[In vivo study of degradation of poly-(D,L-) lactide and poly-(L-lactide-co-glycolide) osteosynthesis material].
OBJECTIVE
Comparison of the degradation of poly(D,L)lactide (Resorb X) or poly(lactide-co-glycolide) (LactoSorb) in vivo.


METHODS
LactoSorb and Resorb X osteosynthesis plates were fixed at the lateral aspect of the femora of 26 Chinchilla rabbits using the respective osteosynthesis screws. After intraperitoneal injection of fluorochromes the screw plate bone blocks were resected after 1, 6, 12, 14, 16, 21, 26 months and radiologic, histologic as well as fluorescence microscopic examinations were carried out.


RESULTS
Newly formed bone was detectable above and beneath the polymers 1 month after the implantation. The implants were totally covered by newly formed bone after 6 months. While the LactoSorb screws were found to be as birefringent as after 1 month, in the Resorb X screws a continuous resorption by phagocytizing marrow cells starting from the periphery was detectable. Resorb X was totally resorbed in histologic slides 12 months after implantation, while total resorption of LactoSorb lasted 14 months; both polymers were replaced by marrow cells. Bone remodeling was not finished 26 months after implantation in both polymers.


CONCLUSIONS
Resorption of Resorb X was finished earlier than the resorption of LactoSorb. Both materials were found by fluorescence microscope to be completely resorbed after 12 or 14 months, but bone remodeling of the screw holes was not yet finished 26 months after implantation.
Heidemann
W
W
Klinik für Mund-, Kiefer- und Gesichtschirurgie, Otto-von-Guericke-Universität Magdeburg. WolfgHeidemann@aol.com
Fischer
J H
JH
Koebke
J
J
Bussmann
C
C
Gerlach
K L
KL
D020341:Absorbable Implants; D000818:Animals; D001673:Biodegradation, Environmental; D001860:Bone Plates; D001863:Bone Screws; D005260:Female; D005269:Femur / Q000473:pathology / Q000601:surgery; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D019344:Lactic Acid / Q000493:pharmacokinetics*; D008422:Materials Testing; D008856:Microscopy, Fluorescence; D016348:Osseointegration / Q000502:physiology; D011091:Polyesters / Q000493:pharmacokinetics*; D011100:Polyglycolic Acid / Q000493:pharmacokinetics*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000493:pharmacokinetics*; D011817:Rabbits
D011091:Polyesters; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; C033616:poly(lactide)