The effects of low-intensity pulsed ultrasound on bioabsorbable self-reinforced poly L-lactide screws

The effects of low-intensity pulsed ultrasound on the mechanical and molecular properties of self-reinforced Poly L-lactide (SR-PLLA) screws were studied in vitro. SR-PLLA screws of 4.5mm diameter ere exposed on low-intensity ultrasound for 1, 3, 6, 9 and 12 weeks. After exposure, the bending strength, shear strength, and molecular weight were investigated. There were no differences in the ienvstigated properties between the ultrasound exposure and control groups. We found no evidence that low-intensity ultrasound has any effect on the mechanical or molecular properties of SR-PLLA screws in vitro. The present results suggest that biodegradable SR-PLLA fixation devices are compatible with low-intensity ultrasound in vitro. (C) 2002 Elsevier Science Ltd. All rights reserved.