Design of a controlled-stiffness composite proximal femoral prosthesis

The design and prototype manufacture of a controlled-stiffness composite fe moral prosthesis is described. The prosthesis is composed of a cobalt-chrom e core surrounded by a flexible composite outer layer. By varying the compo site layer thickness it was possible to control the prosthesis stiffness. T he new design was critically assessed by means of finite-element method and its predicted performance compared with those of conventional, single-modu lus prostheses. A simple model based on composite beam theory was used to d etermine the optimum thickness of the composite material. The composite was made of an epoxy resin reinforced with braided hybrid carbon-glass pre-for ms. A prototype incorporating the novel concept design was manufactured by using the compression moulding technique. (C) 2000 Elsevier Science Ltd. Al l rights reserved.