Osteonecrosis in Sickle-Cell Disease

Abstract

Sickle-cell disease (SCD), an autosomal recessive disorder, is also called sickle-cell anemia (SCA) due to the hemolytic anemia characterized by abnormally shaped (sickled) red blood cells (RBCs), which are removed from the circulation and destroyed at increased rates, leading to anemia. Of greater clinical importance, the sickled RBCs cause vascular occlusion, which leads to tissue ischemia and infarction. The patients who are homozygous for the sickle-cell gene (hemoglobin SS) have a high risk of bone osteonecrosis [1–3] due to microvascular occlusion in relation to the disturbance in the erythrocyte architecture and the polymerization of hemoglobin S (in a deoxygenated state) producing cells that are crescent- or sickle-shaped with decreased deformability; the decreased deformability results in greater risk for clotting in small vessels. The incidence of osteonecrosis is also high in patients with hemoglobin SC (compound heterozygotes for Hb S- and Hb C-producing alleles: SC) and in the various types of sickle-beta-thalassemia (SThal) population. So, patients with sickle-cell disease often present with orthopedic disease manifestations requiring surgical intervention, with the most common indications being osteonecrosis and osteomyelitis. This article based on the experience of the authors treating more than 2,000 patients with SCD reviews the incidence of multifocal osteonecrosis in this disease, the distribution of the joints concerned by multifocal osteonecrosis, and the clinical consequences in the long term (average 15 years of follow-up) of multifocal osteonecrosis in these patients with sickle-cell disease and includes an approach to the medical and surgical management of patients with orthopedic complications related to sickle-cell disease.