Surface roughness of retrieved CoCrMo alloy femoral components from PCA artificial total knee joints

In this study, we analyzed the surface roughness of retrieved cobalt-chromi um-molybdeuum (CoCrMo) femoral components of porous coated anatomic (PCA) a rtificial total knee joints, using a white light interference surface profi lometer (WLISP), Thirty-eight PCA retrieved specimens obtained from the And erson Clinic (Arlington, VA) were used. The artificial knees were originall y implanted between 1982-1993, and the specimens were retrieved during revi sion surgeries between 1988-1996, We examined specimens damaged by three we ar modes: femoral component against the ultra high molecular weight polyeth ylene (UHMWPE) articular surface (mode I), femoral component against the me tal tibial tray (because of UHMWPE tibial component wear-through) (mode II) , and femoral component against metal-debris-embedded-UHMWPE (with metal de bris from the porous coating) (mode IU), The mean surface roughness of each femoral component was the average of 80 surface roughness measurements. Th e in vivo alloy femoral component surfaces were rougher by an order of magn itude over controls, and the alloy surfaces were predominantly worn by the formation of parallel scratches in the direction of articulation. There was no correlation between the surface roughness of the femoral components and patient age, sex, weight, and total time of implantation. Significant surf ace roughness increases accompanied mode II and mode III wear. Different ca rbide morphologies were found on different femoral component surfaces, indi cating that a variety of sintering processes, with different times and temp eratures, may have been applied to the alloy femoral components during manu facture. Metal component roughness may be important to the wear of UHMWPE c omponents and the success of total artificial knee joint, (C) 2000 John Wil ey & Sons, Inc.