In vivo evaluation of the bond strength of adhesive 4-META/MMA-TBB bone cement under weight-bearing conditions

Abstract

In order to minimize the problems associated with implant fixation using acrylic bone cement, we studied a new adhesive bone cement that consists of 4-methacryloyloxyethyl trimellitate anhydryde (4-META) and methylmethacrylate (MMA) as monomers, tri-n-butylborane (TBB) as an initiator, and PMMA powder (4-META/MMA-TBB cement). It shows remarkable adhesive properties to metal and bone in vitro. The purpose of this study was to evaluate the strength of the bond of the cement to both metal and bone in vivo under weight-bearing conditions. Metal prostheses were implanted in the right femora of 12 rabbits using either adhesive 4-META/MMA-TBB cement or the conventional PMMA cement, as the control, for fixation. After 4 and 12 weeks, both femora were excised and the same operations were performed in the left femora in vitro. Eighteen femora were sectioned for the mechanical assessment of the bone-cement and cement-implant interfaces. 4-META/MMA-TBB cement had a significantly higher interfacial shear strength than the conventional PMMA cement: 201 N and 90 N, on average, for the implant-cement interface (p<0.01); and 138 N and 89 N, on average, for the bone-cement interface (p<0.01), at 12 weeks. The present results suggest the efficacy of 4-META/MMA-TBB cement in providing greater fixation of implants to bone and promise a firmer intramedullary fixation than the control conventional PMMA cement.