The natural progression of symptomatic humeral head osteonecrosis in adults with sickle cell disease.

BACKGROUND Osteonecrosis of the humeral head is a frequent complication in adults with sickle cell disease. However, little is known about the rate of, and the factors influencing, progression of symptomatic shoulder osteonecrosis in patients with this disease. METHODS Eighty-two adult patients with sickle cell disease and symptomatic osteonecrosis of the humeral head (104 shoulders) were identified with magnetic resonance imaging (MRI) between 1985 and 1993. Nineteen of the eighty-two patients were homozygous for hemoglobin S (S/S genotype), thirty-seven had hemoglobin S/hemoglobin C (S/C), and twenty-six had hemoglobin S/beta-thalassemia (S/T). Shoulder osteonecrosis was graded with the method of Cruess with an adaptation for MRI as proposed by Steinberg et al. for hip osteonecrosis. Annual radiographs were obtained. At the initial evaluation, thirty-eight symptomatic shoulders were designated as stage I (with osteonecrosis seen only on MRI), forty-two symptomatic shoulders were designated as stage II (radiographic evidence without collapse), and twenty-four symptomatic shoulders were designated as stage III or IV (a crescent line or collapse). RESULTS Partial or total repair with a decrease in the size of the osteonecrotic lesion or in the stage was never observed on MRI. At the time of the most recent follow-up (average, twenty years; range, fifteen to twenty-four years), collapse had occurred in eighty-nine shoulders (86%). The mean interval between the onset of pain and collapse was six years (range, six months to seventeen years; median, eight years). Of the 104 symptomatic shoulders, sixty-three (61%) with collapse worsened clinically until surgical treatment was needed. The principal risk factors for development of shoulder osteonecrosis in adults with sickle cell disease were the presence of hip osteonecrosis and the S/T or S/C genotype. The rate and risk of progression of the lesion until collapse occurred were significantly related to the S/S genotype, to a stage of II, to a large size of the osteonecrotic lesion, and to a medial or posterior location of the lesion. CONCLUSION Untreated symptomatic shoulder osteonecrosis related to sickle cell disease has a high likelihood of progressing to humeral head collapse, and the natural evolution in the long term requires surgical treatment for many of these patients.