Risk Factors of avascular Osteonecrosis of the Femoral Head in Children at the National Reference Center for Sickle Cell Disease in Brazzaville, Congo

Introduction: The avascular osteonecrosis of the femoral head (AOFH) is a common complication of sickle cell disease (SCD). It exposes to lameness and sometimes to a very debilitating handicap. It is a source of desocialization, particularly in developing countries where prosthetic surgery remains inaccessible to the majority. This survey aimed to identify the risk of occurence AOFH.

Materials and Methods: It was a case-control study carried between october 2017 and september 2021 at the National Reference Center for SCD « Antoinette Sassou Nguesso » in Brazzaville. It concerned 31 children with clinical and radiographic signs of AOFH. Clinical (age at diagnosis of SCD, frequency of vasoocclusive crises and hospitalization for vasoocclusive crises, number of blood transfusion) as well as hematological examination (blood count in the intercritical period) and hydroxyurea treatment were compared with those of 62 children with no clinical and radiographic signs of AOFH. The chi2 statistical test and the odds ratio were used for the comparison (P ˂ 0.05).

Results: The sex ratio was 1.38 versus 0.93 (p = 0.50). The mean age of diagnostic of SCD was 3.76 ± 2.56 years versus 3.94 ± 2.01 years (p = 0.81). Logistic regression showed that SCD children with AOFH had a significantly higher rate of annual frequency of VOC (4.16 ± 1.18 vs 2.91 ± 1.68; P = 0.015), annual frequency of hospitalization for VOC (3.74±1.65 vs 1.45 ± 1.28; P = 0.000) and number of blood transfusions (3.38 ± 2.69 vs 2.42 ± 2.32; P = 0.03).

Conclusion: Emphasis should be placed on the prevention and early management of acute complications of SCD. The role of hydroxyurea should be clarified by further work.