Biological evaluation of carbon-fibre-reinforced polybutyleneterephthalate (CFRPBT) employed in a novel acetabular cup

Polymer composites are potentially useful materials for orthopaedic applications as they can be tailored to closely match the various moduli of bone. The Cambridge epiphyseal cup has been designed using one such material, carbon-fibre-reinforced polybutyleneterephthalate (CFRPBT), so that more of the load can be transferred to bone in order to reduce bone loss around the implant. We have evaluated the suitability of CFRPBT for this application using several standard and custom biological tests, both in vitro and in vivo, and have also started the initial clinical evaluation of the prosthesis. CFRPBT showed no toxicity in bulk form and only minimal toxicity as a particulate. It was non-haemolytic, non-immunogenic and showed no genotoxicity. No adverse responses were seen after in vivo implantation, and the results obtained following 9 months of clinical evaluation have been very encouraging with a good clinical outcome and good bone bonding to the hydroxyapatite-coated CFRPBT.