title: Biomechanical evaluation of bone screw fixation with a novel bone cement.
abstract: BACKGROUND
  Bone cement augmentation is commonly used to improve the fixation stability of orthopaedic implants in osteoporotic bone. The aim of this study was to evaluate the effect of novel bone cements on the stability of bone screw fixation by biomechanical testing and to compare them with a conventional Simplex(®)P bone cement and requirements of the standards.
  
  
  METHODS
  Basic biomechanical properties were compared with standard tests. Adhesion of bone cements were tested with polished, glass blasted and corundum blasted stainless steel surfaces. Screw pullout testing with/without cement was carried out using a synthetic bone model and cancellous and cortical bone screws.
  
  
  RESULTS
  All the tested bone cements fulfilled the requirements of the standard for biomechanical properties and improved the screw fixation stability. Even a threefold increase in shear and tensile strength was achieved with increasing surface roughness. The augmentation improved the screw pullout force compared to fixation without augmentation, 1.2-5.7 times depending on the cement and the screw type. The good biomechanical properties of novel bone cement for osteoporotic bone were confirmed by experimental testing.
  
  
  CONCLUSIONS
  Medium viscosity of the bone cements allowed easy handling and well-controlled penetration of bone cement into osteoporotic bone. By proper parameters and procedures it is possible to achieve biomechanically stable fixation in osteoporotic bone. Based on this study, novel biostable bone cements are very potential biomaterials to enhance bone screw fixation in osteoporotic bone. Novel bone cement is easy to use without hand mixing using a dual syringe and thus makes it possibility to use it as required during the operation.
authors.affiliation: Department of Applied Physics, University of Eastern Finland, Kuopio Campus, Kuopio, Finland. tiina.juvonen@uef.fi.
authors.forename: Tiina
authors.initials: T
authors.lastname: Juvonen
authors.affiliation: Ozics Oy, Tampere, Finland. jp.nuutinen@ozics.com.
authors.forename: Juha-Pekka
authors.initials: JP
authors.lastname: Nuutinen
authors.affiliation: Department of Applied Physics, University of Eastern Finland, Kuopio Campus, Kuopio, Finland. arto.koistinen@uef.fi.|SIB Labs, University of Eastern Finland, Kuopio Campus, Kuopio, Finland. arto.koistinen@uef.fi.
authors.forename: Arto P
authors.initials: AP
authors.lastname: Koistinen
authors.affiliation: Department of Orthopaedics Traumatology and Handsurgery, Kuopio University Hospital, Kuopio, Finland. heikki.kroger@kuh.fi.
authors.forename: Heikki
authors.initials: H
authors.lastname: Kröger
authors.affiliation: Department of Applied Physics, University of Eastern Finland, Kuopio Campus, Kuopio, Finland. reijo.lappalainen@uef.fi.|SIB Labs, University of Eastern Finland, Kuopio Campus, Kuopio, Finland. reijo.lappalainen@uef.fi.
authors.forename: Reijo
authors.initials: R
authors.lastname: Lappalainen
mesh_terms: D000268:Adhesiveness; D001843:Bone Cements; D001863:Bone Screws; D019245:Compressive Strength; D055119:Elastic Modulus; D008422:Materials Testing; D055595:Mechanical Phenomena; D058866:Osteoporotic Fractures / Q000601:surgery
chemical_list: D001843:Bone Cements