A cross sectional study was performed to try to identify various demographic and radiologic risk factors for disease progression in 50 patients (79 hips) with corticosteroid associated osteonecrosis of the femoral head who had a core decompression. Thirty-one of the hips were in 18 patients who had systemic lupus erythematosus and were compared with the remaining group of 48 hips in 32 patients who were taking corticosteroids for other reasons. All patients in the study had been taking greater than 30 mg of prednisone for at least 2 weeks at least 6 months before the onset of osteonecrosis. Patients underwent a core decompression and were then observed for an average of 12 years (range, 4-18 years). Overall, 42 of the 79 hips (53%) had satisfactory outcomes. Of the 31 hips in patients with systemic lupus erythematosus, 21 (68%) were converted to a total hip replacement. In the patients without systemic lupus erythematosus taking corticosteroids, 16 of 48 hips (33%) progressed to arthroplasty. A subset of 25 hips from each group (systemic lupus erythematosus and without systemic lupus erythematosus) were matched for age, gender, prednisone dose, Ficat and Arlet Stage, and length of followup. The matched group without systemic lupus erythematosus had 44% survival (11 of 25 hips), which was not statistically different when compared with the 36% survival (9 of 25 hips) found in the systemic lupus erythematosus group. The major risk factors for disease progression were late stage of disease (Stage III) at presentation and radiographic extent of the lesion (>200 degrees), regardless of diagnosis. None of the factors that have been found to be associated with osteonecrosis in patients with systemic lupus erythematosus could be associated with disease progression. Because cause seems to be less significant than the onset and extent of the disease, the clinician should make the diagnosis of osteonecrosis as promptly as possible so that treatment can be started at the earliest possible time, when it will be most efficacious.