The purpose of this diagnostic study was to quantify the effect of high-dose corticosteroid treatment on hip joint cartilage degeneration in patients with systemic lupus erythematosus (SLE), with and without osteonecrosis, using magnetic resonance imaging (MRI).
T2 mapping, with a 3.0 Tesla Discovery MR750 (GE Healthcare) MRI scanner, was performed in 12 volunteers without hip pathology (control group, 12 hips), in 11 patients with SLE without osteonecrosis, who were receiving corticosteroid therapy (corticosteroid-ON group, 17 hips), and in 15 patients with SLE receiving corticosteroids, who had noncollapsed and asymptomatic osteonecrosis (corticosteroid+ON group, 26 hips). The distribution of T2 values in the femoral head and acetabular cartilage were compared among the three groups. Step-wise multiple regression analysis was performed to determine the prognostic factors for T2 values indicative of femoral head cartilage degeneration.
Mean T2 values of femoral head cartilage were significantly higher in the corticosteroid-ON (40.3 ms) and corticosteroid+ON (35.2 ms) groups than in the control group (30.1 ms, P = 0.001). T2 values of acetabular cartilage were significantly higher in the corticosteroid-ON group (41.8 ms) versus the control (33.4 ms) and the corticosteroid+ON groups (37.0 ms; P = 0.001). Low bone mineral density was a significant prognostic factor for high T2 values of cartilage at the femoral head in patients treated with corticosteroids, regardless of whether they had osteonecrosis.
T2 mapping suggests that corticosteroid therapy and osteoporosis are independent risk factors for cartilage degeneration at the femoral head in patients with SLE.