Hydroxylapatite/poly(L-lactide) composites: an animal study on push-out strengths and interface histology.
In the development of new materials for resorbable systems for bone fixation and replacement, composites of hydroxylapatite and poly (L-lactide) (HA/PLLA) were tested. In a transcortical implantation model in goats the interactions at the bone-implant interface were studied with post-operative intervals up to 1 year. Push-out testing of the implants indicated that PLLA reinforced with 50 wt% hydroxylapatite or PLLA plasma-sprayed with a hydroxylapatite coating of 50 microns thickness increases interfacial shear strength at 3 months of implantation when compared to unfilled poly(L-lactide) (P < .01). Scanning electron microscopy showed that the failure mode was predominantly at the coating-implant interface. Implantation periods longer than 3 months did not result in a significant increase in push-out strength because of the resorbing PLLA matrix. In support of the above findings there was histological evidence, on a light microscopical level, of increased bone contact at the interface for the composites, HA incorporated in or coated on PLLA, compared to unfilled poly(L-lactide).
Department of Biomaterials, School of Medicine, University of Leiden, The Netherlands.
C C
CC
Verheyen
J R
JR
de Wijn
C A
CA
van Blitterswijk
K
K
de Groot
P M
PM
Rozing
D000818:Animals; D001672:Biocompatible Materials; D001842:Bone and Bones / Q000166:cytology* / Q000502:physiology; D017886:Durapatite; D005260:Female; D005269:Femur; D006041:Goats; D006882:Hydroxyapatites; D007773:Lactates; D019344:Lactic Acid; D008855:Microscopy, Electron, Scanning; D011091:Polyesters; D011108:Polymers; D019736:Prostheses and Implants; D013718:Tensile Strength; D013997:Time Factors
D001672:Biocompatible Materials; D006882:Hydroxyapatites; D007773:Lactates; D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C033616:poly(lactide); D017886:Durapatite