Avascular necrosis (AN) of bone is a complication of systemic lupus erythematosus (SLE). In the present paper we describe two patients with SLE who presented an AN of femoral condyles 18 months and 2 years respectively after the diagnosis of the disease. In the second case, together with the destructive change of the symptomatic knee, X-ray films showed an initial involvement, still asymptomatic, of the contralateral knee
