Steroid-associated hip joint collapse in bipedal emus.

Area of Science:

• Orthopedics
• Preclinical Research
• Animal Models

Background:

• Steroid-associated osteonecrosis (SAON) is a debilitating condition.
• Current preclinical models for SAON have limitations.
• Effective models are needed for developing preventative treatments.

Purpose of the Study:

• To establish a bipedal emu model for SAON.
• To evaluate the efficacy of a combined pulsed lipopolysaccharide (LPS) and methylprednisolone (MPS) protocol for SAON induction.
• To assess the model's suitability for testing therapeutic interventions.

Main Methods:

• Five adult male emus received pulsed LPS and MPS; three served as controls.
• Gait analysis, MRI, and blood tests were performed post-induction.
• Micro-CT, histomorphometry, and SEM were used for bone and tissue analysis.

Main Results:

• Steroid-treated emus exhibited limping gait and abnormal MRI signals.
• SAON developed in all treated emus, with a 70% incidence of joint collapse.
• Significant changes in neutrophil percentage, lipid metabolism, subchondral bone structure, and cartilage were observed.

Conclusions:

• The pulsed LPS and MPS protocol effectively induces SAON and hip joint collapse in emus.
• Bipedal emus serve as a viable preclinical model for SAON research.
• This model can be used to evaluate potential treatments for preventing steroid-induced hip joint collapse.