The Experimental Study On Effect Of Reaming On Intramedullary Osteogenesis In Long Bone In Rabbits

ObjectiveTo promote fracture healing and reduce complication is the hot problem of research in orthopedics surgery .This experiment was to explain the effect of reaming on intramedullary osteogenesis in long bone, and to explore re-injury in fracture management.Methods1.Thirty New Zealand rabbits, aged from 3 to 5 months, weighing from 2.5kg to 3.0kg were used for the study. After bilateral radial defect of 3mm long was made, the periosteum of 10mm long near the fracture defect was removed .Forty anterior limbs were divided into two groups. In experimental group ,reaming was made with a drill of 1.0-1.5mm diameter, The control group was an unreaming one. By the end of 2nd,4th and 8th,anatomic observation, X-ray, bone mineral density(BMD),and histological examinations were made.Result1.X-ray imaging findings included less callus formation and clear fracture line in the experimental side, but more callus in the control side were found by the end of the 2nd week. Blurring fracture line remaining in the experimental side and disappearance of fracture line and bone union in the control side were found at the end of the 4th week .Bone defect and blocked bone marrow cavity in the experimental side and re-open of bone marrow cavity in the control side were found by the end of the 8th week. These X-ray assessments indicated bone formation in the experimental side were later than that in the control side (p<0.01).2.Histological findings included granulation tissue which was not completely replaced by fibrous tissue,spanocartilage between fragments of the fracture in the experimental side and active proliferation of osteoblast , fibrous connection, cartilage and newly formed bone trabeculae between fragments of the fracture in the control side by the end of the 2nd week; a lot of cartilage tissue increased woven bone in the experimental side and increased osteoblast, and connection of fractures in the control side by the end of the 4th week; woven bone between fragments of the fracture and defect in the experimental side and excellent remodeling of callus with lamellar bone,rechanellization of bone marrow cavity in the control side by the end of the 8th week.3.The bone mineral density (BMD) findings included lower- BMD in the experimental side than that in the control side by the end of the 2nd 4th and 8th week and significant difference between both sides (p<0.05).ConclusionsInternal callus formation was decreased intramedullary osteogenesis after reaming, the re-injury in fracture treatment should be emphasized.