Subchondral trabecular compression of the femoral head in the etiology of aseptic necrosis. Experimental study in rabbits

Subchondral trabecular compression of the femoral heads of rabbits was produced to test the hypothesis that trauma to the subchondral trabecular structure plays a role in the etiopathology of aseptic necrosis. Compression led to bone necrosis in the area of trauma, and acellular fragments were still observed after six months. The repair response was vigorous and led to an increase of bone mass in relation to marrow vascular space. It is suggested that the new bone formation in the area of trauma, as well as in the surrounding areas, prevented collapse of the femoral head. Use of local or systemic methods to suppress the repair response was not investigated in this study. It is possible that inhibition of the repair process in a localized area of bone destruction might cause greater stress to be placed on the surrounding trabeculae, perhaps leading to bone death by excessive loading and stress fractures.