title: Viscoelastic modelling of impacted morsellised bone accurately describes unloading behaviour: an experimental study of stiffness moduli and recoil properties.
abstract: Morsellised bone impaction grafting is commonly used for revision arthroplasty surgery. Several reports have described the mechanical behaviour of this bone material during impaction and loading. In this study we observed the unloading progress. The loose morsellised bone was modified by particle size, particle size distribution, water and fat content. Bone pellets were constructed using different impaction energies. After impaction, the pellets were loaded statically, after which their swelling was recorded at three unloading levels. We deduced two time-dependent recoil properties, the time resistant number (TRN) and the half total swelling time (HTST), and also one stiffness property, the unloading confined modulus of elasticity (UCME). In impacted morsellised bone, the progress of swelling is visco-elastic. Bone pellets with an even distribution of particle sizes have the most rapid recoil. Those with a high liquid content recoil more slowly, and to a significantly greater extent, than pellets with low liquid content. The recoil of pellets with low liquid content is instantaneous, i.e. unrecordable, and the displacement is significantly less than in other pellet samples.
authors.affiliation: Norwegian Orthopaedic Implant Research Unit, NKSOI-MTFS, Olav Kyrresgate 3, 7489 Trondheim, Norway. lfosse@ntnu.no
authors.forename: Lars
authors.initials: L
authors.lastname: Fosse
authors.forename: Sébastien
authors.initials: S
authors.lastname: Muller
authors.forename: Helge
authors.initials: H
authors.lastname: Rønningen
authors.forename: Fridtjov
authors.initials: F
authors.lastname: Irgens
authors.forename: Pål
authors.initials: P
authors.lastname: Benum
mesh_terms: D000818:Animals; D015519:Bone Density / Q000502:physiology*; D001857:Bone Matrix / Q000502:physiology*; D018786:Bone Substitutes; D016025:Bone Transplantation; D002417:Cattle; D004548:Elasticity; D008954:Models, Biological; D013314:Stress, Mechanical; D013718:Tensile Strength; D014783:Viscosity; D016474:Weight-Bearing / Q000502:physiology
chemical_list: D018786:Bone Substitutes