[Epidemiology of the severe hip disorders in children in Benin: prospective study of 180 cases over a 7 year period].

Purpose Of The Study: In Benin, the etiological diagnosis of serious hip disorders is often difficult and satisfactory epidemiological data are lacking. The purpose of this study was to establish the relative frequencies of pathological conditions leading to serious hip disorders in Benin.

Material And Methods: We report 180 cases of severe hip disorders in 170 children hospitalized over a 7-year period from January 1, 1992 through December 31, 1998. The prospective study was based on clinical and conventional radiological findings, laboratory results and clinical course.

Results: The annual frequency of new cases was: septic arthritis of the hip 18.8 (73.3%), legg-Calvé-Perthus disease 2.9 cases (11%), aseptic osteoarthritis of the femoral head 2.3 cases (8.9%), superior femoral epiphysiolysis 0.9 cases (3.3%), coxalgia 0.9 cases (3.3%), accounting for 25.7 new cases of serious hip disorders per year.

Discussion: Sickle-cell disease or trait (SS or SC hemoglobin) was the cause of aseptic osteonecrosis of the femoral head in 83% of the cases. For the other serious hip disorders, 30% were observed in sickle-cell trait patients and only 2.7% in patients with sickle-cell disease (SS or SC). These rates are similar to those in the general Benin population.

Conclusion: These data offer a better perception of the causes of serious hip disorders observed in children in Benin. Further studies are needed to obtain precise data by nosological entity. Legg-Calvé-Perthes disease, unknown in Benin up to 1992, now is the second leading cause of severe hip disorders and their sequelae.