The Experimental Study On The Interventional Effect In Steroids-induced Femoral Head Osteonecrosis Of The Intraosseous High Pressure After The Excision Of Obturator Nerve

Objective：1、To observe the living tissue of femoral head and thepathological changes of bone morphology in the effect of hypodermic injectionof prednisolone acetate.2、To investigate the changes of intraosseous pressureand hemorrheology on Steroid-induced avascular necrosis of femoral head（SANFH）3、To investigate the effects of intraosseous pressure andhemorrheology of the obturator nerve amputation on Steroid-induced avascularnecrosis of femoral head（SANFH）.Methods：40healthy mature Chinese whiterabbits，were selected randomly divided into three groups：9as the control group，15as the model group and16as the intervention group.The rabbits weredisposed by subcutaneous saline injection（0.32ml/kg）weekly. The rabbit modelof early femoral head necrosis was constructed with the modified method ofsubcutaneous prednisolone acetate injection （8mg/kg）weekly.The obturatornerve of intervention group was excised after4weeks.A total of three timepoints were selected after subcutaneous prednisolone acetate injection, includingpre-experiment，4weeks(preoperative) and8weeks. The intraosseous pressureand local tissue hemorrheology of the aminals Femoral head were measured ineach group and at three time points.Then，three animals randomly selected andsacrificed, the femoral heads were examined by gross observation， thepresence of histopathological HE staining and transmission electronmicroscope.Results：1、The histopathological observation showed that thetrabecular bone became sparse, thin and discontinuous. That also showed thatthe amount of hematopoietic cell was decreased,and the corpulent adipose cellincreased in the medullary canal where the areas of coagulative necrosis are seenand empty lacunae increased；Compared with the model group，the degree ofintraosseous pressure and bone necrosis of intervention group were reduced.Lacunae rate of4and8weeks（25.56±2.60）%and（36.44±2.79）%respectively,were higher than the control group（11.64±3.19）%and（12.13±1.72）%, and thedifferece between two groups and two time points in model group wasstaistically significant (P <0.05).2、Compared with the control group, theintraosseous pressure and blood viscosity of femoral head of model group wassignificantly increased at two time points. Compared with the model group inweek four, the intraosseous pressure and blood viscosity of femoral head ofmodel group was significantly increased in week eight. The differece betweentwo groups and two time points was staistically significant (P <0.05),and the difference between two points in the model group was staistically significant(P <0.05).3、Compared with the control group,the intraosseous pressure，thehemorheology and bone lacuna rate of the aminals femoral head of the rest twogroups were significantly increased after4,8weeks(P<0.05)；Compared with themodel group，three indicators were decreased and the difference between twogroups was staistically significant(P<0.05).Conclusion：1、 large dose ofhormone may cause avascular necrosis of femoral head in rabbits. With theincreasement of hormone dosage, the degree of bone necrosis was aggravated.2、With the increasement of hormone dosage, the intraosseous pressure andblood viscosity of femoral head was aggrandized, which is one of importantpathogenesis of ischemic necrosis of femoral head.3、 Obturator nerveamputation can reduce intraosseous pressure and values of hemorrheology ofSANFH，so as to effectively delay or reduce the incidence offemoral headnecrosis...