Effect of cement pressure and bone strength on polymethylmethacrylate fixation

Abstract

The effect of the quality of the bone and of the cement pressurization magnitude and duration on the fixation achieved with polymethylmethacrylate (PMMA) bone cement is studied in vitro. Seventy-one cement-bone interface specimens, prepared under various conditions of pressurization of low-viscosity bone cement, are tested in tension. The load at failure and the maximum cement penetration are measured to assess the fixation achieved, and the quality of the bone is assessed by determining the compressive strength of each of the bone specimens. Statistical analysis of the data indicates that the pressure magnitude is the most influential of the factors considered in the cement penetration behavior and in the development of failure load capacity. The duration of the pressure does not appear to be a significant factor. The cement penetration is a decreasing function of the bone strength, reflecting a decrease in the porosity and an increase in the area fraction. Although not directly measured in these tests, these latter bone properties are indirectly measured by the bone compressive strength. The effect of increasing bone strength on the failure load is nonlinear. The development of adequate failure load capacity is the result of a balance between the cement penetration allowed by the porosity of the bone and the inherent strength of the cancellous bone itself. Weak bone, although adequately penetrated by cement, cannot provide strong fixation. Stronger, denser bone limits cement penetration, but pressurization enhances development of failure load capacity through more complete infusion and interlocking of the cement in the available pore space. The strength of the fixation achievable for any bone is limited by the intrinsic strength of the bone.(ABSTRACT TRUNCATED AT 250 WORDS)

Revision strategies for complications and failure of vertebroplasties

“…However, injection of viscous cement with low pressure decreases the penetration of the cement into the microstructure of cancellous bone [4]. Krause et al [16] reported that doughy cement on an unclean surface resulted in a very low interface strength compared to a low-viscosity cement made to penetrate a cleaned bone surface.…”

The influence of initial pressurization and cup introduction time on the depth of cement penetration in an acetabular model

“…Three independent variables, which are under the control of the surgeon, determine the intrusion characteristics of the cement: magnitude of cement pressure, duration of pressure application, and viscosity of acrylic cement (Askew et al 1984). Achievement of an adequate cement pressure and penetration in the acetabulum is particularly difficult, given its appearance and anatomy.…”

“…The strength of fixation of the bone-cement interface depends on the quality of the bone bed, the intrinsic properties of the bone cement, and the depth of penetration of the cement. Increased penetration into the porous bone has been shown experimentally to lead to a stronger interface (Askew et al 1984, Maltry et al 1995.…”

The Influence of a Suction Device on Fixation of a Cemented Cup using RSA

“…The aspirator retractor, designed in 2000 and used in our series, reportedly improved cement penetration into trabecular bone in one study [17]. Cement penetration greater than 2 mm and an ideal penetration of 3 to 5 mm reportedly produces the strongest cement-bone interface [1,18,20]. However, we could not confirm an improvement in cement intrusion in this series.…”