Inducing an animal model of avascular necrosis of the femoral head through exercise

Abstract

Objective To establish an immature rabbit model of avascular necrosis of the femoral head in-duced by exercise. Methods Ten male, immature New Zealand white rabbits were subjected to large range, in- tense passive movement and concentric impingement on their right hips for 4 weeks. The left hips were used as self-controls. Then X-ray and magnetic resonance imaging, gross anatomical observation and histological examination were used to evaluate avascular necrosis of the femoral head. Result After 4 weeks, avascular necrosis of the femoral head was successfully replicated. Increased bone density, decreased osteoepiphysis height and indistinct bone trabec-ula were found in X-rays of the right hips. In MRI images obvious joint hydrops could be detected in all right hips, and schistic low signal areas in the femoral head could be seen in TIWI and T2WI images. Thin bone trabeculae of low density, with irregular and broken structures, were also found in H-E sections. Conclusion An immature rab-bit model of avascular necrosis of femoral head can be successfully induced through large range, intense, passive movement and concentric impingement. Key words: Avascular necrosis of the femoral head; Immature rabbits; Exercise