THE EFFECT OF THE ADDITION OF METHYLENE-BLUE ON THE FATIGUE-STRENGTH OF SIMPLEX-P BONE-CEMENT

To aid in cement removal during revision arthroplasty, it has been proposed to add methylene blue to bone cement to provide contrast between the cement and bone. However, it is essential that the fatigue strength of the cement not be reduced by the addition of the methylene blue. The effect of adding 1 mL of an aqueous 1% solution of methylene blue to one pack of Simplex P prepared in the standard fashion (uncentrifuged) was studied. We also measured the fatigue properties of centrifuged Simplex P with three different methylene blue preparations. We studied adding 1 mL of an aqueous 1% solution of methylene blue, 0.5 g of methylene blue powder, and 0.1 mL of a 10% solution of methylene blue per pack of Simplex P bone cement. Adding 1 mL of a 1% methylene blue solution to 40 g of Simplex P without centrifuging the cement after mixing produced a cement with a mean fatigue life comparable to the uncentrifuged Simplex P without the methylene blue. However, the fatigue data scatter was higher for the uncentrifuged methylene blue preparation. The optimum methylene blue impregnated cement preparation was produced by adding 1 mL of a 1% methylene blue solution to 40 g of Simplex P powder, mixing with chilled monomer, and centrifuging for 60 s. Sterile 1 mL vials of 1% methylene blue solution are available in the operating room. Thus the experienced surgeon can use a cement containing color to facilitate distinguishing cement from bone in cases needing revisions without weakening the cement.