Late degradation tissue response to poly( l-lactide) bone plates and screws

• Published in: Biomaterials Vol. 16; no. 1; pp. 25 - 31
• Main Authors: Bergsma, J.E., de Bruijn, W.C., Rozema, F.R., Bos, R.R.M., Boering, G.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 1995
• Subjects: Acid Phosphatase - metabolism; Adult; Alkaline Phosphatase - metabolism; biodegradation; Biodegradation, Environmental; Bone Plates - standards; Bone Screws - standards; Collagen - metabolism; Enzyme Activation - drug effects; enzyme activity; Humans; L-Lactate Dehydrogenase - metabolism; Lactates - adverse effects; Lactic Acid; Longitudinal Studies; Lysosomes - enzymology; Microscopy, Electron; Microscopy, Electron, Scanning; Middle Aged; Mitochondria - chemistry; Mitochondria - enzymology; Mitochondria - ultrastructure; Mitochondrial Swelling; Molecular Weight; Phagosomes - ultrastructure; Poly ( l-lactide); Polyesters; Polymers - adverse effects; Reoperation; Substrate Specificity; tissue response; Zygomatic Fractures - surgery; biodegradation; tissue response; Poly ( l-lactide); enzyme activity
• ISSN: 0142-9612; 1878-5905
• DOI: 10.1016/0142-9612(95)91092-D

Patients with fractures of the zygomatic bone were treated with high molecular weight poly( l-lactic) acid (PLLA) bone plates and screws. Three years after implantation four patients returned to our department with a swelling at the site of implantation. At the recall of the remaining patients we found an identical type of swelling after the same implantation period. To investigate the nature of the tissue reaction, eight patients were reoperated for the removal of the swelling. The implantation period of the PLLA material varied from 3.3 to 5.7 years. Microscopic evaluation and molecular weight measurements were performed. The excised material showed remnants of degraded PLLA material surrounded by a dense fibrous capsule. Ultrastructural investigation showed crystal-like PLLA material internalized by various cells. The results of this investigation suggest that the PLLA material slowly degrades into particles with a high crystallinity. The intra- and extracellular degradation rate of these particles is very low. After 5.7 years of implantation, these particles were still not fully resorbed.