title: Compressive mechanical properties and cytocompatibility of bone-compliant, linoleic acid-modified bone cement in a bovine model.
abstract: Adjacent vertebral fractures are a common complication experienced by osteoporosis patients shortly after vertebroplasty. Whether these fractures are due to the bone cement properties, the cement filling characteristics or to the natural course of the disease is still unclear. However, some data suggests that such fractures might occur because of an imbalance in the load distribution due to a mismatch between the elastic modulus (E) of the bone-cement composite, and that of the vertebral cancellous bone. In this study, the properties of bone-compliant linoleic acid-modified bone cements were assessed using a bovine vertebroplasty model. Two groups of specimens (cement-only and bone-cement composites), and four subgroups comprising bone cements with elastic moduli in the range of 870-3500MPa were tested to failure in uniaxial compression. In addition, monomer release as well as time and concentration-dependent cytocompatibility was assessed through the cement extracts using a Saos-2 cell model. Composites augmented with bone-compliant cements exhibited a reduction in E despite their relatively high bone volume fraction (BVF). Moreover, a significant positive correlation between the BVF and the E for the composites augmented with 870MPa modulus cements was found. This was attributed to the increased relative contribution of the bone to the mechanical properties of the composites with a decrease in E of the bone cement. The use of linoleic acid reduced monomer conversion resulting in six times more monomer released after 24h. However, the cytocompatibility of the bone-compliant cements was comparable to that of the unmodified cements after the extracts were diluted four times. This study represents an important step towards introducing viable bone-compliant bone cements into vertebroplasty practice.
authors: Division of Applied Materials Science, Department of Engineering Sciences, The Ångström Laboratory, Uppsala University, Uppsala, Sweden.
authors: Alejandro
authors: A
authors: López
authors: Division of Applied Materials Science, Department of Engineering Sciences, The Ångström Laboratory, Uppsala University, Uppsala, Sweden.
authors: Gemma
authors: G
authors: Mestres
authors: Division of Applied Materials Science, Department of Engineering Sciences, The Ångström Laboratory, Uppsala University, Uppsala, Sweden.
authors: Marjam
authors: M
authors: Karlsson Ott
authors: Division of Applied Materials Science, Department of Engineering Sciences, The Ångström Laboratory, Uppsala University, Uppsala, Sweden.
authors: Håkan
authors: H
authors: Engqvist
authors: Institute for Biomechanics, ETH-Zürich, Zürich, Switzerland.
authors: Stephen J
authors: SJ
authors: Ferguson
authors: Division of Applied Materials Science, Department of Engineering Sciences, The Ångström Laboratory, Uppsala University, Uppsala, Sweden.
authors: Cecilia
authors: C
authors: Persson
authors: Institute for Biomechanics, ETH-Zürich, Zürich, Switzerland. Electronic address: bhelgason@ethz.ch.
authors: Benedikt
authors: B
authors: Helgason
mesh_terms: D000818:Animals; D001843:Bone Cements / Q000009:adverse effects* / Q000737:chemistry*; D002417:Cattle; D045744:Cell Line, Tumor; D019245:Compressive Strength; D019787:Linoleic Acid / Q000737:chemistry*; D008422:Materials Testing; D020366:Methylmethacrylate / Q000737:chemistry; D013977:Tibia; D013997:Time Factors; D054854:Vertebroplasty
chemical_list: D001843:Bone Cements; D020366:Methylmethacrylate; D019787:Linoleic Acid
keywords: Adjacent vertebral fractures; Bone–cement composites; Linoleic acid; Low-modulus bone cement(s); Monomer release; Vertebroplasty