title: A new bioresorbable polymer for screw augmentation in the osteosynthesis of osteoporotic cancellous bone: a biomechanical evaluation.
abstract: The aim of the study was to assess the mechanical efficacy of a new resorbable polymer developed on the basis of alkylene bis(dilactoyl)-methacrylate to improve the anchorage of osteosynthesis material in cancellous bone. Cancellous bone screws were inserted in bovine as well as in human vertebrae and human femoral condyles and were augmented with the new polymer or polymethylmethacrylate (PMMA), respectively. Nonaugmented screws were used as controls. A removal torque test, a dynamic fatigue test, and a pullout test were performed. Augmentation with the new polymer increased the removal torque by 84% in human femoral bone. In the dynamic fatigue test of bovine vertebrae, the removal torque after cyclic loading was 115% higher for the new polymer compared to the nonaugmented controls. In the human vertebrae, the reinforcement with the new polymer increased the removal torque after dynamic loading by 114%. The augmentation with the new polymer increased the pullout force by 88% in bovine vertebrae and by 118% in human vertebrae in comparison to nonaugmented screws. It was concluded that augmentation by the new resorbable polymer significantly enhanced the anchorage of bone screws in cancellous bone. The mechanical efficiency of the new polymer was comparable to that of PMMA cement.
authors.affiliation: Institute of Orthopaedic Research and Biomechanics, University of Ulm, Helmholtzstrasse 14, 89081 Ulm, Germany. anita.ignatius@medizin.uni-ulm.de
authors.forename: A A
authors.initials: AA
authors.lastname: Ignatius
authors.forename: P
authors.initials: P
authors.lastname: Augat
authors.forename: M
authors.initials: M
authors.lastname: Ohnmacht
authors.forename: P
authors.initials: P
authors.lastname: Pokinskyj
authors.forename: H J
authors.initials: HJ
authors.lastname: Kock
authors.forename: L E
authors.initials: LE
authors.lastname: Claes
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D001696:Biomechanical Phenomena; D001843:Bone Cements / Q000737:chemistry; D001863:Bone Screws; D002417:Cattle; D006801:Humans; D066298:In Vitro Techniques; D008422:Materials Testing; D010024:Osteoporosis / Q000601:surgery*; D011108:Polymers / Q000737:chemistry; D019904:Polymethyl Methacrylate
chemical_list: D001672:Biocompatible Materials; D001843:Bone Cements; D011108:Polymers; D019904:Polymethyl Methacrylate