BACKGROUND:In closed fractures, the initial hematoma that is inclined to remove is seldom considered as the important reasons for bone healing. OBJECTIVE:To observe the mechanism and potential role of original fracture hematoma in fracture healing. METHODS:Ninety-six patients with closed fractures of the long bones undergoing open reduction and internal fixation were randomly divided into experimental group (n=48) and control group (n=48). In the experimental group, original fracture hematoma, 1.0-2.0 mL, was first taken out during the internal fixation and placed into a special sterile plastic bag; then, 3-4 pieces of hematomas were filed into the fracture site and sutured layer by layer. On the contrary, original fracture hematomas from the control group were discarded. Blood samples were extracted to detect the biochemical indicators at 1 month after internal fixation. X-ray examination was done at 1, 3, 6 months after internal fixation for observation of fracture healing. RESULTS AND CONCLUSION: X-ray films showed that the healing rate at 3 months after operation was 95% in the experimental group and 78% in the control group, and there was a significant difference between the two groups (P < 0.05). Levels of bone glaprotein, I-type precolagen carboxy terminus peptide and serum bone alkaline phosphatase were significantly higher in the experimental group than the control group (P < 0.01 orP < 0.05). These findings indicate that the original fracture hematoma can accelerate calus formation, promote bone induction, provide nutrition to the fracture site, and participate in revascularization. Therefore, the original fracture hematomas is one of the effectively therapeutic methods for union and nonunion of fractures.