Structural examination of experimental femoral head avascular necrosis

Abstract

Aim. To conduct histological analysis of femoral head avascular necrosis in Wistar rats.Materials and Methods. Femoral head avascular necrosis was artificially induced in 12 Wistar rats which have been euthanised at 2, 4, 6, and 8 weeks postoperation (n = 3 per time point). Affected and intact femoral heads were examined by X-ray examination, haematoxylin and eosin staining, and scanning electron microscopy.Results. X-ray examination and haematoxylin and eosin staining showed the progressive development of osteonecrosis from 2 to 6 weeks and initiation of bone repair at 8 weeks postoperation. X-ray examination had less informative value as compared to routine histological examination. Progressive loss of bone volume was accompanied by osteolysis, resorption of hyaline cartilage, and replacement of bone and cartilage tissues with collagen fibers. Scanning electron microscopy provided an opportunity to assess cellular composition and showed that the maximum activity of osteoclasts and osteoblasts occurs at 6 and 8 weeks postoperation, respectively.Conclusion. X-ray examination was dispensable when investigating features of femoral head avascular necrosis. Histological examination using haematoxylin and eosin staining permitted detection of bone resorption, while scanning electron microscopy contributed to high-resolution visualisation of the bone cellular composition.