Effect of long-term formalin preservation on bending properties and fracture toughness of bovine compact bone

To precisely determine the mechanical properties of a bone, the effects of the preservation method on its mechanical properties need to be minimized. It seems likely that prolonged exposure to formalin (formaldehyde solution) will have some affect the mechanical properties of bone. This study investigated the effect of the formalin fixation method on the bending properties and fracture toughness of bovine cortical bone after short-term and relatively long-term preservation. To determine the elements and the quantities eluted from bone into formalin solution (the preservation medium), qualitative and quantitative analyses were performed by inductively coupled plasma atomic emission spectroscopy (ICP-AES). Formalin fixation augments the bending stiffness of the cortical bone while diminishing its fracture toughness. As the bending strength diminishes concurrently with removal of Ca2+, this implies that inorganic components of bone contribute to its bending strength.