The natural history of clinically occult avascular necrosis in systemic lupus erythematosus

Abstract

Patients with systemic lupus erythematosns (SLE) are at an increased risk of developing avascular necrosis (AVN) of bone. To study the epidemiology and natural history of these clinically occult lesions, we have prospectively evaluated 68 SLE patients. All patients had been maintained on a minimum of five rag/day of Prednisone for at least six months and none had hip symptomatology. A modified MRI of both hips was performed on each patiem. A complete MR1 evaluating class and percentage of femoral head involvement, AP and lateral pfain film xrays, bone scan and physical exam were performed for each patient with a positive MR1. Repeat MRI s were obtained at three month intervals to assess possible progression or resolution. Eleven asymptomatic hips (8%) in eight patients had MRI documented AVN. These patients were followed on a yearly basis. The percentage of femoral head involvement ranged from 1-46%. One lesion was MRI class B., the remaining lesions were class A. The radiographic stage of ten hips was stage 0, the MRI class B hip was stage 1. Risk factors for dinicany occult AVN included Afro-American origin, Raynand's phenomenon, migraine headaches, t oba c c o use a n d a m a x i m a l co r t i cos t e ro id dose of at least 30 rag/day. Examination and MRI follow-up of all patients with positive MR1 findings at 3 years continues to show no progression of AVN. Additionally, all patients have remained asymptomatic.