Avascular necrosis of bone following renal transplantation.

Assessment of 78 successful renal transplants carried out in Newcastle upon Tyne between October 1967 and March 1973, revealed avascular necrosis of bone (A.N.) in 11 patients (14 percent). Pain and restriction of movement were the cardinal symptoms, while the onset was from five to 35 months after transplantation. In some patients one joint only was affected but in seven patients (64 per cent) A.N. developed in other joints too in an additive and progressive fashion. A time lag was usually noted between the onset of symptoms and radiological proof. These 11 patients with A.N. were compared with two control groups of unaffected renal transplant patients. Taking into account the patients' body weight, the cumulative dose of prednisone received by affected patients during the first three post-transplant months was found to be significantly higher than that for both control groups (P less than 0.05). Patients with A.N. were found to have had an unusually high incidence of early post-transplant surgical complications and the length of their initial stay in hospital was significantly prolonged (P less than 0.02) when compared to both control groups. It is possible that excessive corticosteroid therapy is more deleterious in transplant patients weakened by peri-renal haematomas, urinary extravasations and stormy prolonged post-operative periods. Having emphasized the detrimental effects of excessive anti-rejection corticosteroid therapy it must be mentioned that occasionally patients develop avascular necrosis even after low doses of steroid therapy, while others, receiving high doses of steroid therapy and undergoing a stormy post-operative course, do not develop this complaint. It is suggested that although excessive steroid therapy is positively harmful, avascular necrosis is not an invariable complication and that ofther factors including possibly a genetic predisposition operate to produce avascular necrosis of bone in renal transplant patients.