Silent osteonecrosis of the femoral head following high-dose corticosteroids in patients with systemic rheumatic diseases

Background: Osteonecrosis (ON) is known to be one of the most disabling complications following corticosteroid (CS) medications. However, evidence regarding risk of asymptomatic prevalence of ON among different diseases and the impact of variable steroid regimens are conflicting. We aimed to determine the prevalence of ON of femoral head in asymptomatic patients with systemic rheumatic diseases who received high-dose CS and also clarify its relationship with different dosages and regimens. Methods: In this cross-sectional study, 50 consecutive patients receiving high-dose CS for rheumatic diseases who have no pelvic pain were recruited. MRI of both hips was performed on all patients using a 1.5 Tesla to diagnose ON. Results: Of 50 subjects, 18 (36%) developed ON of the femoral head. Groups with and without ON were comparable in terms of sex, age and mean starting CS dose. There was no statistical difference in the type of CS regimen including daily dose, peak dose and cumulative dose between the two groups. However, silent ON was associated with both the cumulative CS dose and the duration of CS therapy. Conclusion: According to high prevalence of ON in our selected patients with no other identifiable risk factor for ON, monitoring of high risk patients with periodic hip MRI would help diagnose necrosis in early stage.