Clinical characteristics of multifocal osteonecrosis in Korean patients with rheumatic disease

Aim: Osteonecrosis (ON), also known as avascular necrosis, is an important cause of physical disability in rheumatic disease. When this condition affects multiple structures, disability is increased. The purpose of this study was to describe the clinical characteristics of Korean patients with multifocal ON associated with rheumatic disease and to compare them with those of previously reported cases.Methods: We reviewed the clinical characteristics of eight Korean patients with multifocal ON, defined by the involvement of three or more anatomic sites, associated with rheumatic disease in a single referral academic hospital, and compared them with those of 19 similar cases previously reported in the literature.Results: All eight patients were female, with median age of 26 years. All had underlying systemic lupus erythematosus (SLE) and had been using corticosteroids. The most common site affected by ON was the knee joint. However, in contrast to our patients, the previous reported cases had other rheumatic diseases such as myositis, scleroderma and antiphospholipid syndrome. In comparison between Korean multifocal ON patients with SLE and those of previous reports, shoulder joint involvement was higher in previous reports. Common features in patients from both groups were knee joint involvement and prevalent use of corticosteroids.Conclusion: Our findings indicate that multifocal ON is common in young SLE patients who have been using corticosteroids and the most commonly involved site is the knee