Evaluation of the Functions and Radiographic Severity of Osteonecrosis of the Head of Femur in South-west Nigeria

Background: Osteonecrosis of the femoral head is likely to be a complex of diseases rather than a single entity. In sub-Saharan Africa, epidemiological studies on the subject are uncommon. Objectives: To determine hip function, radiographic severity and other characteristics of patients with osteonecrosis of the femoral head (ONFH) at presentation in a sub-Saharan Africa population Methods: A combined prospective clinical survey and retrospective chart review of patients was done. Results: Fifty hips in 44 patients were studied (29 retrospectively and 15 prospectively). The prevalence of ONFH was 1.6%. The mean age was 24.8±13.2 years. The lesion was unilateral in 86.4% and bilateral in 13.6% of the hips. Sickle Cell Disease (SCD) occurred in 43.2%, sickle cell trait in 13.6%, and 20.5% of cases were idiopathic. Overall, 12% of affected hips were presented early, and all the hips were painful at presentation. Of the 18 hips studied prospectively, 72.2% had necrosis >30% and >30% subchondral collapse in 61.1%. The mean combined necrotic angle was moderate size, 197o±29.7o and 177.2o±69.4o for the right and left hips, respectively (p = 0.8). The mean WOMAC scores were 37.2 ±17.4 for function, 10.2±4.3 for pain and 4.2±2.7 for stiffness. Conclusion: Patients with osteonecrosis of the femoral head tended to be young adults and those with SCD. The majority present with large-sized osteonecrosis and subchondral collapse but moderate hip pain and stiffness.