Steroid-induced osteonecrosis of the patella.

Two cases of previously unreported steroid-induced osteonecrosis of the patella were investigated. The first case was a 46-year-old man who had been receiving steroid therapy for three years for treatment of bronchial asthma. The second was a 32-year-old woman who had been receiving steroid therapy for nine years as treatment of systemic lupus erythematosus. Both reported slight knee pain. The roentgenographic findings revealed increased radiodensity with radiolucency of the upper one-half of the patella. A trephine biopsy revealed focal areas of dead trabecular bone.