Avascular necrosis of the femoral head in sickle cell disease in Nigeria: a retrospective study.

BACKGROUND: Avascular necrosis (AVN) especially of the femoral head, has long been recognised as a manifestation of sickle cell disease (SCD). Despite this knowledge the actual prevalence of this complication among sickle cell patients in Nigeria is not known.
OBJECTIVE: To determine the prevalence and patterns of presentation of avascular necrosis of the femoral head in sickle cell disease. PATIENTS AND METHODS: A retrospective study carried out at the Orthopaedic and Haematology clinics of Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Nigeria. Four hundred and sixteen patients with sickle cell disease seen over a 15-year period.
RESULTS: Of the 416 patients with sickle cell disease 340 (81.7%) had haemoglobin SS genotype while 76(18.3%) had SC genotype. Sixty-six (15.9%) patients 35 males (53%) and 31 females (47%) had clinical and radiologic features of avascular necrosis (AVN) of the femoral head. Fifty-three of them (80.3%) had Hb SS while 13 had Hb SC. The peak age incidence in both Hb SS and Hb SC was 21-30 years. Forty patients (60.6%) presented with stage IV disease (Ficat and Arlet Staging) while 21.2% had stage III and 18.2% had stage II. No patient was diagnosed in stage 1 or 0.
CONCLUSION: The prevalence of AVN of femoral head in Hb SC and HbSS is similar i.e. the difference is not statistically significant (P=0.48). Most of our patients present late with advanced diseases. Considering the paucity of facilities available for total hip replacement in Nigeria and the young age group affected we recommend regular screening of patients with sickle cell disorder for AVN and regular community educational programmes for early diagnosis.