Spontaneous repair of asymptomatic osteonecrosis associated with corticosteroid therapy in systemic lupus erythematosus: 10-year minimum follow-up with MRI.

Systemic lupus erythematosus (SLE) patients are at high risk of developing osteonecrosis. This study utilized MRI to document the long-term natural history of asymptomatic osteonecrosis associated with corticosteroid therapy in SLE patients. Two hundred and one SLE patients treated with high-dose corticosteroids were prospectively observed from 1986 to 1997. The inclusion criterion was that patients had received periodic MRI examinations of all their hip and knee joints for ≥10 years. Joints that were already collapsed and symptomatic at the first examination were excluded. Five hundred and thirty-seven joints (251 hips and 286 knees) were identified in 144 patients, with a mean follow-up period of 13.6 years (range, 10-20 years) and a follow-up rate of 73%. Mean age of SLE onset was 26 years, and the mean highest oral corticosteroid dosage was 57 mg/day. Osteonecrosis developed in 238 (44%) of 537 joints. At final follow-up, 117 (49%) of these 238 joints demonstrated spontaneous repair in the necrotic area. Osteonecrosis completely disappeared in 21 joints. Enlargement of osteonecrosis was noted in 35 joints (15%) following increased steroid dosage because of SLE recurrence. Finally, 52 joints (22%) were collapsed. Spontaneous repair of asymptomatic osteonecrosis was observed, whereas enlargement occurred only after corticosteroid dosage increases.