The effect of cement stiffness and tibia tray material on the stresses developed in artificial knee

A wide range of materials may be used in manufacturing tibia trays of artificial knee replacements. The Young's modulus of the prosthesis is a critical design variable, since it largely determines how the load is transferred, via the cement to the bone. The current investigation deals with the effect of Young's modulus of the prosthesis and cement and on the stresses developed in the constituents and surrounding bones of artificial knee. Two practical tibia tray materials of diversified Young's modulus were considered in the present work. These showed that increasing the Young's modulus of the prosthesis resulted in weakening the cement layer, while its effect on other constituents is insignificant. A 50% increase in cement Young's modulus resulted in strengthening both the polyethylene and cement layers. (C) 2007 Published by Elsevier Ltd.