Influence of Cement Technique on the Interface Strength of Femoral Components

The optimal surface finish for polymethylmethacrylate cemented femoral components remains controversial. Concerns about early debonding of the prosthesis-cement interface have led surgeons to use roughened surfaces to enhance the cement-prosthesis bond. However, loosening of roughened stems is associated with the generation of excessive wear debris. The purpose of the current study was to determine whether the time to cementation influenced the cement-prosthesis bond of four roughened cobalt chrome surfaces (60 grit-blasted, 10 grit-blasted, 10 grit-blasted with polymethylmethacrylate precoating, glass bead-blasted) and one polished cobalt chrome surface. Fixation strength was assessed using mechanical pushout and tensile testing. Roughened and polymethylmethacrylate precoated surfaces had significantly greater tensile and shear strengths at early cementation times compared with polished surfaces. However, roughened components had significant decreases in tensile and shear strengths as cementation time increased from 2 to 4 minutes and 2 to 6 minutes. In contrast, tensile and shear strengths for the polished surface were significantly lower than for the roughened surfaces and did not change with longer cementation times. When using a roughened or precoated cemented femoral component, the surgeon should consider cementing earlier with wetter cement to maximize the cement-prosthesis bond. When implanting a polished femoral component, it is preferable that the cement is doughy, because the cement-prosthesis bond is not influenced by the wetness of the cement and it is easier to maintain the orientation of the femoral component.