An Experiment Studies On Osteonecrosis Of The Femoral Head Of Adult Rabbits Treated With Extrocorporeal Shock Wave Therapy

Objective: To investigate and contrast the effect of physical damage and hormonal of rabbits' femoral head necrosis. To Study the therapeutic mechanism of medication and to look for a safe and reliable method for clinical treatment.Methods: Twenty-two Japanese rabbits were used for establishing the model of femoral head necrosis .The animals were divided into two group at random, freezing group (11)which were operated and used liquid nitrogen to freezing the femoral head. Hormonal group(11) which were injected horse serum 5mg kg-1twice and Methylpredisolone 40 mg kg-1 three times .The left back legs of all rabbits did not treated as control group, the right back legs were treaded with extrocorporeal shock wave(ESW). X-ray, pathological examination and electron microscope examination were adopted to observe the changes of the femoral head in different periods(after therapy 2 , 4, 8weeks).Results: After extrocorporeal shock wave treated, the size of femoral head necrosis area doesn't show a significant difference between the right and left legs by X-ray picture in the frozen group at the 2th and 4th week. However, the difference is obviously observed in the X-ray picture at the 8th week, three rabbits' left femoral head collapsed totally and there is few bone remained, the other five rabbits' remained size of the left side femoral head is smaller than half of normal femoral head. But the right femoral head of all animals are collapsed slightly, the size of collapse part is smaller than half of normal femoral head. Similarly, the shape of left femoral heads isn't different from the right femoral heads' at the 2th and 4th week. At the 8th week after extrocorporeal shock wave treated, the size of six rabbits' left side femoral heads is smaller than right side femoral heads, two rabbits' size of left side femoral head haven't difference contrast with the rights'. We count the number of lacuna, empty lacuna, osteoblast and blood vessel in ten view of microscope by 100 times magnification, calculated the statistical date and conclude the treated group' s ratio of empty lacuna is less than the control group' s notably(P<0.001), the number of osteoblast (P<0.01) and blood vessel (P<0.05) are more than the control group notably.Conclusion: Extrocorporeal shock wave is a good method to treat the freezing femoral head necrosis. Its effect isn't obviously to the hormonal femoral head necrosis in 8 weeks. The mechanism may consist in re-passing the blocked vessel by calving the thrombus and promoting osteoblast developing.