Colchicine inhibits heterotopic ossification: Experimental study in rabbits

Background: Heterotopic ossification is a common complication of hip surgery and musculoskeletal or brain trauma. Objectives: To confirm by in vivo study that colchicine inhibits osteoblast cell proliferation with marked decrease in tissue mineralization. Methods: Heterotopic ossification was induced in three groups of New Zealand white rabbits (females, 6 months old, weight 3-3.5 kg) by injecting 2 ml bone marrow drawn from the iliac crest into their right thigh muscle. To prevent heterotopic ossification, colchicine (0.25 mg/day) was administered orally for 4 weeks to two groups of adult rabbits: group A (preload group) - 1 week preceding bone marrow injection; group B - on day of injection; and group C - control group. Results: After 4 weeks the rabbits were evaluated by radiographs and ultrasound for evidence of heterotopic ossification. At the end of the study histologic samples were taken from all the thighs. Imaging and histologic studies showed, with statistical significance, almost complete prevention of heterotopic ossification formation in group A (preload) and a marked decrease in group B, when compared with the controls where large new bone had formed at the injection site. These results indicated the inhibitory effects of colchicine on a bone-forming process in soft tissue such as heterotopic ossification. Conclusions: The role of colchicine in preventing heterotopic ossification in other bone-forming conditions, such as hip arthroplasty or pelvic trauma, and after brain trauma, remains to be evaluated in a clinical setting.