THE DEVELOPMENT OF A PHYSIOLOGICAL HIP-PROSTHESIS - THE INFLUENCE OF DESIGN AND MATERIALS

A wooden femur model was used together with matched cementless experim ental implants to investigate the influence of some design concepts on the stress distributions within the proximal femur model, with emphas is on the longitudinal stresses on the outer bone surface, because the longitudinal stresses are believed to be the most important stresses in view of the laws of bone remodelling. In addition to the integratio n of alternative geometrical design concepts in a hip prosthesis desig n, the effect of using alternative materials upon bone stresses was al so investigated. Stress evaluation was made by a combination of two-di mensional finite element analysis and strain-gauge measurements. The r esults and conclusions drawn from these experiments have led to a prot otype of a so-called ''physiological'' hip prosthesis, in which are in tegrated a properly oriented collar, a hinge between stem and neck par t, and a flexible stem.