60%(lot number 20040828, Jiahui, Shanghai, China).METHODS:Rabbit autologous BMSCs were isolated and cultured in vitro.At the third passage, BMSCs at 2?1010/L were combined on 3 cm?2 cm gelatin sponge.Each gelatin sponge contained 60 ?L cell suspension, placed in a cell incubator for 4 hours for further use.In each group, rabbit models of steroid-associated femoral head necrosis were established by liquid nitrogen frozen method.After natural rewarming, a hole was drilled.Rabbits in the model control group were left intact.Rabbits in the decompression group were implanted with gelatin sponge.Rabbits of the BMSC transplantation and theaflavin + BMSC transplantation groups were implanted with gelatin sponge with rabbit autologous BMSCs, and perfused with 250 mg theaflavin three time every day till death.MAIN OUTCOME MEASURES:The following parameters were measured:general conditions of animals;signal changes in the femoral head necrosis region were observed in the hip by magnetic resonance imaging scanning.Histology of femoral head samples was observed.Results of scanning electron microscope observation.RESULTS:After 8 weeks, rabbits became more active than before treatment, and walking way became normal gradually in the BMSC transplantation, theaflavin + BMSC transplantation groups.Four weeks after model induction, magnetic resonance imaging signal region of all groups had no obvious changes, but 8 weeks later, the necrosis signal region of the model control group magnified while it reduced obviously in the decompression group.Low signal region range became slightly small in the cell transplantation group.The low signal region range became significantly small in the theaflavin + BMSC transplantation group, and bone density signal was nearly normal.Compared with other three groups, positive number of empty lacunae significantly reduced in the theaflavin + BMSC transplantation group at 4 and 8 weeks following model induction(P