Histological observation of subchondral bone following collapse of osteonecrosis of the femoral head

Objective To observe the histological changes of subchondral bone following collapse of osteonecrosis of the femoral head and to explore the relationship between the morphological changes of the subchondral bone and the difficulty in bone grafting healing.Methods Twenty-five specimens of femoral head were collected from patients who underwent total hip replacement due to alcoholic osteonecrosis of the femoral head.Pathological sections from different parts of the femoral head including normal,junctional and necrotic area were obtained and stained with hematoxylin and eosin (HE) method.The cartilage and subchondral bone from different parts were observed histologically.Results Seventeen of all specimens showed that integrity of the subchondral bone was severely damaged at junctional area with subchondral bone being separated from the calcified cartilage in the rest.Twenty-two of all specimens had fracture of subchondral bone which was separated from calcified cartilage in the necrotic area.Conclusion Fracture through the whole subchondral bone to the calcified cartilage with seperation of subchondral bone from calcified cartilage in necrotic area may be responsible for difficulty in bonegraft healing. Key words: Osteonecrosis of the femoral head;  Collapse;  Histology;  Subchondral bone