Relative influence of composition and viscosity of acrylic bone cement on its apparent fracture toughness

Article type: Research Article

Authors: Lewis, Gladius

Affiliations: Department of Mechanical Engineering, The University of Memphis, Campus Box 526576, Memphis, TN 38152, USA

Abstract: The composition and viscosity of an acrylic bone cement have both been identified in the literature as being parameters that affect the mechanical properties of the material and, by extension, the in vivo longevity of cemented arthroplasties. The objective of the present study was to determine the relative influence of these parameters on a key cement mechanical property; namely, its fracture toughness. Two sets of cements were selected purposefully to allow the study objective to be achieved. Thus, one set comprised two cements with very similar compositions but very different viscosities (Cemex^{\mathrm{TM}} RX, a medium‐viscosity brand, and Cemex Isoplastic, a high‐viscosity brand) while the other set comprised two cements with similar viscosities but with many differences in composition (Cemex Isoplastic and CMW® 1). Values of the fracture toughness (as determined using chevron‐notched short rod specimens) [K_{\mathrm{ISR}}] obtained for Cemex RX and Cemex Isoplastic were 1.83 ± 0.12 and 1.85 ± 0.12 MPa\surdm, respectively, with the difference not being statistically significant. The K_{\mathrm{ISR}} values obtained for Cemex Isoplastic and CMW^{\mathrm{TM}}1 were 1.85 ± 0.12 and 1.64 ± 0.18 MPa\surdm, respectively, with the difference being statistically significant. Thus, the influence of cement composition on its K_{\mathrm{ISR}} is more marked relative to the influence of cement viscosity. Explanations of this finding are offered, together with comments on the implications of the results for the in vivo longevity of cemented arthroplasties.

Keywords: Acrylic bone cement, fracture toughness, cement composition, cement viscosity

Journal: Bio-Medical Materials and Engineering, vol. 10, no. 1, pp. 1-11, 2000