The effect of a silane coupling agent on the bond strength of bone cement and cobalt-chrome alloy

Debonding of the cement-implant interface has been hypothesized to be the l eading initial indicator of failed total hip prostheses. Many attempts have been made to increase the bond strength of this interface by precoating th e implant, increasing the implant's surface roughness, and creating macro-g rooves or channels on the implant. However, each of these approaches introd uces new complications. This study introduces a unique silane coupling agen t used to chemically bond the bone cement to the implant. Cylindrical cobal t-chrome samples were treated with the silane coupling agent, bonded to pol ymethylmethacrylate, and pushed out to failure. The mean shear strengths we re compared to the failure strengths of untreated samples. Half of the spec imens were tested immediately following cement curing, and the other half w ere tested after immersion in saline solution for 60 days. The mean shear s trength of the silane-coated samples ranged from 18.2 to 24.1 MPa, and the mean shear strength of the uncoated samples ranged from 7.6 to 15.0 MPa. Th e increase in strength following silane coating noted in this study may inc rease the longevity of the implant by decreasing debonding at the interface and, therefore, subsequent failure due to loosening. (C) 2000 John Wiley & Sons, Inc.