Establishment of heterotopic ossification via sharp instrument injury in rats

OBJECTIVE: To establish an animal model for heterotopic ossification (HO) induced by sharp instrument injury in Sprague-Dawley (SD) rat and to investigate its possible mechanism. MATERIALS AND METHODS: A total of 48 male SD rats were divided into 3 groups (n=16). In sham group, incision and suture were performed only in the left leg. Partial tenotomy was performed in the left Achilles tendons in the PAT group. In Achilles’ tenotomy (AT) group, tenotomy was performed in the left Achilles tendons to establish animal model of EO. X-ray and histological examinations were made at 6 and 10 weeks after operation. RESULTS: No HO occurred in the sham and PAT groups. In AT group, X–ray results on 4 rats showed cartilage and bone formation while the remaining 4 rats showed chondrification in histological examination at 6 weeks after operation. At 10 weeks all rats showed bone formation with trabecular bone. This kind of HO usually develops through a process of endochondral ossification. CONCLUSION: Tenotomy is a simple, effective and feasible method to induce HO.