title: Evaluation of an accelerated aging medium for acrylic bone cement based on analysis of nanoindentation measurements on laboratory-prepared and retrieved specimens.
abstract: The thrust of the study was a critical evaluation of the efficacy of a medium (30% v/v H(2)O(2), at 60 degrees C) that has been suggested in a literature report as being suitable for simulating the oxidative aging process, seen in vivo, in the acrylic bone cement mantles of total hip and knee joint replacements. For this purpose, quasi-static and dynamic nanoindentation measurements were used to obtain material properties--elastic modulus, E; hardness, H; and the variation of the storage and loss moduli with the frequency of the applied indenting force--of PalacosR acrylic bone cement specimens after various periods of immersion (7, 14, 21, and 28 days) in the aging solution, and of specimens prepared from cement mantles retrieved from cemented total hip joint replacements after various times in vivo (0.92-21 years). Also, best-fit relationships were obtained between E and time in the H(2)O(2) solution (t), H and t, E and in vivo time (T), and H and T. This body of results points to the possibility that the aging solution is effective, although the evidence is not conclusive.
authors.affiliation: Department of Mechanical Engineering, The University of Memphis, Memphis, Tennessee 38152, USA. glewis@memphis.edu
authors.forename: Gladius
authors.initials: G
authors.lastname: Lewis
authors.forename: Jie
authors.initials: J
authors.lastname: Xu
authors.forename: Nicholas
authors.initials: N
authors.lastname: Dunne
authors.forename: Catherine
authors.initials: C
authors.lastname: Daly
authors.forename: John
authors.initials: J
authors.lastname: Orr
mesh_terms: D001696:Biomechanical Phenomena; D001843:Bone Cements / Q000737:chemistry*; D004548:Elasticity; D006622:Hip Prosthesis; D006801:Humans; D006861:Hydrogen Peroxide; D007720:Knee Prosthesis; D008422:Materials Testing; D036103:Nanotechnology; D010084:Oxidation-Reduction; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D012996:Solutions; D013997:Time Factors
chemical_list: D001843:Bone Cements; D012996:Solutions; D019904:Polymethyl Methacrylate; D006861:Hydrogen Peroxide