MRI Follow-Up and Natural History of Avascular Necrosis of the Femoral Head in Kuwaiti Children With Sickle Cell Disease

PURPOSE: : To document the MRI progression and the natural history of avascular necrosis of the femoral head (AVNFH) in Arab children with sickle cell disease. PATIENTS AND METHODS: Twenty-three SS and 7 SbetaThal patients (aged 6-17 years) were screened for AVNFH between 1998 and 1999. Eight (26.7%) were identified with varying degrees of AVNFH. Seventeen of the original 30 patients have now been followed for 1 to 4 (mean 2.0 +/- 1.2) years, with repeat MRI of the hips. Spin-echo T1-and T2-weighted images and T2 fat-saturation sequences were obtained using a 1.5-Tesla GE unit with superconductors. AVNFH was graded I (mild), II (moderate), or III (severe). RESULTS: Eleven (64.7%) of the 17 patients had significant progression of their lesions; at the initial study, 9 were normal, 7 were grade I, 1 was grade II, and none was grade III. At the end of the follow-up period, two were normal, seven were grade I, one was grade II, and seven were grade III. Of the nine who were initially normal, two still had no lesions, while four were grade I and three were grade III on follow-up. Of the seven who were classified as grade I initially, four remained at grade I, one moved to grade II, and two became grade III. The one patient who was initially grade II progressed to III. CONCLUSIONS: AVNFH is a common, chronic, and unrelenting complication in children with sickle cell disease, and it is usually progressive.