RESORBABLE CONTINUOUS-FIBER REINFORCED POLYMERS FOR OSTEOSYNTHESIS

Four institutes from three countries in the European Union have collab orated under the BRITE-EURAM framework programme for the development o f processing technologies for resorbable osteosynthesis devices. The d evices should be continuous-fibre reinforced, and the technology shoul d offer the possibility of orienting the fibres in the main trajectori es. Poly-L-lactide and poly-L-DL-lactides have been synthesized for re inforcement fibres and matrix material, respectively. Melt-spun P-L-LA fibres of a strength of 800 MPa have been embedded in an amorphous P- L-DL-LA 70:30 matrix by compression moulding. Ethyleneoxide sterilized samples have been tested in vitro and in vivo. A satisfying bending m odulus has been reached (6 GPa). Yet with 50% strength retention after ten weeks, fast degradation occurred that could be related to residua l monomers. By this fast degradation 70% resorption after one year cou ld be observed in the non-functional animal studies in rabbits. There was only a mild inflammatory reaction, which confirmed the good biocom patibility of the materials even during the resorption period. Further effort has to concentrate on the reduction of initial monomer content . The great advantage of the processing method to orient fibres in the device will be utilized in prototype samples, e.g. an osteosynthesis plate with fixation holes. (C) 1998 Chapman & Hall.