Studies On The Effect Of The Canine Intramedullary Nail Fixation To The Healing Of Fractured Femur

In order to discuss the impact of the osteoblast and the osteoclast on the healing of the bone fracture throughout the process of the healing of the intramedullary nail fixation of the fractured femur; the impact of the NO on the postoperative early inflammation; the correlation between the change of the apoptosis and the change of x-ray graph or the number of the OB and the OC, the model of the surgery on the internal fixation of the fractured femur by using canine bone nail was established. The trial discussed the impact of the fractured femur healing on the internal fixed by using canine bone nail on the level of the entirety, tissue and cell. Feasible data which base on the prediction of the suitable time of the bone nail unloading and improvement of the postoperative care was provided.In the trial 20 canines of the age 6～7 months, weight 5～6 kg were selected. The group dividing of the animals is entirely random according to the every phase point. The random femur of each canine was selected to establish the model of the fracture of femur. The bone callus and the radiography were taken in 5 phase points, so are there 5 groups, and 4 canines in each group. The blood was gotten in 6 phase points, so are there 20 canines in each phase point. It is observed dynamicly that the x-ray graph, the change of the concentration of NO in serum preoperatively and postoperatively, the HE staining situation of the OB and the OC, the apoptosis rate of the bone fracture end.The result of the detection indicated: (1) In the postoperative 5 phase points, the fracture line in the fracture end nearly disappeared in the 75 days after operation, the density of the medullar cavity declined, there were incrassate cortical plate which glazing but not homogenous on the two sides of the femur belonged to calcifying new bone, the bone trabecula gradually transformed into compacted lined up, ripe definitive callus; the fracture line in the fracture end completely disappeared in the 100 days after operation, the medullar cavity almost communicated, exterior and interior callus was becoming more continuous, homogeneous and smooth, bony callus molding basically completed. (2) The change result of the NO content preoperatively and postoperatively indicated: the concentration of the NO in the early period of bone fracture decreased from the 1^st day after the operation. The concentration of NO began to increase obviously from the 3^rd day after the operation, and the concentration reached the highest until the 7^th day, the concentration of NO recovered to the normal level until the 10^th day after the operation. (3) The result of the observation of the HE staining of the OB and the OC: the early and mid period after the operation, the number of the OB was the most, skeleton formation was the most form of the union of fracture; in the last period, there ware mainly OC, bone absorption is the most form of the union of fracture; the blood transportation well improved 100 days after the operation. (4) The apoptosis happened throughout the union of fracture process, especially the 15^th day and the 30^th day after the operation when the average rate of the apoptosis reached the highest.The result of the general trial indicated: the fracture end of the 5⁶-month-age canines healed firmly 70¹00 days when it was suitable to unload the bone nail after the operation. The concentration of NO reached the highest value 3⁷ days after the operation, and recovered to the normal level after 10 days. In order to prevent secondary infection, it was needed antibiosis and anti-inflammatory within the 10 days after the operation. However, the bone nail had great effect to the blood transportation, so the damage to the medullar cavity and surrounded tissue must be reduced as far as possible through the process of the operation; Intramedullary nailing only could not fix firmly with the complicated fracture, so other adjunctive methods were needed to fixation.