Abstract: Objective To compare the effects of non-steroidal anti-inflammatory drugs (NSAIDs) and free radical scavengers (FRS) on formation of traumatic heterotopic ossification (HO) in rabbits. Methods 48 New Zealand rabbits were randomly divided into control group (n=12), NSAIDs group (n=12), FRS group (n=12) and combination group (n=12). The model of traumatic HO was established, and the NSAIDs group, FRS group and combination group were administered indometacin intragastrically, edaravone intravenously and both, respectively, while the control group was administered normal saline for 4 weeks. The incidence and severity of HO were observed with X-ray 8 and 12 weeks after modeling. Results 8 and 12 weeks after operation, the incidence of HO was 33.3% and 41.7% in the NSAIDs group, 43.0% and 45.8% in the FRS group, 29.2% and 37.5% in the combination group, and 70.8% and 75.0% in the control group, respectively. The incidence and severity of HO in all the treatment groups were significantly less than those in the control group (P<0.05), and there was no significant difference among the treatment groups (P>0.05). Conclusion The systemic application of FRS may prevent the formation of HO effectively, similar with the NSAIDs. There is no synergistic effect between them.

Key words: traumatic heterotopic ossification, free radical scavenger, prevention, rabbits