[Cortisone-induced osteonecrosis: knowledge acquired from observations in man and comparison with the results of animal experimentation].

Aseptic osteonecrosis is observed in 25% of cases after renal transplantation. This etiological variety of osteonecrosis is unusual in that it is frequently bilateral and has multiple localisations. Apart from the classical radiological signs, attention in attracted by isolated images of osteocondensation in the metaphyses and/or the diaphyses suggesting massive bony infarction and the appearances of fatigue fractures observed frequently (14%). In 43% of cases, the obvious necrosis was proceeded by early bone pain, around the 7 th day, during massive administration of corticosteroids in the prevention or cure of graft resection. This finding suggested to us that the best time to observe ischemia of the bone or marrow is very early and led us to undertake an experimental study in the rabbit. Two series of New Zealand White rabbits were treated with massive doses of corticosteroid and sacrificed between the 3rd and the 21st day. The treated animals presented an early peak of hyperlipemia from the 7th day onwards, and diffuse lesions of hepatic and renal steatosis. Fat emboli associated with appearances of parietal thrombosis were observed in most cases. In the same animals, there were also appearances of stage I or stage II necrosis. Referring to the description of bone marrow necrosis in stages by Arlet and Ficat, there was observed in all the series, a frequency of marrow lesions of all stages much higher in treated animals (16 out of 20) than in controls. Only one lesion of stage I was observed in controls; the difference was highly significant. (0,000001 < p < 0,00001). If one only considers necroses of stage II and III (10/20 in the treated group nil in controls) the frequency was still significant p < 0.001. The preliminary results of the fixation of tetracycline are reported.