The “Elliptical” Femoral Prosthesis

Abstract

The elliptical femoral prosthesis was designed for solving the problem of the relationship between the prosthetic head and the anatomical acetabulum and to minimize the incidence of cotyloiditis, i.e. acetabular wear-protrusion and pain. Long -term clinical tests have been performed using the Cathcart prosthesis, which is the most advanced technological design. Its basic feature lies in the ellipticity of the head and its development was based on the anatomy and biomechanics of the hip: the femoral head is, in fact, naturally elliptical. The acetabulum is a “deformable” structure, the fades lunata being a stress contact and bearing area, whereas the trabecular system of a “gothic arch”, the “sourcil” and the ileum cortical laminae serve as a load distribution and carrying structure. Clinical results have shown a very low percentage of “cotyloiditis” (1-3%), thanks to the optimal relationship between the prosthetic head and the antomical acetabulum, which guarantees improved distribution of the lubrication stresses and nourishment of the articular cartilage.