EFFECTS OF INDOMETHACIN ON BIOLOGIC FIXATION OF POROUS-COATED TITANIUM IMPLANTS

The effect of perioperative administration of indomethacin on attachme nt strength and bone growth into porous-coated titanium implants was e valuated in the canine transcortical plug model. Various drug administ ration protocols simulating clinical use of indomethacin were studied. These included chronic treatment (starting 2 weeks prior to surgery), treatment immediately after surgery, and treatment 3, 6, 9, and 18 we eks following surgery. Indomethacin therapy was continued until sacrif ice at 3, 6, 12, 18, or 24 postoperative weeks. Push-out testing was p erformed to determine the maximum bone-implant interface shear strengt h, and quantitative histologic analysis was used to determine percenta ge of bone ingrowth. When indomethacin was administered chronically or immediately after surgery, a statistically significant decrease in bo ne-implant interface attachment strength was seen at 3 postoperative w eeks but not at later periods. No adverse effect was observed in any g roup after the 3-week period. Quantitative histologic analysis demonst rated no significant differences in percentage bone ingrowth among any of the treatment protocols at 3 or 6 weeks after surgery. No signific ant difference was observed between any of the groups at 18 or 24 week s. The results of this study suggest that perioperative administration of indomethacin does not significantly affect attachment strength or bone ingrowth into porous-coated implants except at early periods, in which cases a transient decrease in attachment strength occurs.