A New Rabbit Model Of The Femoral Head Necrosis

Background: The treatment of the avascular necrosis of femoral head(AVNFH )is a tough task in the field of orthopedics practice. Femoral head collapse base on the absorption of the necrotic bone, The distance and speed of reparation can influence the absorptive Procedure. No effective therapeutic method exits which can stop or reverse the pathologic procedure ,they definitely ends in the collapse of femoral head and further osteoarthritis of hip which is due to many causes, the relative more important one of it is lack of good animal model.Objective: to establish a new animal model of avascular necrosis of the femoral head . Methods: The 4-week old rabbits were tamed in the custom-maded cages.then, by a special way which called from hanging the frontier body the rabbits had to stand on their hind limbs to feed and walk, when the rabbits became mature the femoral head of the rabbits were frozen by liquid nitrogen .X-ray and histology examination were made periodically after operation to evaluate osteonecrosis and subsequent repair. Results: Total necrosis of the femoral head was confirmed by histology. Three days later after freezing ,osteocyte, chondrocyte and bone marrow were necrotic, and trabeculae kept intact.The minimum of the empty lacunae rate was 71%.The maximum of the empty lacunae rate was 93%. After three weeks, repair process began. Bone repair had two kinds of types which were intramembranous ossification and endochondral ossification. Five weeks later after freezing, new-formed bone either appeared in the intertrabecular space or covered the dead trabeculae. At 7 weeks, new-formed bone increased, in the meantimes, a part of dead trabeculae became thin, irregular or broken. The animals showed similar feature to that described in human FHN...