title: Mechanical strength of the cement-bone interface is greater in shear than in tension.
abstract: The objective of this study was to determine the relative mechanical properties of the cement-bone interface due to tensile or shear loading. Mechanical tests were performed on cement-bone specimens in tensile (n = 51) or shear (n = 55) test jigs under the displacement control at 1 mm/min until complete failure. Before testing, the quantity of bone interdigitated with the cement was determined and served as a covariate in the study. The apparent strength of the cement-bone interface was significantly higher (p < 0.0001) for the interface when loaded in shear (2.25 MPa) when compared to tensile loading (1.35 MPa). Significantly higher energies to failure (p < 0.0001) and displacement before failure (p < 0.01) were also determined for the shear specimens. The post-yield softening response was not different for the two test directions. The data obtained herein suggests that cement-bone interfaces with equal amounts of tensile and shear stress would be more likely to fail under tensile loading.
authors.affiliation: Department of Orthopaedic Surgery, SUNY Health Science Center at Syracuse, 13210, USA.
authors.forename: K A
authors.initials: KA
authors.lastname: Mann
authors.forename: F W
authors.initials: FW
authors.lastname: Werner
authors.forename: D C
authors.initials: DC
authors.lastname: Ayers
mesh_terms: D000328:Adult; D000368:Aged; D001178:Arthroplasty; D001843:Bone Cements; D001842:Bone and Bones / Q000502:physiology*; D002102:Cadaver; D002484:Cementation; D005269:Femur; D006801:Humans; D008875:Middle Aged; D019904:Polymethyl Methacrylate; D013314:Stress, Mechanical; D013718:Tensile Strength; D016474:Weight-Bearing
chemical_list: D001843:Bone Cements; D019904:Polymethyl Methacrylate