title: The long-term behavior of poly-L-lactide screws in a minipig fracture model: preliminary report.
abstract: The long-term degradation tissue response to poly-L-lactide (PLLA) screw was investigated for a minipig tibia fracture. As a bone-fracture model, three PLLA screws per animal were used to fix a tibia that had been subjected to a crank-shaped osteotomy. A total of 12 nine-month-old male minipigs were used. In time period from 1 month to 3 years, clinical, radiographic, and pathological studies were conducted. On macroscopic examination, no clear granuloma or fistula formation was noted for 3 years. On microscopic examination, no osteoclasts or giant cells were detected around the screws during the 3 years postoperatively. A substantial degradation of PLLA screw was observed between 2 and 3 years. At 3 years only slight residual breakdown products were found in macrophages. On electric microscopic examination, numerous degraded polymers were seen in a small number of macrophages around the screws. In this model, fixation of tibia fractures using PLLA screws was not associated with any side effects, and was safe and useful for up to 3 years.
authors.affiliation: Department of Orthopaedic Surgery, Nagoya University School of Medicine, Nagoya, Japan. hassey@med.nagoya-u.ac.jp
authors.forename: Yukiharu
authors.initials: Y
authors.lastname: Hasegawa
authors.forename: Shinji
authors.initials: S
authors.lastname: Sakano
authors.forename: Toshiki
authors.initials: T
authors.lastname: Iwase
authors.forename: Hideki
authors.initials: H
authors.lastname: Warashina
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D001673:Biodegradation, Environmental; D001863:Bone Screws; D005593:Fracture Fixation, Internal; D017102:Fracture Healing; D008264:Macrophages / Q000473:pathology; D008297:Male; D008422:Materials Testing; D008854:Microscopy, Electron; D011091:Polyesters; D011859:Radiography; D012449:Safety; D013552:Swine; D013556:Swine, Miniature; D013978:Tibial Fractures / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D013997:Time Factors
chemical_list: D001672:Biocompatible Materials; D011091:Polyesters; C033616:poly(lactide)