RESUMEN
Avascular necrosis of the femoral head [ANFH] in Saudi patients with homozygous sickle cell [SS] disease attending King Faisal Specialist Hospital and Research Centre [KFSH and RC] occurred in 29/118 [24.6%] patients or 32% of patients aged 10 years and above. This high prevalence was heavily influenced by symptomatic selection. Contrary to observations in patients of African origin, ANFH in Saudi subjects was not associated with high hemoglobin, low fetal hemoglobin levels or with alpha thalassemia. Bone densitometry failed to detect differences in bone mineral density or content between patients with and without ANFH. Levels of 25-OH vitamin D did not differ between patients with and without ANFH. Several patients showed very rapid and complete destruction of the femoral head suggestive of osteomyelitis of the femoral head or a pyogenic arthritis. ANFH appears common in Saudi patients with SS disease although an accurate prevalence is unknown. The lack of relationship with risk factors for ANFH identified in African SS disease highlights the need for further study in the Saudi SS population