title: Biodegradable internal fixation plates enabled with X-ray visibility by a radiopaque layer of β-tricalcium phosphate and poly (lactic-co-glycolic acid).
abstract: Biodegradable polymer plates can be clinically used as an alternative to metal plates (e.g., titanium) for internal fixation, which, however, are not visible with X-ray imaging, often used for post-operative diagnostics. In this study, therefore, we prepared a biodegradable plate enabled with X-ray visibility by attaching a radiopaque layer on a biodegradable fixation plate in clinical use (Inion, Finland). A radiopaque layer was made of a fine powder of a radiopaque agent, β-tricalcium phosphate (TCP) and a biodegradable binder material, poly (lactic-co-glycolic acid) (PLGA), which were physically mixed without change in their chemical structure. The radiopacity increased as we increased the layer thicknesses from 0.5 mm to 1.3 mm. Regardless of layer thickness, however, the radiopacity decreased with time both in vitro and in vivo due to decreasing density of TCP in the layer by swelling and degradation of a binder material, PLGA. The in vivo study with rabbits revealed that a discernible image of the radiopaque plate could be obtained by X-ray for up to 21 days, also showing the overall biocompatibility 6 months after implantation. Therefore, we conclude that the radiopaque plate prepared in this work is a promising fixation device enabled with both X-ray visibility and biodegradability.
authors.affiliation: Department of Materials Science and Engineering, College of Engineering, Seoul National University, Seoul, Republic of Korea.
authors.forename: Catherine
authors.initials: C
authors.lastname: Shasteen
authors.forename: Keun Yung
authors.initials: KY
authors.lastname: Park
authors.forename: Seok Min
authors.initials: SM
authors.lastname: Kwong
authors.forename: Sun Young
authors.initials: SY
authors.lastname: Jung
authors.forename: Seung Ho
authors.initials: SH
authors.lastname: Lee
authors.forename: Chun Gwon
authors.initials: CG
authors.lastname: Park
authors.forename: Myung Hun
authors.initials: MH
authors.lastname: Kim
authors.forename: Sukwha
authors.initials: S
authors.lastname: Kim
authors.forename: Woo-Chan
authors.initials: WC
authors.lastname: Son
authors.forename: Tae Hyun
authors.initials: TH
authors.lastname: Choi
authors.forename: Young Bin
authors.initials: YB
authors.lastname: Choy
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D001860:Bone Plates; D002130:Calcium Phosphates / Q000737:chemistry; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D003287:Contrast Media / Q000737:chemistry; D005269:Femur / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D006811:Humerus / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D019344:Lactic Acid / Q000737:chemistry; D008297:Male; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D016348:Osseointegration; D011100:Polyglycolic Acid / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011817:Rabbits; D011859:Radiography; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties
chemical_list: D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; D003287:Contrast Media; C485817:beta-tricalcium phosphate; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid