Extract
This issue contains two articles on osteonecrosis of the femoral head in
patients with sickle cell disease: "The Natural History of Asymptomatic
Osteonecrosis of the Femoral Head in Adults with Sickle Cell Disease,"
by Hernigou et al., and "Physical Therapy Alone Compared with Core
Decompression and Physical Therapy for Femoral Head Osteonecrosis in Sickle
Cell Disease: Results of a Multicenter Study at a Mean of Three Years After
Treatment," by Neumayr et al. Both are meaningful studies that add to
our body of knowledge in the orthopaedic management of patients with sickle
cell disease but appear to report strikingly different outcomes in similar
patient populations. In the report by Hernigou et al., ninety-one (75%) of 121
patients required reconstructive surgery during the term of the study, with
total hip replacement being performed in forty-two patients, valgus femoral
osteotomy in twenty-three, and injection of cement into the femoral head in
twenty-six. In comparison, in the study by Neumayr et al., only three (7.9%)
of thirty-eight patients required reconstructive surgery in the form of total
hip replacement. There are some similarities between the two studies, but
several important differences may account for some of the variance in outcome.
The two studies are compared in Table
I. The average age (twenty-six years) was the same in both
studies. However, the patients in the study by Neumayr et al. were as young as
ten years old, whereas the youngest patient in the study by Hernigou et al.
was eighteen years old. The prevalence of hemoglobin SS was 76% in the study
by Neumayr et al., compared with 40% in the study by Hernigou et al. In the
latter study, 48% of the patients had hemoglobin SC disease. Seventeen (45%)
of the thirty-eight patients in the study by Neumayr et al. had Steinberg
stage-III involvement at the beginning of the study, whereas none of the
patients in the study by Hernigou et al. had more than stage-II involvement.
Each of these factors might be expected to result in a worse outcome for the
group in the study by Neumayr et al.