hardness testing; cycling testing is being used to measure viscoelastic properties and determine the effects of loading frequency. The influence of defects such as notches, environmental conditions such as temperature and humidity and the ageing of these materials in physiological solution are also being investigated together with how these properties vary between different biocompatible silicones.