Tensile bonding strength of the cement-prosthesis interface

Abstract

A widely held belief among orthopedic surgeons is that there is no adhesion between polymethylmethacrylate bone cement and metal. However, a bond does form between the cement and the standard grit-blasted implant finish. Moreover, it has been shown that disruption of this bond or "debonding" of this interface is a major factor in the initiation of failure of some cemented total joint arthroplasties. It is the purpose of this study to determine the tensile pull-off strength of the bone cement-implant surface interface. A 1.27 cm (0.5 in) layer of Simplex-P bone cement was cured between two Co-Cr-Mo pins of 2.22 cm (0.875 in) diameter which had the standard implant finish on the surface that was interfaced with the cement. The specimens were tested in an MTS machine in stroke control with a cross head rate of 1 in per minute. The maximum load to failure was recorded. Bonding of the cement to the surface does occur. The tensile pull-off strength of the bone cement-implant surface interface is approximately 5 MPa. Other studies have shown that maintaining this bond between the stem and cement is important in maintaining the stability of cemented total joint arthroplasties.