Effect of metal surface topography on mechanical bonding at simulated total hip stem-cement interfaces.
Bonding and loosening mechanisms between bone cement and joint prostheses have not been well identified. In this study, the effects of simulated hip stem surface topography on the interfacial shear strength were examined. Six different surface topographies were used. They were described by several surface characterization parameters that may directly relate to the interfacial bonding strength: average surface roughness R(a), root mean square slope R(Deltaq), correlation length beta, and fluid retention index R(ri). The shear strengths between Palacos E bone cement and stainless steel rods were measured using an Instron materials testing machine. We found that cement can "flow" into the surface microtopography and establish good contact with the metal surface. The results show that the interfacial strength increases monotonically with the increase of R(Deltaq) instead of with R(a). The relationship between interfacial strength and surface parameters shows that a metal stem with an isotropic surface texture, higher R(Deltaq), and greater R(ri) gives a higher interfacial strength.
Research Concentration in Tribology, School of Mechanical, Manufacturing, & Medical Engineering, Queensland University of Technology, GPO Box 2434, Brisbane, Australia.
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D001672:Biocompatible Materials; D001696:Biomechanical Phenomena; D001843:Bone Cements; D006622:Hip Prosthesis; D006801:Humans; D008422:Materials Testing; D008670:Metals; D008954:Models, Biological; D011475:Prosthesis Failure; D013314:Stress, Mechanical; D013499:Surface Properties
D001672:Biocompatible Materials; D001843:Bone Cements; D008670:Metals