【Abstract】 Objective To establ ish a animal model of osteonecrosis of femoral head in canine l ike human.Methods The thermal field of canine’s femoral head was three-dimensionally analyzed with fluent 6.2 software so that the best cryosurgery patent could be designed to maximize the osteonecrosis and minimize extra surgery trauma with the cryosurgery system invented by Shanghai Jiaotong University. Liquid nitrogen was pressurized to 0.5 MPa, poured into femoral head for 6.5 minutes, rewarming to 2 for 5 minutes and then repoured into it again for another 6.5 minutes. Ten three-foot canines were conducted as the animal models of osteonecrosis of femoral head according to the method above. At the end of followup,the results were reviewed by radiologic and pathologic check. Two dogs were conducted as control group. Results In the experimental group, one of the ten canines was testified to occur osteonecrosis of femoral head after one week pathologically, cell death and vessel breakage of cavitas medullaris in the femoral head was obvious under microscope; in other nine canines beingstill under follow-up, five with three-month follow-up at least progressed to the collapse of femoral head l ike human (Ficat III). In control group, no osteonecrosis was found. Conclusion Cryosurgery for osteonecrosis of the femoral head in three-foot canine model may become a method to establ ish the animal model of osteonecrosis of femoral head l ike human.
Objective To establ ish an animal model of osteonecrosis of the femoral head (ONFH) l ike human. Methods Ten healthy adult three-leg Beagle male dogs weighing (16.0 ± 1.6) kg were conducted as the animal model of ONFH according to the schedule of cryosurgery designed in advance in which l iquid nitrogen, pressurized to 0.5 MPa, was poured into the femoral head for 16.5 minutes. After rewarmed to 0℃ for 10 minutes, the l iquid nitrogen was repoured into the femoral head for another 16.5 minutes. At the end of the follow-up, the results were reviewed by pathologic check. One dog was conducted as control group. Results The first boundary temperature of (—27.9 ± 4.3)℃ was higher than the second boundary temperature (— 31.3 ± 4.7)℃ by —3.4℃ , and there was significant difference (P lt; 0.01). The diameter of the femoral head of (17.7 ± 1.1) mm was l inearly (^ y= — 2.6 － 2.409 x) correlated to boundary temperature by Pearson analysis, and the R rate was —0.977 (Plt; 0.05). Four dogs in experimental group progressed to collapse of the femoral head l ike human in the 6th month after operation. The rate of the femoral head collapse rose to 44.4%. In the control group, osteonecrosis was never found. Conclusion Cryosurgcry for osteonecrosis of the femoral head in the three-leg canine model may become a method to establ ish an animal model of ONFH l ike human.