Osteonecrosis is related to the use of steroids in patients with systemic lupus erythematosus (SLE); its association with the use of 'pulses' of methylprednisolone (PMP) is not clear at present. In a retrospective analysis of 190 patients with SLE we found that 19% of 36 patients treated with PMP had osteonecrosis compared with 6% of 154 patients without that treatment (P < 0.04). Risk factors associated with osteonecrosis were PMP treatment, cushingoid appearance, steroid doses > or = 40 mg/day during the first month of treatment, a ratio of steroid dose in grams/year > or = 12, hematuria and proteinuria. In a stepwise regression model, when cushingoid appearance was excluded, PMP became the only significant factor (P = 0.045). We conclude that osteonecrosis can be considered a long-term complication of PMP treatment in SLE patients.