Long-term in vivo degradation and bone reaction to various polylactides : 1. One-year results

• Published in: Biomaterials Vol. 18; no. 3; pp. 257 - 266
• Main Authors: Mainil-Varlet, P., Rahn, B., Gogolewski, S.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.02.1997; Elsevier Science
• Subjects: Animals; Biodegradation, Environmental; Biological and medical sciences; Bone Nails; bone reaction; Bone Substitutes - chemistry; Bone Substitutes - pharmacokinetics; Bone Substitutes - pharmacology; Calorimetry, Differential Scanning; crystallinity; degradation; Female; implants; Medical sciences; molecular weight; Orthopedic surgery; Polyesters - chemistry; Polyesters - pharmacokinetics; Polyesters - pharmacology; Polylactides; Radiography; Sheep; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Thermodynamics; Tibia - cytology; Tibia - diagnostic imaging; Tibia - drug effects; Time Factors; Tomography, Emission-Computed; Viscosity; degradation; molecular weight; crystallinity; bone reaction; Polylactides; implants; Prosthesis; Molecular weight; Degradation; Osteoarticular system; Tibia; Surgery; Biocompatibility; Biomaterial; Interface reaction; Ungulata; Radiodiagnosis; Resorption; Crystallinity; Experimental study; In vivo; Implanted material; Vertebrata; Lactic acid polymer; Mammalia; Animal; Injection molding; Medical imagery; Sheep; Computerized axial tomography; Artiodactyla
• ISSN: 0142-9612; 1878-5905
• DOI: 10.1016/S0142-9612(96)00126-3

Injection-moulded pins from poly( l-lactide), poly( l/dl-lactide) (95/5%) were implanted in the cortex of the tibiae of sheep. The bone-implant interface was evaluated to observe whether there is any bone resorption caused by the implants. The molecular weight and crystallinity changes upon implantation were also measured. There was no net bone loss around the implants or sterile cyst formation in any of the animals implanted with polylactides up to 1 year. The new bone formed around the poly( l-lactide) and poly( l/d-lactide) pins was separated from the implants with a thin layer of connective tissue. For the implants from poly( l/dl-lactide), there was direct apposition of bone on the polymeric material. At 1 year of implantation, the implants were not completely resorbed, although the molecular weight of polylactides was reduced from 40000–50000 to 500–3000. The crystallinity at 1 year was about 45% for poly( l/d-lactide) and poly( l/dl-lactide) and 65% for poly( l-lactide), respectively, indicating the presence in the degraded material of thermodynamically stable crystals.