title: Biocompatibility and functionality of the degradable polymer alkylene bis(dilactoyl)-methacrylate for screw augmentation in vivo.
abstract: Recently, a new degradable polymer has been developed on the basis of alkylene bis(dilactoyl)-methacrylate as an alternative material for screw augmentation. The polymer has been investigated in vitro and in a short-term experiment in rabbits exhibiting promising results. The aim of the present study was to investigate its long-term biocompatibility and mechanical functionality in a large animal model. The polymer was used for screw augmentation in the cancellous bone of the femoral condyle and tibia epiphysis of 12 sheep and was compared to polymethylmethacrylate (PMMA) augmented and nonaugmented screws. After an implantation period of 6 months, bone, regional lymph nodes, and several organs were histologically evaluated. The mechanical efficacy was investigated by a biomechanical pullout test. A lot of mononuclear macrophages and multinuclear foreign body giant cells with incorporated polymer particles indicate strong inflammatory reactions. Large osteolysis zones with osteoclasts were found in the surrounding polymer. The polymer was fragmented but not substantially degraded. Polymer particles were also found in the regional lymph nodes. Lung, liver, kidney, and spleen did not show any pathological signs. The pullout force of screws augmented with the new polymer was significantly reduced in comparison to PMMA augmented and nonaugmented screws, respectively. It was concluded that the material has poor biocompatibility and cannot be recommended for clinical application as screw augmentation material.
authors: Institute of Orthopaedic Research and Biomechanics, University of Ulm, Helmholtzstrasse 14, 89081 Ulm, Germany. anita.ignatius@medizin.uni-ulm.de
authors: Anita A
authors: AA
authors: Ignatius
authors: Peter
authors: P
authors: Augat
authors: Elke
authors: E
authors: Hollstein
authors: Sandra
authors: S
authors: Schorlemmer
authors: Manfred
authors: M
authors: Peraus
authors: Peter
authors: P
authors: Pokinskyj
authors: Lutz
authors: L
authors: Claes
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D001863:Bone Screws; D005121:Extremities / Q000601:surgery; D005260:Female; D050723:Fractures, Bone / Q000601:surgery; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry*; D023421:Models, Animal; D010014:Osteolysis; D011108:Polymers / Q000737:chemistry*; D012756:Sheep
chemical_list: D001672:Biocompatible Materials; D008689:Methacrylates; D011108:Polymers