Background: Osteonecrosis of the femoral head is a frequent
complication in adult patients with sickle cell disease. However, little is
known about the natural history of asymptomatic lesions.
Methods: One hundred and twenty-one patients (121 hips) with sickle
cell disease and asymptomatic osteonecrosis of the femoral head that was
contralateral to a hip with symptomatic osteonecrosis were identified with
magnetic resonance imaging between 1985 and 1995. The lesions were graded with
use of the Steinberg classification system. The patients were followed with
annual plain radiographs. The mean duration of follow-up was fourteen
Results: At the time of the initial evaluation, fifty-six hips were
classified as Steinberg stage 0, forty-two hips were classified as Steinberg
stage I, and twenty-three hips were classified as Steinberg stage II. At the
time of the most recent follow-up, pain had developed in 110 previously
asymptomatic hips (91%) and collapse had occurred in ninety-three hips (77%).
Symptoms always preceded collapse. Of the fifty-six hips that were classified
as Steinberg stage 0 at the time of the initial evaluation, forty-seven (84%)
had symptomatic osteonecrosis and thirty-four (61%) had collapse at the time
of the most recent follow-up. Of the forty-two asymptomatic stage-I hips,
forty (95%) became symptomatic within three years and thirty-six (86%) had
collapse of the femoral head. Of the twenty-three asymptomatic stage-II hips,
all became symptomatic within two years and all collapsed; the mean interval
between the onset of pain and collapse was eleven months. At the time of the
final follow-up, ninety-one hips (75%) had intractable pain and required
Conclusions: Untreated asymptomatic osteonecrosis of the femoral
head in patients with sickle cell disease has a high likelihood of progression
to pain and collapse. Because of the high prevalence of complications after
total hip arthroplasty in patients with this disease, consideration should be
given to early surgical intervention with other procedures in an attempt to
retard progression of the disease.
Level of Evidence: Prognostic Level II. See Instructions
to Authors for a complete description of levels of evidence.