Cyclosporin A and osteonecrosis of the femoral head.

A vascular osteonecrosis has occurred in 5 to 40 per cent of patients who have undergone transplantation of a kidney and generally has been considered to be a complication of the use of corticosteroids. Currently cyclosporin A is in general use for its immunosuppressive property, so that a lower dose of corticosteroids is needed. We analyzed the cases of a series of our patients who underwent transplantation of a kidney in order to find out if our present regimen, using cyclosporin A, influenced the prevalence of osteonecrosis of the femoral head. Of a total of 270 patients, osteonecrosis of the femoral head developed in fifteen of 174 who received conventional immunosuppressive therapy and in only one of ninety-six who received cyclosporin A (p less than 0.05). During the first two months after transplantation, the mean dose of prednisone was approximately 2.5 milligrams per kilogram of body weight per day in the group that received conventional immunosuppressive therapy and approximately 1.1 milligrams per kilogram of body weight per day in the group that received cyclosporin A (p less than 0.001). We concluded that the pathogenesis of the osteonecrosis in patients who underwent transplantation of a kidney was probably related to the higher doses of corticosteroids that were administered.