Talar Osteonecrosis Related to Adult Sickle Cell Disease: Natural Evolution from Early to Late Stages.

BACKGROUND

Little is known about the rate of, and factors affecting, progression of talar osteonecrosis related to sickle cell disease. Adult patients with sickle cell disease who presented with hip osteonecrosis were evaluated for talar osteonecrosis with radiographs and magnetic resonance imaging (MRI). Forty-five of them (75 tali) were diagnosed with talar osteonecrosis, and this group was evaluated for factors influencing the progression of the disease.

METHODS

Forty-five patients with sickle cell disease and osteonecrosis of the talus were identified with radiographs and MRI between 1985 and 1995. Seven of these patients were homozygous for hemoglobin S (S/S genotype), 26 had hemoglobin S/hemoglobin C, and 12 had hemoglobin S/beta-thalassemia. The talar osteonecrosis was graded with radiographs and MRI. The patients were followed with clinical examination and radiographs every 6 months until talar collapse and every year after the collapse.

RESULTS

The osteonecrosis was unilateral in 15 patients and bilateral in 30 at the time of the initial examination. Forty-five ankles were asymptomatic and 30 were symptomatic at the initial evaluation. MRI performed at the time of the most recent follow-up, and compared with MRI performed at diagnosis, did not show partial or total regression of the osteonecrosis in any of the patients, even those with asymptomatic stage-I osteonecrosis. At the time of the most recent follow-up (mean, 20 years; range, 15 to 25 years), pain and collapse had developed in all except 12 ankles. The stage of the osteonecrosis at the initial visit, pain, the genotype of the sickle cell disease, and the extent and location of the lesion in the talus were risk factors for progression of the disease.

CONCLUSIONS

In the majority of the patients with sickle cell disease, osteonecrosis of the talus should be expected to show relevant clinical and radiographic evidence of progression over a long period.

LEVEL OF EVIDENCE: Prospective Level II. See Instructions for Authors for a complete description of levels of evidence.