An experimental study in rats was accomplished to evaluate the effect of anticoagulant on fracture union, according to clinical, anatomopathological, and biomechanical approaches. Manually, after bone perforation, fracture was produced in the diaphysis of the right tibia, and maintained without immobilization in 72 male rats of Wistar lineage, each 60 days in age with a medium weight of 242 grams. Twelve hours after the fracture, anticoagulant treatment was initiated, and maintained for 28 days. One group received subcutaneous heparin-sodium in a dose of 200 UI/kg every 12 hours, while another group received enoxaparin in a dose of 1mg/kg every 12 hours, doses preconized for treatment of thromboembolism in humans. The third group, the control, received distilled water. During the experiment, the animals were clinically evaluated and after 28 days, sacrificed. In the animals of the three groups, the clinical evolution was similar. By means of anatomopathological analysis made by descriptive and quantitative study, the presence of fibrosis, cartilage, and bone was homogeneous among in the three groups, always with a prevalence of osseous tissue. The biomechanical study, accomplished through a flexion test, demonstrated a stiffness rate and maximum load similar in the three groups. No clinical, anatomopathological, or biomechanical differences were found, resulting in consolidation of all the fractures in agreement with the adopted approaches, concluding that the heparin-sodium and the enoxaparin in these doses, method, and time of administration used did not interfere with the consolidation of tibia fracture in the rat.
Tibia fractures; Wound healing; Rats, Inbred strains; Heparin; Low molecular weight heparin; Biomechanics; Histology
