To better simulate the inflammatory state of patients with steroid-induced osteonecrosis of the femoral head (SONFH) before disease onset, the combined modeling method using an adjuvant [lipopolysaccharide (LPS) or allogeneic serum] plus glucocorticoids has been widely recognized as the most appropriate approach for establishing SONFH models. LPS is a substance that can induce fever and microcirculatory disturbances, and in severe cases, can trigger intravascular coagulation and related symptoms. Studies have shown that using glucocorticoids alone to establish an SONFH model cannot fully recapitulate the clinical pathogenesis of SONFH. Adding an adjuvant not only shortens the modeling period and improves the success rate of model establishment, but also establishes an initial immune response prior to steroid intervention, which is more consistent with clinical reality. In fact, most clinical cases of SONFH develop in patients who receive high-dose and long-term glucocorticoid therapy for underlying hematological or immune system disorders, which eventually leads to osteonecrosis. Therefore, the combined modeling strategy of adjuvant plus glucocorticoid — in which adjuvant first induces systemic dysfunction followed by steroid administration — can more closely simulate the clinical onset and progression of SONFH, and better conform to its underlying pathogenic mechanism.

- **Animals**: Male SD rats, 6–8 weeks old
- **Model establishment**: Two days after intraperitoneal injection of LPS, methylprednisolone sodium succinate (MPS) was injected intramuscularly into the gluteus for 3 consecutive days. The steroid-induced osteonecrosis of the femoral head (SONFH) model was successfully established 6 days later.
- **Evaluation indexes**: ELISA detection, HE staining

ELISA detection

Bone tissue HE staining