Topography of Live Cartilage by Interferometry and Use of a Tribobioreactor to Assess the Articulation of Cartilage against Various Materials

Advanced cartilage repair techniques and the development of superior resurfacing materials for articulation against cartilage could have a major impact on future treatment and surgical techniques by challenging the current dominance of total hip and knee joint replacements. Such advances require the development of ex vivo cartilage tribological tests that include the capability of monitoring the surface topography of live cartilage. Toward this end, we report on a non-contact, non-destructive technique based on scanning white light interferometry that is capable of measuring the surface topography of viable cartilage. A key aspect of the technique was the development of an optimal surface preparation process. The technique was successfully validated against standard 2-D profilometry. The intrinsic variability of the technique is much less than the average point-to-point variability observed across a cartilage specimen. The technique was thus sufficiently sensitive to readily detect differences in roughness between surfaces of healthy cartilage in different locations on the bovine knee. We also report on the use of a tribobioreactor to assess the articulation of cartilage against various materials with respect to friction, chondrocyte viability, and various biochemical responses. Materials examined included wrought cobalt-chrome-molybdenum alloy, alumina, and ultrahigh molecular weight polyethylene.