Fatigue behaviour of porous polysulphone surface coatings for orthopaedic applications

Porous polysulphone (PPSF) has recently been selected as a candidate material for use as a prosthetic surface coating in orthopaedic applications to acommodate ‘bone ingrowth’ for fixation to the skeletal system. The tension-loaded fatigue behaviour of PPSF was characterized based on the interpretation of stress/life ( S/ N) data. Results of this investigation indicate that the fatigue life of PPSF is governed by crack propagation across the sintered necks of the porous structure. In addition, experimental data revealed that the fatigue strength-reduction factor, K f , remains equivalent to the tensile notch strength-reduction factor for a wide range of fatigue lives. However, analytical results indicate that the material has a low notch sensitivity and that a single application of a theoretical elastic stress-concentration factor in a fatigue analysis would be inappropriate.